triconex fta-mux cards - hptb/32/tr-ai-01

www.elconhis.com

Technical Data

Model Number

32 ChannelHart ®

Multiplexer

MUX

2700

FAULT HART TX

PWRON

Field DCS CabinetMarshalling Cabinet

RS-485 toRS-232 converter

AMS Workstation

I/O Card Racks

Elcon HIS Panel

Legend:Color • = 4-20 mA SignalColor • = HART Signal

Field Mounted HARTTransmitters & Valves

HART Interface Solutions

HPTB/32/TR-AI-01

The HPTB/32/TR-AI-01is designed for easy 2700 multiplexer integration with Tricon 9 3700A system. With the 2700 Mux integrated into the board and plug-n-play option for the DCS equipment, this provides a very clean access to the HART signals, while reducing the need for marshalling cabinets and reducing equipment that require extra cabinet space. The HART termination board provides a robust solution for on-line HART communications, interfaces up to 32 fi eld located HART devices, and it allows the user to replace the standard DCS fi eld termination panels.

• Triconex 3700A replacement FTA

• Plug n play wiring capabilities

• 2-, 3-wire or self powered transmitters

• Short circuit protected

Connections Wiring Options Field side Fixed screw terminalsControl side 56-pin ELCO style connectorRS-485 Removable screw terminalsPower Removable screw terminals

Electrical Mounting 20 – 30 VDCPower consumption 0.7 WPower fuse 315mA, 5x20mmDC isolation of HART 30 VDC

Mechanical Mounting T type (EN 50022, DIN462777-3) or G type (EN 50035, DIN462777-1) DIN railSignal Channels Up to 32 unbalanced signal loopsCommunication port RS-485, differential pair plus GNDCommunication speed 9600 or 19200 baudMax. Conductor diameter 16 AWG (2.5mm2)Weight 18 oz. (510 g)Dimensions 10.1” x 4.9” x 3.1” (L x W x H) w/o mux (256mm x 125mm x 79mm) 10.1” x 4.9” x 8.2” (L x W x H) with mux (256mm x 125mm x 208mm)

Environmental Operating Temperature Range 0ºC to 55ºC (32ºF to 131ºF)Relative Humidity 5 to 90% non-condensing

Triconex I/O Interface 3700A

Installation Instruction Product installation manual www.elconhis.com/customized-triconex.html

www.elconhis.com

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DOC. 129-0153A P/N 907916

Product Installation Manual For

HPTB/32/TR-AI-01

PRODUCT INSTALLATION MANUAL DOC. 129-0153A PAGE 2 OF 20

MODEL LISTING Model Part Number Channels / Function

HPTB/32/TR-AI-01 907912 32-AI

To avoid damage, failure, or improper operation, read this manual carefully before installing and operating the equipment

Disclaimer

While the HART Interface Solution (HIS) Replacement Panels from Pepperl+Fuchs, Inc. (“HIS Replacement Panels”) are designed to extract the digital HART data from standard 4-20mA loops, the HIS Replacement Panels may not provide all of the features, or duplicate all the functions, of the panels they replaced, and Pepperl+Fuchs, Inc. makes no warranty or representation (and specifically disclaims any express or implied warranty or representation) that such HIS Replacement Panels are identical to, or will provide all of the same features or duplicate all of the same functions of, the panels they replace. The terms, conditions and limitations of any product warranties covering HIS Replacement Panels may be obtained from Pepperl+Fuchs, Inc.

The information set forth in this Manual is designed to assist the Purchaser in the installation, operation and maintenance of an HIS Replacement Panel. Such information should not be construed as a warranty or representation, express or implied, regarding the HIS Replacement Panel or its use in, or suitability for, a particular application, any such warranties or representations being specifically disclaimed. The terms, conditions and limitations of any product warranties covering HIS Replacement Panels may be obtained from Pepperl+Fuchs, Inc. Pepperl+Fuchs, Inc. reserves the right to modify or improve the designs, specifications, features and/or functions of HIS Replacement Panels at any time without notice.

Copyright and Trademark Information

This manual is copyright of Pepperl+Fuchs with all rights reserved. This manual may not be copied, in whole or in part, without the written consent of Pepperl+Fuchs. Pepperl+Fuchs reserves the right to make changes to this manual without notice.

Asset Management Solutions (AMS) is a registered trademark of Emerson Process Management. HART is a registered trademark of the HART Communication Foundation. Windows is a trademark of Microsoft Corporation. All other marks are property of their respective owners.


Table of Contents

1. GENERAL INFORMATION.......................................................................................................................................4 1.1. INTRODUCTION ........................................................................................................................................................4

1.1.1. System Overview..........................................................................................................................................4 1.1.2. HART Overview............................................................................................................................................4 1.1.3. Asset Management Solutions (AMS) Software Overview ............................................................................4

1.2. TECHNICAL SPECIFICATIONS ....................................................................................................................................5 1.2.1. MUX 2700 Specifications .............................................................................................................................5 1.2.2. HPTB Termination Board Specifications ......................................................................................................5 1.2.3. RS-485 Line Specifications ..........................................................................................................................6

1.3. QUALITY ASSURANCE ..............................................................................................................................................6 1.4. CERTIFICATIONS AND COMPLIANCE ..........................................................................................................................6

2. INSTALLATION ........................................................................................................................................................7 2.1. STORAGE................................................................................................................................................................7 2.2. UNPACKING AND INSPECTION ...................................................................................................................................7 2.3. ENVIRONMENTAL CONDITIONS..................................................................................................................................7 2.4. INTRINSIC SAFETY ...................................................................................................................................................8 2.5. MOUNTING ..............................................................................................................................................................8 2.6. CABLES...................................................................................................................................................................8 2.7. WIRING ...................................................................................................................................................................9

2.7.1. Power..........................................................................................................................................................10 2.7.2. Grounding...................................................................................................................................................10 2.7.3. RS-485........................................................................................................................................................11 2.7.4. Field Connections.......................................................................................................................................12 2.7.5. Control Connections ...................................................................................................................................15 2.7.6. HART Communicator .................................................................................................................................15

3. OPERATION ...........................................................................................................................................................15 3.1. INITIAL SETUP........................................................................................................................................................15

3.1.1. 2700 Settings..............................................................................................................................................15 3.1.2. MUX Addressing.........................................................................................................................................16 3.1.3. Baud Rate...................................................................................................................................................16 3.1.4. RS-232/RS-485 Converter .........................................................................................................................16

3.2. START-UP SEQUENCE............................................................................................................................................16 3.3. CONFIGURATION....................................................................................................................................................16 3.4. MUX INDICATORS .................................................................................................................................................16 3.5. MODES OF OPERATION ..........................................................................................................................................17 3.6. SYSTEM OPERATION..............................................................................................................................................17

4. TROUBLESHOOTING ............................................................................................................................................18 4.1. GENERAL ..............................................................................................................................................................18 4.2. MUX 2700 ...........................................................................................................................................................18

5. MAINTENANCE ......................................................................................................................................................19 6. GLOSSARY.............................................................................................................................................................19 7. CONTACT INFORMATION.....................................................................................................................................20


1. GENERAL INFORMATION 1.1. INTRODUCTION This manual provides guidance for the installation, operation, and maintenance of your P+F Multiplexer 2700 and termination board. The solution herein is specifically designed for easy Multiplexer integration with the Triconex TRICON system. Below is a list of termination boards and the Triconex I/O modules with which they were designed to interface.

HPTB/32/TR-AI-01 3700/A

The P+F Multiplexer 2700 will be referred to in this manual as the MUX 2700. All further general references to the listed termination boards will be simply HPTB. When referring to the combination of a MUX 2700 and an HPTB, they will be called the HART Interface Solution, or simply HIS. 1.1.1. SYSTEM OVERVIEW

Your HART Interface Solution interfaces up to 32 field located HART devices. The MUX 2700 is a HART signal multiplexer unit which allows access to HART communications on existing 4-20mA wiring. It acts as a gateway device routing communications between the maintenance workstation PC and the HART devices. The MUX 2700 uses Manchester encoding of the HART protocol for the RS-485 link to the maintenance workstation PC. To link to each of the HART devices the MUX 2700 communicates using Bell 202 Frequency Shift Keying (FSK). It interrogates each HART device, retrieves device information, and stores it in an internal database. This information is available to the maintenance workstation software. In this way, the MUX 2700 gives the user access to each HART device as if connected directly at the device itself. A maintenance workstation PC can use this information for configuration, maintenance, calibration, diagnostics, and data access.

The termination board design allows the DCS and field device wiring to be brought together with the MUX to complete the system. Various HPTB board designs allow interface with different I/O cards and may include configurable options including fused / filtered signal lines, loop or device powered instrument lines and 4-20mA or 1-5 VDC signals. HART Interface Solutions are supplied by P+F in several models in order to allow simple and reliable connection between SMART devices and various DCS systems. 1.1.2. HART OVERVIEW

HART is an acronym for "Highway Addressable Remote Transducer". The HART protocol makes use of the Bell 202 FSK standard to superimpose digital signals at a low level on top of the 4-20mA signal. This enables two-way communication and makes it possible for additional information beyond just the normal process variable to be communicated to/from a SMART field instrument. The HART protocol allows a host application (master) to get two or more digital updates per second from a field device. As the digital FSK signal is phase continuous, there is no interference with the 4-20mA signal. 1.1.3. ASSET MANAGEMENT SOLUTIONS (AMS) SOFTWARE OVERVIEW

AMS software provides an easy-to-use means for integrating various device management software packages into a unified system. AMS operates under the Microsoft® Windows® format. It combines the various device (or asset) management tasks into an application with a common look-and-feel and centralized data storage.

AMS provides access to functionality available via the HART communications protocol for any HART device whose Device Description (DD) is registered with the HART Communication Foundation.

For more information on installation of AMS software, consult the AMS Installation Guide.


1.2. TECHNICAL SPECIFICATIONS 1.2.1. MUX 2700 SPECIFICATIONS

Power Supply 24 VDC nominal [-15%, +25%] Fuse Internal (not user serviceable) Connector Style 2 half pitch 1.27mm 40 pin connectors Environmental Conditions Operating Temperature Range 0 to 55°C (32 to 131°F) Storage Temperature Range -20 to 70°C (-4 to 158°F) Relative Humidity 5 to 90% non-condensing Signal Channels Up to 32 unbalanced signal loops Input Impedance >5000 Ω Communication Port RS-485, differential pair plus GND Communication Speed 9600 or 19200 baud

1.2.2. HPTB TERMINATION BOARD SPECIFICATIONS

Mounting T type (EN50022, DIN46277-3) or G type (EN50035, DIN 46277-1) DIN rail

Connections Power Combicon style 5.08mm removable screw

terminals Field Wiring 5.08mm screw terminals Control Wiring 56 pin ELCO style connector RS-485 Combicon style 5.08mm removable screw

terminals Power Fuse 3.15 A 5x20 Dimensions Length 256 mm (10.1”) Width 125 mm (4.9”) Height 79 mm (3.1”) without MUX,

208 mm (8.2”) with MUX


1.2.3. RS-485 LINE SPECIFICATIONS

Communication Port RS-485, differential pair (isolated) Communication Speed 9600 or 19200 baud Multi-Drop Addressing Up to 31 MUX 2700 modules with 32

channels each Multi-Network Operation Software selectable

Up to 4 serial lines Network Addressing Up to 31 MUX 2700 modules Network Capacity Up to 992 loops SMART Protocol Supported HART Total Number of Bits 11 Number of Data Bits 8 Parity Odd Number of Stop Bits 1 Transmission Type 2 wire

1.3. QUALITY ASSURANCE Pepperl+Fuchs is an ISO9000 certified company and as such all production is performed under a Quality Assurance program following written procedures which are specific for each product family. During the manufacturing, intermediate testing and inspection, and final inspection phases all products are built according to controlled documentation.

Each MUX 2700 unit undergoes accelerated thermic aging (burn-in) for a minimum 200 hours at 50°C (122°F) with at least 1 cooling thermic cycle at 0°C (32°F) and back to 50°C (122°F). The purpose is to identify weak components that may develop initial fault mechanisms due to "Infant Mortality". Only after a positive burn-in test does the MUX 2700 undergo a complete final inspection which is performed with computerized testing equipment specifically developed by P+F for this purpose.

1.4. CERTIFICATIONS AND COMPLIANCE HART Interface Solutions are CE compliant to EN61326

This Equipment is FM approved as suitable for use in Class I, Division 2, Groups A, B, C, and D or non-hazardous locations only. Equipment must be mounted in an enclosure that meets the requirements of ANSI/ISA S82.01 & S82.03 and the National Electrical Code.


2. INSTALLATION 2.1. STORAGE In case of storage of instruments and accessories, proper care should be taken to protect them from any possible damage. Always store instruments in their sealed original packaging until they are installed.

Provide adequate protection to prevent damages that may be caused by exposure to:

• Rain, excessive humidity and/or temperature excursions (inadequate sheltering).

• Dust (build-up of a corrosive patina that may cause oxidations and reduce isolation).

• Aggressive and polluting atmospheres with consequent corrosion.

• Access by insects/rodents (damage of packing or content).

• Mechanical shocks or unauthorized packing opening.

• Intense vibrations (loosening of fastened parts, fatigue failures, etc.).

• Any other possible risk.

Make sure the storage temperature does not exceed the limits of –20 to +70°C (-4 to 158°F) for medium/long term storage (days/months) and -25 to +75°C (-13 to 167°F) for short term storage (a few hours) during transportation or shipment.

2.2. UNPACKING AND INSPECTION Upon receipt of the materials, you should check the integrity of the packing and the contents. In case of damage due to shipping, you should promptly and properly report to the shipper, supplying all necessary information.

If the instruments are not for immediate use, we recommend that you check that all characteristics shown on the instrument’s label meet order specifications (model, supply voltage and frequency, input/output range, certification, tag etc.) as well as the actual application requirements.

If not installed, equipment should be stored following the recommendations of the previous section. 2.3. ENVIRONMENTAL CONDITIONS HIS products, like most modern electronic equipment, can operate in wide temperature and humidity ranges. However, practical consideration suggests a guideline on operating environment for best results.

• Keep operating temperature below 35°C (95° F), ideally between 20°C and 25°C (68 and 77°F), avoiding wide and rapid temperature excursions.

• Control relative humidity within 40 to 60% to avoid risks of static charges or condensation.

• Limit the presence of corrosive atmosphere, fumes and dust, sealing and purifying the control room area and using air filters in the cabinet air intakes (clean cable entry path), if necessary.

• Reduce vibrations (if any) to safe levels.


2.4. INTRINSIC SAFETY The HIS system can interface HART devices located in Hazardous areas by interposition of suitable galvanically isolated Intrinsically Safe Barriers. The barriers must allow bi-directional HART signal communication in addition to the normal 4-20mA loop current processing. 2.5. MOUNTING The MUX 2700 is a plug-in unit that must be inserted in the appropriate termination board position. Exercise care in the insertion to mate the connector's pins, then firmly press the module to engage the connector. Finally, engage the quick lock tabs on either side to secure the module to the termination board.

The HPTB is designed to be mounted on a T-type or G-type DIN rail.

2.6. CABLES HART signals are brought to the MUX 2700 from the field via 5.08mm 3-tier screw terminal blocks designated TB1. The MUX 2700 communicates to the DCS via the ELCO style connectors designated J1-J2. See Table 1 below for channel information.

Table 1 – Connector Function

Field Connector Designation

HPTB/32/TR-AI-01 Analog Input

TB1 Channels 1-32 Control Connector

Designation

J1 Channels 1-16 J2 Channels 17-32


2.7. WIRING The MUX 2700 is a plug-in unit and is connected to the HPTB by two 40 pin connectors. Therefore, all electrical connections (supply, field connections, serial lines, etc.) are made at the termination board unit.

Refer to Figure 1 for a simplified representation of the termination board configuration and the overall outside dimension of the product in inches.

Figure 1 –HPTB Configuration

HPTB/32/TR-AI-01


2.7.1. POWER

Connect 24 VDC to the 2-pin removable terminal at the end of the HPTB. The connector is polarized, so you cannot insert it incorrectly. The polarity is marked on the terminals. A reverse polarity shunt diode and series fuse protection are provided to avoid damaging the module in case of accidentally reversing the polarity connection. In this case, the reverse voltage is clamped at –1.2 V and the fuse blows. Restore correct supply polarity and replace the blown fuse. Be certain to reinstall a good, properly sized, new fuse.

WARNING!

Improper supply connections can seriously damage the instrument and result in risk of fire or explosion in hazardous locations!

DC SUPPLY REQUIREMENTS: The MUX is nominally rated for 24 VDC but will function from approximately 20-30 VDC. The MUX draws a maximum of 100mA from the supply. If the power LEDs fail to light check that the polarity of the supply line is correct.

WARNING!

Note that a crude, poorly filtered or unregulated supply can produce destructive (hundreds of volts) voltage spikes during supply transformer switch-off transient. This could cause minor problems to electro-mechanical components like relays or solenoids but will surely degrade or destroy electronic equipment.

SUPPLY CONDUCTORS SIZING: Since these HIS boards supply power for the AI channels, a single unit can normally require up to 2.56A and its conductors should be sized accordingly. Pepperl+Fuchs recommends 14 AWG or larger wire be used to power this product.

2.7.2. GROUNDING

The HPTB provides an earth terminal lug for connecting the various shield wires to earth. Also included with the HPTB is a DIN rail mountable terminal block. Use of the terminal lug and terminal block for earth grounding will provide the shortest path and best practice for grounding of the HPTB. A 10-14 AWG cable should be secured between the terminal lug and DIN rail block which provides a single point to properly ground field wiring cable shields. This terminal may not be necessary to use if best practice grounding techniques are employed.

The HPTB also provides customer selectable capacitive coupling for the shielding. Setting the shield to be direct coupled or capacitively coupled is accomplished through jumper shunts. Placing the jumper shunt across the pins will bypass the capacitor and direct couple the corresponding shield to earth. Refer to Table 2 for a complete list of the shunts and the associated shield. For best practice any shield should be direct coupled at one end of the circuit.

Table 2 – Shield Configuration

Jumper Shunt # HPTB/32/TR-AI-01 Analog Input

JP1 RS-485


2.7.3. RS-485

An RS-485 network permits up to 32 devices to communicate over a maximum of 1200m (4000 ft) of cable. The length of this network can be extended if necessary by using RS-485 repeaters. The communication occurs via a differential signal over a shielded twisted pair of wires. Per the RS-485 specification the signal wires should be labeled “A” and “B”, but sometimes a “+” and “-“ are used instead. In these cases connect the “+” to “B” and the “-“ to “A”.

NOTE: A MUX 2700 that is cross-wired on the RS-485 network will not be damaged, but it also will not communicate.

Since the MUX 2700 is optically isolated it is important to link the signal grounds of the different network nodes to the host ground through the cable shield. This helps prevent ground potential differences from causing a loss of data or damage to equipment on the RS-485 network.

Many cable manufacturers make cable specifically designed for RS-485 networks. Pepperl+Fuchs Elcon recommends using shielded twisted pair cabling and then utilizing the shield as the RS-485 network ground. This shield should be grounded at the RS-485 converter if possible.

RS-485 wiring must be connected as shown in Figure 2. These wires carry data from the HIS to the PC via an RS-485/RS-232 converter cable. Connect the converter to a serial port on the PC as indicated in the converter’s documentation.

Figure 2 – RS-485 Wiring


2.7.4. FIELD CONNECTIONS

All field wiring is connected via the 3-tier screw terminal block (TB1). To obtain best results from this device the use of shielded cables is strongly recommended and in the case of cable lengths greater than 30m shielded cables are required to ensure proper function of the HPTB. See Figures 3-5 below for specific device connections.

Figure 3 – Loop Powered Transmitters (2-wire)

HPTB/32/TR-AI-01

AB

CField TerminalBlock (TB1)

Transmitter(2-wire)

Shield

Power (+)

4-20mA

Pepperl+Fuchs recommends that all shield drain wires be connected from as close to TB1 as possible to the nearest grounding point and this point be linked to earth by as short a route as possible.


Figure 4 – HPTB Powered Transmitters (3-wire)

HPTB/32/TR-AI-01

AB


Transmitter(3-wire)

Power (+)

4-20mA

Shield

Common



Figure 5 – Self-Powered Transmitters (4-wire)

HPTB/32/TR-AI-01

AB


Transmitter(4-wire)

4-20mA

Common

Shield PowerSupply

The HPTB has one common plane for Channels 1-16 and a second for Channels 17-32. Unless the transmitter has galvanic isolation between its output and power supply the analog loop from the transmitter will link the HPTB common to the transmitter power supply common.



2.7.5. CONTROL CONNECTIONS

The HPTB provides ELCO style connectors (J1-J2) for connection directly to Triconex I/O modules. No adapter or accessory hardware is required. As with field connections it is strongly recommended to use shielded cables should the line length be greater than 30m.

2.7.6. HART COMMUNICATOR

In HART communications, there is one slave (field device) and up to two masters (e.g. Multiplexer, HART Communicator, I/O module). The HART Communicator can be connected to the field side terminals as a secondary master. In the software settings, the MUX 2700 must be the primary master in order to use the HART Communicator.

There cannot be more than two masters. If three or more masters are connected, a primary/ secondary conflict will occur and communications will cease with all devices on that loop. When the MUX 2700 is used with a HART compatible I/O system, the MUX 2700 must be configured as the secondary master. Otherwise, configure the MUX 2700 as the primary master. The HHT is a secondary master by default, and can be connected to the loop when no other device on that loop is configured as a secondary master.

WARNING!

Do not connect the HART Communicator to any Intrinsically Safe field wiring unless the communicator is approved as Intrinsically Safe and is suitable for the actual classification of the specific hazardous location. Also consider the HART Communicator safety parameters and equivalent capacitance and inductance before concluding that you can safely connect it to the I. S. side of the circuit

3. OPERATION 3.1. INITIAL SETUP The default settings for each MUX 2700 are as follows:

Address = 1

Baud Rate = 9600

3.1.1. 2700 SETTINGS

The User Switches buffer has eight inputs from a low profile DIP switch reachable through the front label.

The functions of the switches are as follows:

• Switch 7 (T) Reserved for TEST purposes

• Switch 6 (R1) BAUD RATE 1

• Switch 5 (R0) BAUD RATE 0

• Switch 4 (B4) ADDRESS 4





Further information is given on the front and side labels. In particular, the side label gives the correct setting of every DIP switch combination.


3.1.2. MUX ADDRESSING

The address of the MUX 2700 is determined by the DIP switches as noted above. Each MUX on the same RS-485 network must have a different address, but they do not have to be sequential and do not necessarily need to start at address 1. Possible addresses are 1-31. Address 0 is invalid and cannot be used. Note that network properties of the software setup refers to “multi-dropping.” This refers to multiple MUX 2700s on the same network, not multiple devices on the same I/O loop (also referred to as “multi-dropping”). Multi-dropping should be enabled in the network setup. 3.1.3. BAUD RATE

The baud rate of the MUX 2700 must match the baud rate of the PC Com-Port and the RS-232/RS-485 converter. All three units must have the same baud rate to function properly. The baud rate can be either 9600 or 19200 and is selected as shown on the label located on the side of the MUX unit. 3.1.4. RS-232/RS-485 CONVERTER

An RS-232 to RS-485 converter must be placed between the HIS and the computer’s RS-232 port. P+F recommends the Keithley M2000 converter for non-CE applications. Any standard converter is acceptable, but other models have not been tested by P+F. Alternate brands are available with CE certification.

If only one RS-232 to RS-485 converter is used in setting up the system, then the RS-485 network must be less than 1200 meters (4000 feet). If the network surpasses 1200 meters, an RS-485 repeater must be used. The Keithley M2000 can function as a repeater instead of a converter. The repeater amplifies and retransmits the original RS-485 signal enabling transmission over longer distances. 3.2. START-UP SEQUENCE The proper start-up sequence for the HIS system is as follows:

1. Make all field and control connections to the termination board.

2. Connect RS-485 communications and adjust network settings as appropriate.

3. Plug the MUX 2700 into the termination board.

4. Apply 24VDC to HIS board or power up field devices.

5. After the MUX start-up sequence is complete then initiate AMS.

3.3. CONFIGURATION Each channel of the HIS board can accommodate a SMART device. For details on device wiring please refer to Section 2.7.4. For information on setting the shield jumpers refer to Section 2.7.2. No other configuration is required on the HPTB.

3.4. MUX INDICATORS Three LEDs on the top of the MUX 2700 indicate status. Normal operation is as follows :

• PWR ON – After power is applied the green LED will flash for a period of 15 seconds and then glow solid. The 2700A MUX power LED will not flash. Power is applied to the MUX automatically when it is plugged into the socket on the termination board.

• FAULT – This red LED should not be lit during normal operation.

• HART TX – This yellow LED shows communication with field devices.


3.5. MODES OF OPERATION SCAN MODE - This command sent to the MUX 2700 from the software will instruct the MUX to periodically scan each device automatically. Normally the MUX 2700 will only communicate with a device when instructed by the software. BURST MODE – This command instructs the field device to automatically send information without being commanded to do so. This mode breaks from the normal master-slave relationship inherent in HART communication, but the MUX 2700 will support it when burst mode is selected in the software. 3.6. SYSTEM OPERATION Referring to Figure 6, the heart of the MUX 2700 is the microprocessor. One serial port together with the HART modem generates the physical layer of the HART protocol, while the channel select circuit together with the channel multiplexer links one specific channel (device) at a time. An RS-485 circuit completes the link between the maintenance workstation PC and the field devices. The switch selectable circuit provides information required by the MUX 2700 for initialization and configuration; specifically, the baud rate for communications to the maintenance workstation PC and the MUX 2700 address.

Figure 6 – MUX Operation

USERSWITCHES

HARTMODEM

CHANNELSELECT

MULTIPLEXERChannel 32

Channel 1

SERIAL PORTSRS-485

CIRCUIT

MICROPROCESSOR

From theMaintenanceWorkstation(Through theRS-485/232Converter)

1700 MUX Block diagram

MUX 2700 Block


4. TROUBLESHOOTING 4.1. GENERAL Due to the modular nature of the HIS system, a communication failure may occur anywhere in the data transfer link from the software to the field device. In order to identify where the loss of communication has occurred, it is important to understand which components are working correctly. Often, some simple checks will save hours of troubleshooting. Some of the most common mistakes are: improper wiring connections, baud rate mismatches, improper network settings, and improper addressing of the MUX 2700. 4.2. MUX 2700 The LEDs on the front of the MUX 2700 provide a convenient indication to the user that the MUX 2700 is operational. After the MUX 2700 self-test, the <Pwr On> light should be on, the <Fault> light should be off and the <HART Tx> light may either be off or flashing steadily.

When power to the MUX 2700 is cycled all the lights will come on. Next the green <Pwr On> LED will flash for approximately 15 seconds while the MUX undergoes a self-test. After the successful completion of the self-test the LED will go solid on. For the next 60 to 120 seconds, the <HART Tx> light will flash three times for each channel. During this time, the MUX 2700 is scanning each of the 32 channels. When it is finished, the <HART Tx> LED will either flash steadily or turn off altogether. If you see all of the above occur, the MUX 2700 is operating properly.

Note : The MUX 2700A will behave the same except the power LED will not flash during its self-test.

In addition, the TEST setting on the option switches can be used to gain confidence that the module is functioning. Follow the procedure below to use this feature:

1. With the power off, set the end switch to the TEST position (ON). The module should not be connected to the RS-485 network, the RS-485 address switches have no effect. If an RS-485 terminal is connected to the module, the BAUD rate switches should be set.

2. Turn the power on. The LEDs should light for about 1 second each in sequence (RED, YELLOW, GREEN…).

3. If the LEDs do not flash, there is a fault with the module and it should be returned for replacement.

4. To return to normal operation, remove power to the MUX 2700 and set the TEST switch to the OFF position. Ensure that the correct BAUD rate is selected and that an RS-485 address is set. Then, re-apply power.


If you suspect the MUX 2700 is not functioning properly, please refer to Table 4 below for a summary of some possible problems.

Table 4 – MUX 2700 Troubleshooting

Symptom Cause Solution Lights flash sequentially TEST switch is ON Turn off the power

Set TEST switch off Restart the system

No LEDs lit Power failed or fuse blown Check 24 VDC supply Check <PWR ON> LED Verify fuse intact

Yellow <HART TX> LED continually flashes

Scanning is enabled

Go to the configuration properties of the MUX and disable scanning mode

Red <FAULT> LED is lit Self-test fault Contact Pepperl+Fuchs Technical Support for further instructions

5. MAINTENANCE Pepperl+Fuchs apparatus do not require any particular maintenance under normal operating conditions. They are designed to operate trouble-free and with high stability for long periods.

WARNING!

Any repair made by unauthorized personnel may completely invalidate the safety characteristics of the unit and could void all warranties. Repair not made by Pepperl+Fuchs is fully at user's risk and responsibility. In addition, the warranty terms of the unit will be null and void to all effect.

6. GLOSSARY DCS Distributed Control System

FSK Frequency Shift Keying

HART® Highway Addressable Remote Transducer

HIS HART Interface Solution

HHT Hand Held Terminal

HPTB HART Panel Termination Board

IS Intrinsic Safety

PLC Programmable Logic Controller


7. CONTACT INFORMATION

World Wide Web Website: www.elconhis.com

International Headquarters Europe Pepperl+Fuchs GmbH

Königsberger Allee 87

Mannheim

68307 Germany

Phone: + 49 621 776-0

Fax: + 49 621 776-10 00

Email: [email protected]

Website: www.pepperl-fuchs.com

Regional Headquarters Italy and Mediterranean Pepperl+Fuchs Elcon - Head Office

Via delle Industrie, 4

Mezzago (Mi)

20050 Italy

Phone: ++39 039 6292 1

Fax: ++39 039 6292 290


Website : www.elconinstruments.com

North America & South America Pepperl+Fuchs Inc. - USA Headquarters 1600 Enterprise Parkway

Twinsburg, OH 44087

USA

Phone: +1-330 425 3555

Fax: +1-330 425 4607


Website: www.am.pepperl-fuchs.com

Asia Pacific Pepperl+Fuchs Pte Ltd - Asia Pacific

P+F Building

18 Ayer Rajah Crescent

139942 Singapore

Phone: +65 779 90 91

Fax: +65 873 16 37


Website: www.elconinstruments.com

INSTRUCTION MANUAL

MUX 2700

M U LT I P L E X E R

Instruction Manual 116/GB - PN. 991198 DOC. TEC.

FOR MORE INFORMATIONS, VISIT THE DEDICATED HiS WEB SITE: www.elconhis.com

Stefano Galimberti

MUX 2700 G

Stefano Galimberti

Stefano Galimberti

Stefano Galimberti

a

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IM-ENG-216/GB

WARNING!This manual is copyright by Elcon Instruments. All rights reserved. No part of manual may be reproduced in part or inwhole without express written consent from Elcon Instruments. Elcon Instruments reserves the right to modify manualor any part thereof at its discretion without prior notice.

TABLE OF CONTENTS

1. INTRODUCTION ................................................................................................. page 2

2. UNPACKING AND STORAGE ............................................................................ “ 3

3. FUNCTIONAL DESCRIPTION ............................................................................ “ 43.1 Overview .................................................................................................... “ 43.2 Operation ................................................................................................... “ 63.3 LED indications ......................................................................................... “ 63.4 Power-up sequence ................................................................................... “ 63.5 Application guidelines ................................................................................ “ 73.6 Hardware architecture ................................................................................ “ 73.7 Software architecture ................................................................................. “ 8

4. HART INTERFACE SOLUTIONS OVERVIEW .................................................. “ 94.1 Presentation ............................................................................................... “ 94.2 1132/CON solution .................................................................................... “ 104.3 2108/64 HART D solution .......................................................................... “ 114.4 I.S. Integrated solutions (Mux2700G with HiD2000 Intrinsic Safety interfaces) .. “ 124.5 Electrical connections ................................................................................. “ 12

5. MAINTENANCE WORKSTATION OVERVIEW .................................................... “ 135.1 General ...................................................................................................... “ 135.2 Software packages .................................................................................... “ 13

6. MUX2700G SPECIFICATIONS .......................................................................... “ 146.1 General ...................................................................................................... “ 146.2 Mechanical ................................................................................................. “ 146.3 Supply port ................................................................................................. “ 156.4 Signal port (HART) ..................................................................................... “ 156.5 Serial Port (RS-485) ................................................................................... “ 15

7. INSTALLATION AND CONFIGURATION ............................................................. “ 177.1 Operating environment .............................................................................. “ 177.2 DIP-switch configuration ............................................................................ “ 177.3 Connections and mounting ........................................................................ “ 197.4 Final checks ............................................................................................... “ 19

8. MAINTENANCE AND TROUBLESHOOTING ...................................................... “ 218.1 Maintenance .............................................................................................. “ 218.2 Power-up self-test procedure ..................................................................... “ 218.3 Additional troubleshooting .......................................................................... “ 21

9. QUALITY MANAGEMENT POLICY.................................................................... “ 22

10. WARRANTY..................................................................................................... “ 23

11. ACRONYSM .................................................................................................... “ 24

12. APPENDIX A: MUX2700G ISOLATION STRUCTURE ................................... “ 25

FOR MORE INFORMATIONS, VISIT THE DEDICATED HiS WEB SITE: www.elconhis.com

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IM-ENG-216/GB

1. INTRODUCTION

This manual is intended to provide guidance for the installation, operation and maintenance of the Mux2700G HARTSignal Multiplexer (HSM) module. To avoid damage, failure or improper operation the contents of this manualshould be read and understood before installing and operating the instrument.

The Mux2700G HSM is a compact, plug-in module which is able to accept up to 32 HART channels and to feed theminto a single, faster communication line, which is in turn to be connected to a suitable Maintenance Workstation.

The Mux2700G module is intended for use as part of the Elcon HART Interface Solutions (H.I.S.), which providesappropriate interconnection packages for various applications. H.I.S. makes available a wide set of TerminationBoards – with or without integrated isolators – to support different applications and to directly interface with themain PLC/DCS equipment. The Mux2700G is simply to be inserted in the selected board to get full HART access tothe relevant field devices while preserving the traditional 4/20 mA analogue loop interfaces.

The Mux2700G use the same effective and compact enclosure of the successful HiD series, including the innovative“Quick Lock” mechanism to easily insert/remove the unit from the Termination Board without the need for any tool.

Key features summary:

• low power consumption , very small size;• compact and proven HiD enclosure, “Quick Lock” capability;• high noise immunity, industrial-level EMC compliance;• two DC-blocking capacitors – non-polarised type – on each signal loop;• optimal mechanical integration with other HiD solutions;• fully compatible with existing Mux2700 solutions;• very low loop-interference risk (SIL-3 rating)

Warning !

The Mux2700G unit is not certified for intrinsically safe applications and must not be used to directly interfacewith hazardous-area located field devices. In fact, some H.I.S. solutions do allow the mounting of the Mux2700Gon the same board where intrinsically safe isolators are located. In this case, the safety-related application areasmust be addressed by trained personnel which is fully acquainted with the principles of intrinsically safe system.Elcon Instruments has published a complete tutorial entitled “Guide to Intrinsic Safety” covering most aspect ofintrinsic safety. The book can be obtained from Elcon Instruments free of charge.

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2. UNPACKING AND STORAGE

Upon receipt of the materials, you should immediately check the integrity of both packaging and contents. In caseof damage due to shipping, the receiver should promptly and properly report to the shipper supplying all necessaryinformation.

If the instruments are not for immediate use, a check is recommended about the compliance of the units specifica-tions (as indicated on the label) with both order specifications and with the actual application requirements.

In case of storage of instruments and accessories, proper care should be taken to protect them from any possibledamage. Always store instruments in their sealed original packaging until they are installed. In addition, adequateprotection should be provided from:

• humidity and temperature excursions outside the specified range;• aggressive or polluting atmospheres (e.g. SO2, H2S, mists, salts, smokes, dusts);

• access by insects/rodents that could damage packaging or content;• mechanical shocks or intense vibrations.

IM-ENG-216/GB

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3. FUNCTIONAL DESCRIPTION

3.1 Overview

The Mux2700G HART Signal Multiplexer (HSM) provides 32 signal channels for connection to field located, “smart”transmitters or control devices supporting digital communication according to the HART standard. The Mux2700Gacts as a gateway between a Maintenance Workstation (MW) – typically a PC with suitable SW – and the fieldinstrumentation. The MW connects, in a multi-point configuration, with up to 31 Mux2700G using a fast RS-485 com-munication channel.

The HART protocol is a widely accepted technique by which standard 4/20 mA field devices can support digitalcommunication for configuration and maintenance purposes. A modulated, audio-frequency signal (Bell202 FSK) isin fact superimposed to the analogue current loop providing a 1200 baud, half-duplex communication capability.The HART protocol, being a widely accepted standard specified up to the application layer, permits an effectiveintegration, at the Maintenance Workstation level, of field devices from different manufacturers.

The Mux2700G HSM not only uses the HART protocol to communicate with the field devices but also to interfacewith the Maintenance Workstation via an RS-485 link. In this way, an highly standardised solution is obtained.

Under the supervision of the Maintenance Workstation, the Mux2700G interrogates each field device, retrieving infor-mation which are then stored in an internal data-base. This internal data-base can then be accessed in real-time bythe MW which however, when required, can also directly communicate with any specific field device.

IM-ENG-216/GB

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IM-ENG-216/GB

1

up

to

32

1

up

to

32

1

up

to

32

ToDCS - PLC I/OCARDS(To Control Room)

TERMINATION BOARD

RS 485

FROMFIELDDEVICES

SUPPLY

1

up

to

32

1

up

to

32

1

up

to

32

1

up

to

32

1

up

to

32

MUX2700

MUX2700

MUX2700

MUX2700

MUX2700

MUX2700

Model

2116/HAT/

1

up

to

32

1

up

to

32

1

up

to

32

1

up

to

32

1

up

to

32

Model2116/HAT/

Model

2116/HAT/

Model

2116/HAT/

Model

2116/HAT/

CONTROL ROOMDCS/SCADA SYSTEM

(Har t or Non HartCompatible)

HHC

1 up to 32 1 up to 32 1 up to 32

PORTABLENOTEBOOKor LAPTOP

TANKFARM

PCU # 1CATALYTIC CRACKER

PCU # 2BOILER

To FurtherBoards

NON HAZARDOUS LOCATION

NON HAZARDOUS LOCATION

P.C. MAINTENANCE WORKSTATION

PCU # 3 REFORMER

ZONE 2II B

• Hazardous Non Hazardous Locations of Smart Instruments• Local or Remote Instruments Maintenance• Suitable for Existing Smart Field Device Transmitter, Valves, Mas Flow• Multiple• Independent to DCS System• ISO 9000 Reporting

RADIOMODEM

RADIO MODEMUHF Microwave

ZONE 1II B

ZONE 1II C

ZONE 1II C

To FurtherBoards

MUX 2700G

Remote instrumentmaintenancemonitoring forunmannedplatform orremote site

To FurtherBoards

To FurtherBoards

Model2116/HAT/

FIG. 1

- 6 -

3.2 Operation

The Mux2700G HSM module implements HART protocol commands and acts as a gateway device between theMaintenance Workstation (MW) and the field devices. It responds to commands received from the MW (RS-485interface) as a slave device and issues commands to the HART slaves (field channels) acting as either a Primaryor Secondary Master (according to the HART specification).

A modified version of the HART protocol was implemented on the RS-485 physical layer to obtain a fast and relia-ble communication with the Maintenance Workstation. In this way, standard HART messages can be used by theMW for an effective, seamless integration of field devices from different manufacturers.

The Mux2700G can continuously poll each connected field device the get the specified primary (or secondary) HARTvariable, automatically updating the internal data-base. This is called scan operation, and can be enabled or disa-bled by the Maintenance Workstation (the Mux are factory set in the “Scan-Off” condition). When in the “Scan-On”mode, the MW can generate a warning message whenever a field device stop communicating (e.g. because it isdisconnected from the loop).

At power-up, the Mux2700G always performs a locate activity, that is to say, it polls all the 32 channels to find anyconnected – and communicating – field device and to rebuild the required, internal access tables. The locate acti-vity can be started also by the Maintenance Workstation, and this is usually required to be able to communicatewith a new field device connected to the Mux after power-up. The locate time can range from 15 to 60 seconds,depending on the specified retry counts (the Mux are factory set with a retry count = 3, resulting in around oneminute of locate time).

In addition to providing access to the HART-capable field instruments, the Mux2700G module is itself, in all respect,an HART device with parameters and internal functions available to the user (e.g. Tag, Description and unique DIN– Device Identification Number).

3.3 LED indications

The information provided by the Mux2700G LED (mounted at the panel front) is summarised in the following table:

3.4 Power-up sequence

In the following, the normal Mux2700G power-up sequence is described. This is always the standard power-upbehaviour, unless SW8 (at the panel front) is set into the Test position.

• Immediately after power-up, the 3 LEDs goes immediately On, and remains in this state for around 3 seconds.

• An internal self-test is then performed and, if any problem is detected, the Red LED goes fixed On. (during the self-test - which lasts around 8 seconds - the Green LED keeps blinking).

• The Yellow LED then start blinking, indicating that the Mux2700G is performing the locate activity, that can lastup to around one minute.

• The Yellow LED should then go Off, unless the scan operation is enabled or the Maintenance Workstation isdirectly communicating with a field device.

IM-ENG-216/GB

Colour Name FunctionYellow HART TX ongoing HART communication with field devices

Green PWR ON supply indicator (can blink at power-up)

Red FAULT internal fault indication (power-up detection only)

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3.5 Application guidelines

The Mux2700G HSM is not normally intended to be designed by the user in a specific application, but to be used aspart of the Elcon HART Interface Solutions (H.I.S.) offering, which provides appropriate interconnection packagesfor a wide range of applications, as well as a set of compatible Maintenance Workstation solutions. This makes theMux2700G application straightforward, because most “tricky” interface and compatibility issues have already beensolved, and a ready to use, plug-and-play solution can be provided.

As an example, when “HART filters” are required to ensure the compatibility with a specific PLC/DCS, these areusually directly integrated at the H.I.S. level.

However, there can be situations, as with “general-purpose”, screw-terminals H.I.S. boards, in which some care inwiring and installation is required to set-up a working system. An overview of some H.I.S. solutions is presented insection 4., please also refer to the relevant H.I.S. documentation for more information.

As a general guideline, it is worth noting that the Mux2700G input channels must be connected across the 4/20 mAloop in such a way as to see parallel resistance not lower than 200 Ω (250 Ω recommended). If this is not the case,the available HART signal could be too week to guarantee a reliable communication. A problem of this type can befound with an analogue-input card with a low internal current-sense resistor, or with any loop-connected devicethat, in spite of having an high DC resistance, presents too low an impedance on the 4/20 mA loop at HART fre-quencies (1200 / 2200 Hz).

In addition, it is always recommended to connect the “+” input terminal at higher DC voltage level with respect tothe “–“ input terminal (that will be in many cases at a GND level).

3.6 Hardware architecture

The heart of the Mux2700G HSM module is the microprocessor (CPU). One CPU serial port – together with theHART modem and the related analogue circuits – implements the physical layer of the HART protocol. A secondCPU serial port is used to drive the opto-isolated RS-485 interface.

The internal architecture of the Mux2700G Multiplexer is depicted in the following block diagram of Fig. 2. As you cansee, the HART modem is multiplexed on the 32 available field channels to get a cost-effective and compact solu-tion.

IM-ENG-216/GB

POWER

SUPPLY

UNIT

+24V

RS-485

INTERFACE

OPTOISOL.

CPU

MUX

A

HARTMODEM

+

+

A1

A3

SCREEN

A4,A5,A6

A31A

A30B

A32

2.2µF

0.68µF

2.2µF

0.68µF C32

B32

C1

B1

CH1

CH32

FIG. 2

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A full three-port isolation is also provided. The power supply section is in fact galvanically isolated from both theanalogue multiplexing section and from the RS-485 serial line.

Each input channel is also DC-isolated from the input GND by two non-polarised capacitors. The dual capacitorsolution, usually not to be found on comparable products, avoid the need of having a single common ground for allinput signals. In this way, it is also possible to connect to any “floating” loop without any loss of isolation

In general, the three-port isolation combined with the dual-capacitor approach result in an effective and reliablesolution, with such advantages as:

• undesired ground loops can be easily avoided;• existing isolation between different ports can be preserved;• very low risk of disturbing the 4/20 mA loop signal, also in case of fault.

I fact, the Mux2700G architecture is such that any internal single fault never result in any interference with an inputconnected 4/20 mA loop. For this reason, the Mux2700G can be used as a monitoring device within safety-sensitiveapplications.

3.7 Software architecture

The Mux2700G HSM is not normally intended to be designed by the user in a specific application, but to be used aspart of the Elcon HART Interface Solutions (H.I.S.) offering, which includes a set of compatible MaintenanceWorkstation solutions.

This means that the user doesn’t have to worry about either the internal details of the unit software functions norabout the specific RS-485 protocol features. In fact, the Maintenance Workstation software make most of thesedetails “invisible” to user by providing an user-friendly, graphical man-machine interface.

When you have any special need or problem, please contact Elcon for additional information.

IM-ENG-216/GB

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4. HART INTERFACE SOLUTIONS OVERVIEW

4.1 Presentation

HART Interface Solutions (H.I.S.) makes available a wide set of Termination Boards to support different applica-tions. There are several styles of interconnection methods available for mounting of the Mux2700G to suit the variousdemands of particular installations.These satisfy the basic requirements of:

• general purpose wiring interconnection;• replacing the function of existing control system termination panels;• including Intrinsic Safety isolating interfaces.

The details of specific applications can be found in the support documentation for the HART Interface Solutions(H.I.S.) panels which are custom designed to satisfy these particular needs.

However, the following sections give details of three generic solutions for the mounting of the Mux2700G which areincluded to show the scope of these possibilities:

• single Mux2700G mounting on termination panel: 1132/CON-8-H-DS• multiple Mux2700G mounting on termination panel: 2108/64-HART-D• Mux2700G integrated with HiD 2000 IS interfaces: 2116/HAT/SACON-HART

IM-ENG-216/GB

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IM-ENG-216/GB

4.2 1132/CON solution

281 mm

255.5 mm

COMMONSHD

GNDBolt

RS 485

FIELD CONNECTIONTERMINALS

I.A.C. (INTERFACE ADAPTORCARDS CAPABILITY)

DC

SUPPLY

TERMINALS

SHD

1

SHD

2 SPAREFUSE

JP (1 to 31)or FUSE

JA(1 to 32)

JB(1 to 32)

JP (2 to 32)or FUSE

Selecting Different Input Connections Arrangements

1) LOOP SUPPLY TRANSMITTERS (non individually fused 3) 4-20mA FROM FIELDinputs) - Install JPA on position 3- Install jumper JP - Install JPB on position 1- Install jumper JPA and JPB on position 3 - Connect 4-20mA inputs at terminals - Connect Tx at terminals +24V (positive) and C (negative) C (positive) and B (negative)

For individually fused loop supply Tx plug TR5 50mA valuefuses in place of JP jumpers (connections remains the same) 4) I/P SMART

- Install JPA on position 12) 1-5V FROM FIELD - Install JPB on position 1

- Install JPA and JPB on position 1 - Connect I/P at terminal C (positive) and- Connect inputs at terminals C (positive) and B (negative) B (negative)

FIG. 3

- 11 -

4.3 2108/64 HART D solution

IM-ENG-216/GB

Elcon I.S. Termination Panelwith pick-off for HART signals (example)

16 channels

16 channelsTo RS485/RS232

converter

24 Vdc

General purpose1-5 V HART signal inputs

(PHOENIX VARIOFACE style)

T.B. type 2108/64 HART D(total 64 ch.)

16 channels

16 channels

FIG. 4

4.5 Electrical connections

All H.I.S. electrical connections and wiring should comply with the standards and installation rules (e.g. ISARP12.6) applicable in the country of use.

Before powering the Termination Board, verify the polarity and the voltage level of the supply line. The supply volta-ge must be within the limits specified for the Mux2700G module.

Warning !Improper supply connections could seriously damage the Mux2700G module.

- 12 -

4.4 I.S. Integrated solutions (Mux2700G with HiD2000 Intrinsic Safety interfaces)

IM-ENG-216/GB

I.S. FIELD TRANSMITTERSAND VALVES

on Board Mux2700G (up to 32 ch.)

HiD 2026

IN Ch. 1

INCh. 2

J10

HAZARDOUS AREAField

SAFE AREAIntrinsic Safety & Termination Cabinet

DCS I/O

~

~

F

F

~

~

F+ 2

5

+ 1

4 14

+11

15

+12

to DCSupplyBus

+GNDAB

RS485(duplicated)

24 Vdc24 Vdc PS1+

PS2+

DCSupplyBus

1-5 Volts

CL 6825

16 AI

MUX 2700G Multiplexer

LOOP DIAGRAM (Example of an I.S. integrated solution)

FIG. 5A

FIG. 5B

- 13 -

IM-ENG-216/GB

5. MAINTENANCE WORKSTATION OVERVIEW

5.1 General

A Maintenance Workstation (MW) is to be connected to the installed multiplexers to implement the required, HART-related configuration and supervision activities. In fact, the Mux2700G basically acts as a gateway between the fielddevices and the MW.

The Maintenance Workstation is typically made of a suitable software package loaded on a standard desktop PCequipped within external RS-232/RS-485 converter. The recommended operating system is Windows NT, butWindows98/95 is also generally supported. As for required PC features, please refer to the documentation of theapplicable MW software package.

At least one free serial communication line (RS-232) must be available on the Maintenance Workstation to connectthe 232/485 converter. Most MW software packages generally permit the usage of more than one serial line (withadditional 232/485 converters) to increase the total number of accessible field devices.

Up to 31 Mux2700G modules can be connected to a single RS-485 serial line, for a total of 992 accessible field devi-ces. The Maintenance Workstation is usually able to support more serial lines, so it is possible to effectively mana-ge a few thousands of field devices without problems.

The recommended RS-232/RS-485 converter is the MD44 model (Westermo). Other equivalent devices can befound on the market (e.g. from Keithley) but it is better to check their compatibility with the specific MaintenanceWorkstation software.

5.2 Software packages

Several PC software packages are available which include support for the Elcon Mux2700G HSM.

Asset Management Solutions (AMS) from Fisher Rosemount, (www.frco.com/fr/solutions/ams) is a scalable softwa-re product with full HART abilities, and functionality can be added as required. The “engine” of AMS is the FieldServer which provides access to HART information from any device with a common user interface and supports acommon database. The Universal System Interface is the software driver for an online link from the Field Server tothe Elcon Mux2700G. Additional “snap-on” application packages are available for configuration, calibration, mainte-nance, valve diagnostics etc. to suit customer needs.

Valvelink from Fisher Controls (www.fisher.com) provides an easy-to-use environment for configuring, calibratingand diagnosing the operating characteristics of Fisher Fieldview instruments such as valve controllers and transdu-cers.

Applied System Technologies Cornerstone family of products is a comprehensive package useful for commissio-ning, calibration and maintenance management of industrial instruments both in the lab and in the field.Cornerstone products provide multi-vendor support for all types of HART compatible smart instruments.Cornerstone creates and maintains a comprehensive instrument database and individual histories of the configura-tion, test, calibration and maintenance activities performed on each instrument.

Finally, Field Browser from Neles/Metso Automation is another package which can directly interface with theElcon Mux2700G HSM.

For details about these software packages please refer directly to the supplier mentioned.

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IM-ENG-216/GB

6. MUX2700G SPECIFICATIONS

N.B.: all values are typical unless otherwise specified.

6.1 General

6.2 Mechanical

Operating Temperature: 0 to 55 °C (32 to 131 °F)

Storage temperature: -20 to 70 °C (-4 to 158 °F)

Relative humidity (non condensing): 5 to 90 %

EMC: EN50081-2, EN50082-2

Isolation (Supply port to Signal port): 1400 Vac, rmsIsolation (Supply port to Serial port): 1400 Vac, rmsIsolation (Serial port to Signal port): 500 Vac, rms

CE marking carried

Dimensions: see drawing

Case: HiD style, Policarbonate

Mounting: plug-in on Termination Board (no tool required)

Protection class: IP30

Connectors: 2, plug-in, 40-poles miniature connectors

Hot-plug in: supported

Unit weight: about 140 grams

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IM-ENG-216/GB

6.3 Supply port

Supply voltage: 24 Vdc (-15%, +25%)

Supply current: 20 Vdc 32 mA (typical, RS485 quiescent)

24 Vdc 28 mA (typical, RS485 quiescent)

30 Vdc 23 mA (typical, RS485 quiescent)

Protection: internal fuse, not user-serviceable

6.4 Signal port (HART)

Channel number: 32 signal loops

DC-isolation: dual-capacitor isolation on each loop

Allowed common mode voltage: up to 30V

Differential mode clamping: +/- 5.2V (for transient or AC signals)

Receive signal range: 0.12 Vpp < signal < 1,5 Vpp

Receive impedance magnitude: > 5000 ΩCarrier Detect levels: signal > 0.12 Vpp — CD asserted

signal < 0.080 Vpp — CD not asserted

Transmit signal amplitude : 200 mV (200 Ω load, typical)500 mV (500 Ω load, typical)

200 Ω load — 150 mV < signal < 250 mV

Carrier stop time < 10 bit time

Device connection type: DC-isolated bus device

Impedance level type: High Impedance device

Data link type: Primary or Secondary Master (configurable)

Field multi-drop support: available on request

For additional, more detailed HART-related specifications, please refer to the HART FSK Physical LayerSpecification Rev.8.0 available from the HART Communication Foundation (HCF_SPEC-54), which the Mux2700Gmodule is generally compliant with.

Notes :

• To minimise input capacitors size and to get an higher output signal level, the Hart signal transmit section is basedon a current generation technique. For this reasons, the output signal level is proportional to the external load,which should not exceed 500 Ω to avoid possible cross-talk or saturation problems.

• The specified transmit-signal amplitude is a DC value measured at the centre of a waveform semi-period.

• To maximise allowed cable length and to avoid noise problems, you should avoid to connect to the MUX HARTlow impedence devices < 250 Ω.

6.5 Serial port (RS-485)

Line type: RS-485, differential pair plus GND

Line speed: 9600 Baud, 19200 or 38400 Baud

Line topology: multi-point, master-slave connection

Device type: slave (up to 31 slave Mux can connected to a single master)

Slave addressing range: 1 to 31 (0 reserved)

Protocol type: H-Port (HART based)

Master device: Maintenance Workstation (MW)

Warning !

A suitable RS-232 to RS-485 converter is required to connect the port with a standard PC (see Fig. 6).As for RS-485 line detailed specifications, please refer to the relevant standard.

- 16 -

IM-ENG-216/GB

HARTPROTOCOLAND 4-20mA

RS-232ModemCable

AB

GND

AB

B

GND

AGND

to DCS

to DCS

24 Vdc

CABLE PINASSIGNMENT

2 TX3 RX5 GND

Female DB9connector

Pin No.

Female DB9connector

Pin No.

OPTIONAL DB9 toDB25 ADAPTER

2 TX3 RX5 GND

DB9Pin No.

DB25Pin No.

2 TX3 RX5 GND

3 TX2 RX7 GND

PCHOST STATION

RS 485SHD

1

SHD

2 SPAREFUSE

RS-485Connections

RS-485Connections

RS-485Connections

WESTERMO switch settingsSee the Westermo Mod. MD-44 DCinstruction manual for details

19200/9600

11

2-wire

No termination

Selection of data rate

Selection of bits(8 bits odd parity - 1 stop bit)

Transmission

Termination

S2

S2

S2

S3

1-2-3

4-5

6-7

1-2-3-4

switch bit

+

RS-232 INRS-485 IN RS-485 OUT

Supply LineCord

ABGND

to PCHOST STATION

54321

9876

FIG. 6

- 17 -

IM-ENG-216/GB

7. INSTALLATION AND CONFIGURATION

7.1 Operating environment

The Mux2700G HART Signal Multiplexer module rate on wide temperature and humidity ranges. It is however desira-ble to limit the environmental stress, so to maximise the expected life time. It is therefore recommended not to ope-rate the unit near the specified high-temperature limit for long periods of time.

In addition, you should remember that high humidity (above 60%), when in conjunction with corrosive atmosphereand/or temperature stresses, can result in corrosion, with bad effects on connectors contact quality.

The Mux2700G HSM was carefully tested according to the specified EMC (electromagnetic compatibility) standards.The verifications were either carried out by certified test houses or internally by using equivalent test set-ups.Comprehensive reports were always used to register test results.

The compliance with the relevant standards is not however such to always guarantee the proper unit behaviourregardless of the operating environment and of the specific system configuration. The following guidelines are use-ful minimise this type of risk:

• all system units should carry the CE mark and comply with the related EMC standards;• when a strong RF noise is expected, use screened and rly grounded I/O cables;• don’t run I/O cables side by side with potentially noisy system wiring;• avoid ground loops as much as possible and use proper grounding end earthing techniques.

7.2 DIP-switch configuration

The configuration DIP switches located at the top of the unit as shown in the following drawing. (Fig. 7a-7b and theaddress setting tables at page 18).

PWRON

MUX

2700G

FAUL HART TX

BAUD RATERESERVED

ADDRESS

SW1SW2SW3SW4SW5SW6SW7SW8

ON OFF

FIG. 7A FIG. 7B

MUX2700G

ELCON INSTRUMENTSI N T R I N S I C S A F E T Y a n d S P E C I A L I S T S

Ch.1

RS-485SERIAL LINE

Ch.32

HART ® DEVICES

B

A

GND

I

P

I

P

+

• Address setting

The Mux2700G module operates as a slave device on a multi-point RS-485 serial line. A unique address is thereforeto be specified for each Mux connected to the same serial line. To set the required address, use the first five swit-ches according to the following table. Please note that the address 0 is reserved and is never to be used.

- 18 -

IM-ENG-216/GB

RS-485 ADDRESSSW1 SW2 SW3 SW4 SW5

0 OFF OFF OFF OFF OFF

1 ON OFF OFF OFF OFF

2 OFF ON OFF OFF OFF

3 ON ON OFF OFF OFF

4 OFF OFF ON OFF OFF

5 ON OFF ON OFF OFF

6 OFF ON ON OFF OFF

7 ON ON ON OFF OFF

8 OFF OFF OFF ON OFF

9 ON OFF OFF ON OFF

10 OFF ON OFF ON OFF

11 ON ON OFF ON OFF

12 OFF OFF ON ON OFF

13 ON OFF ON ON OFF

14 OFF ON ON ON OFF

15 ON ON ON ON OFF

16 OFF OFF OFF OFF ON

17 ON OFF OFF OFF ON

18 OFF ON OFF OFF ON

19 ON ON OFF OFF ON

20 OFF OFF ON OFF ON

21 ON OFF ON OFF ON

22 OFF ON ON OFF ON

23 ON ON ON OFF ON

24 OFF OFF OFF ON ON

25 ON OFF OFF ON ON

26 OFF ON OFF ON ON

27 ON ON OFF ON ON

28 OFF OFF ON ON ON

29 ON OFF ON ON ON

30 OFF ON ON ON ON

31 ON ON ON ON ON

• Baud-rate setting

The next two switches permit to set the desired serial line baud-rate. The same baud-rate must be set also on the RS-232/-RS-485converter and on the PC RS-232 serial line. Please note that theremaining SW6/7 configurations are reserved and never to be used.

RS 485 BAUD RATESW6 SW7

9600 OFF OFF19200 ON OFF

• SW8 settingThe SW8 switch must be always set to OFF and its reserved for factory-test usage.

Stefano Galimberti

38400 OFF ON

Stefano Galimberti

OFF

- 19 -

IM-ENG-216/GB

7.3 Connections and mounting

The Mux2700G HSM module is a plug-in unit intended for insertion in a suitable H.I.S. Termination Board.Therefore, the primary electrical connections (supply, field connection, serial lines) are made at the TerminationBoard level. Please refer to the relevant board instruction manual for details.

The Mux2700G box – unlike other HiD-type enclosures – is not mechanically polarised because its different connec-tors avoid the possibility of wrongly inserting it in an isolator slot. No polarisation prong is therefore to be found onthe bottom of the enclosure.

To mount a new Mux2700G module on the board, proceeds as follow:

• identify the right Mux2700G slot by consulting the relevant documentation;• carefully align the unit connectors with the board ones, then gently press down module; • push down the yellow tabs on each side of the module to firmly secure it to the panel.

To remove an installed Mux2700G, simply lift the yellow tabs and gently unplug from the panel.

The Mux2700G Multiplexer is an hot plug-in capable module therefore, when required, you can mount it withoutdisconnecting the power from the relevant Termination Board. At plug-in time, no relevant disturbance is to beexpected on 4/20 mA field signals. Before powering up the unit for the first time, please remember to carefullycheck supply voltage level and polarity.

When required, “tag labels” are available to be inserted on the transparent lid located at the top of the module. Thiscould be useful for general identification purposes.

Mux 1700 note:

The Mux2700 Multiplexer module is a fully functional replacement for the earlier Mux1700 module. The Mux2700can be fitted to any Termination Board designed to accept the Mux1700 by the usage of the proper mounting adap-ter, plugged onto the existing MUX2700 connector and them to be ordered separately with code MUXADAPT 27/17(PN 985845).

The adapter should be first screw-fixed on the Termination Board (screws included). The Mux2700 can then bemounted onto the adapter following the previously described procedure.

7.4 Final checks

Before applying power and putting the Mux2700G module into operation, carefully check the following:

• On termination board- supply connections, voltage level and polarity- field wiring polarity and tags- serial line (RS-485) wiring, with special care to polarity

• On Mux2700G module- RS-485 address (between 1 and 31)- RS-485 baud rate (9600,19200 or 38400)- SW8 position, (OFF)

• On RS-232/RS-485 converter- baud rate (9600,19200 or 38400)- RS-485 connections, with special care to polarity- RS-232 and supply connections

• On Maintenance Workstation: - proper software installation and configuration- baud rate (9600, 19200 or 38400).- RS-232 line operation and connections

Stefano Galimberti

- 20 -

IM-ENG-216/GB

Warning !

Please remember that – unless the GND signals at both ends are connected to earth – the RS-485 communicationline needs three wires (differential pair plus GND). It is not recommended to use the cable shield as GND connec-tion (i.e. third wire).

Warning !

Improper supply connections could seriously damage the unit.

RS-485 note:

According to the RS-485 standard you can connected up to 32 devices to a single line of up to 1200 meters (whenyour data rate is lower than 100K baud). To get a reliable connection we recommend not to exceed this limits. Youshould also verify that the connection cable is compliant with the standard specified requirements (but at low data-rates you don’t generally have any problem). Finally, don’t forget that for an RS-485 line a suitable termination resi-stor is required at both ends, and you should switch it On both on the RS232/RS485 converter and on the farthestTermination Board panel (i.e. on the last device on the RS-485 bus).

- 21 -

IM-ENG-216/GB

8. MAINTENANCE AND TROUBLESHOOTING

8.1 Maintenance

No periodic maintenance or calibration is required for this product, which is also not intended for direct repair fromthe end-user. For these reasons, the Mux2700G enclosure was not designed to be easily opened (and a special toolis in fact required at this purpose).

Warning !

Any attempt to open the unit or to directly repair it will make the warranty null and void.

8.2 Power-up self-test procedure

This the first recommended check when there is any doubt about proper Mux2700G operation.

• When the Mux2700G is powered, the three LEDs should light for about 3 seconds. If, after this time the redLED remains fixed in the On status, the unit should be returned to Elcon for repair.

8.3 Additional troubleshooting

When the unit pass the power-up self-test and there are still operational problems, try the following checks:

• Verify the power-up sequence – as described in section 3.4 – to get more information about the situation.

• Repeat the checks described in section 7.4 to identify possible problems.

• When you have signal level problems, verify that the equivalent, parallel network resistance is at least 200 Ω(250 Ω recommended) as required by the Hart specifications.

• When the communication with the Maintenance Workstation is OK but you can not communicate with the fielddevices, check with an oscilloscope the Hart signal level and noise content on the loops.

• With a relevant noise present at the Hart signal level – and when it is not viable to reduce it in any other way –you can consider the increase of the loop series resistance up to 500 Ω (when compatible with the DC 4/20 mAloop requirements). In this way, the Hart signal level double, as well as the signal-to-noise ratio

Note:

Elcon technical support is available to advise about special problems or unclear situations. Please always contactElcon before returning any suspected defective unit, either in warranty or not.

- 22 -

IM-ENG-216/GB

9. QUALITY MANAGEMENT POLICY

The Elcon mission is to guarantee the highest standards of Quality for the products and services offered and inElcon “Quality” means to keep up with customer expectations and to assure the customers’ satisfaction. In practice,the products must conform with specifications, defects must be prevented and the costs due to non conformancemust be reduced.

In order to achieve these targets Elcon has enlarged the concept of “Customer” and introduced the concept ofCompany internal Customer. In this way all those persons that within the Company benefit from other people’swork or service are considered as if they are the Customer Elcon considers Total Quality as one of the fundamen-tal factors in achieving its mission. At Elcon the two key elements of Total Quality are “Quality System and“Continuous Improvement”.

The Elcon Quality Assurance System is the set of organisational structure, responsibilities, procedures, proces-ses and resources for implementing Quality management. Elcon has adopted the standard EN ISO 9001 as refe-rence for its own Quality System. In accordance with this choice our key suppliers also have to comply with aQuality System conforming to the EN ISO 9000 standard.

This Quality System guarantees confidence in Elcon capability to supply the required Quality and at the same time,it ensures that Elcon maintains Quality at an optimal cost. Elcon products satisfy Customers and meet the specifi-cations and rules of international standards. Safety, performance, reliability, product documentation and truth inadvertising are the basic principles of product Quality.

Quality in Services is a factor of growing importance to achieve market penetration and Elcon considers serviceas an integral part of the Customer package and checks continuously that its services meet Customer’s require-ments.

Constant improvement is the foundation of Total Quality. Elcon continuously ensures that the performance of pro-ducts, services, management and the Quality System, meet customer requirements. Improvement can only beobtained with the active participation and involvement of all personnel and therefore Elcon management recognisesthat the human resources of the company play a vital role in the achievement of its objectives.

- 23 -

IM-ENG-216/GB

10. WARRANTY

• General

Elcon Instruments certifies that all the instruments of their manufacture are immune from defects or loss of es-sential quality, and whenever they are apparatus, Elcon also guarantees proper operation. The duration of the war-ranty period is indicated in the order confirmation and starts from the date of delivery or on site test (if required).Unless otherwise specified the warranty is of 12 months, from delivery date.

The action due to the customer for vices, defects, or loss of quality is subject to the terms of articles 1495,1497C.C. (Italian Civil Code). The denunciation of the, defect or quality loss must be made by the customer by registe-red mail, telex, fax, or equivalent written form to be sent to the main office of Elcon Instruments.

• Limits - burdens - obligations

a) The warranty is limited to repairing and substitution, FOB Elcon Instruments factory, of the useless parts, for aconfirmed defect of materials and/or workmanship, free of charge, and the remaining, shipping, dismounting andmounting expenses (operations that in any case must be done in accordance with the supplier), at the custo-mer’s charge. In no case Elcon Instruments will be held responsible for expenses, for loss of profit and/or dama-ge, direct or indirect, that can be incurred by the customer due to a fault or defect of the material.

b) The warranty ends for instruments or materials damaged by:- shipment- storage non conforming to the instruction manual specifications- incorrect installation- loss of adequate protection for the type of installation (mechanical, climatic, etc.)- incorrect application of power supply voltage- erroneous wiring of the power supply line (applied on input or output measuring circuits)

c) The warranty ends for instruments or materials if repaired, modified, or simply tampered with, even if only inpart, by personnel not authorised by Elcon Instruments and also ends if used in improper way and/or not confor-ming with the given instructions.

d) The warranty is valid only if payment has been received from the customer in a timely fashion, as per the origi-nal agreement; otherwise it is void.

e) All parts that are subject to normal wear and inevitable deterioration are excluded from this warranty.

f) In case of having to return the instrument to one of the Elcon Instruments authorised labs for repair, the custo-mer shall obtain a written authorisation with shipping instructions from Elcon Instruments.Shipment expenses, all the concerned burdens, and the risk of loss or damage of the returned instrument areexclusively born by the customer.

The same rules apply also when the instrument needs to be replaced.

g) During the warranty period, the customer will allow any personnel appointed by Elcon Instruments execute con-trol of the instruments and materials.

h) The customer cannot require cancellation of the contract in reason of vices or defects, but only their eliminationor, when they cannot be repaired, the replacement of the instruments, if available on the market. In case thereplacement is for any reason impossible, Elcon Instruments has the faculty to offer instruments of the same orequivalent type, quality and efficiency, suitable to the same use.

If the customer refuses such offer without justified motivation he is entitled to reimbursement of the moneyalready paid or a refund of the real incurred expenses.

i) For items sub-supplied by Elcon Instruments the standard warranty terms as given by the original manufacturerare applicable.

j) The warranty must be considered for material repaired, substituted on ex works basis.

Such warranty replaces and supersedes any other declared or implicit warranty

11. ACRONYMS

AMS Asset Management Solutions

DCS Distributed Control System

FSK Frequency Shift Keying

HART® Highway Addressable Remote Transducer

HHC Hard Held Communication

HIS Elcon HART Interface Solutions

HSM HART Signal Multiplexer

IAC Elcon patented Interface Adapter Card

IS Intrinsic Safety

MM Multiplexer Module

MW Maintenance Workstation

PCC Process Control Unit

PLC Programmable Logic Controller

SCADA Supervisory Control and Data Acquisition

SSMS Smart Signal Multiplexer System

ST Smart Transmitter

TB Termination Board

• Cornerstone is a trademark of Applied System Technologies, Inc.

• HART is a registered trademark of Rosemount Inc.

• Windows is a trademark of Microsoft Corporation.

• AMS Asset Management Solutions is a trademark of Fisher Rosemount.

- 24 -

IM-ENG-216/GB

- 25 -

12. APPENDIX A: MUX2700G ISOLATION STRUCTURE

12.1 Three-port isolation

The three-port isolation structure of the Mux2700G is depicted in Fig.8. As you can see, both the 24V supply inputand the RS-485 serial interface are isolated from the HART section, that is to say, from the HART signals on thefield devices. This is full galvanic isolation, implemented either by transformer or by optocoupler.

The galvanic isolation specifications for the Mux2700G are summarised in the following table:

Mux2700G GALVANIC ISOLATION SPECIFICATIONS

12.2 Input-channels isolation

When you look at the field channels, you can see that full galvanic isolation is not implemented. Instead, a series ofnon-polarised capacitors are inserted on each external interface line. The purpose of these capacitors is to blockthe DC signal component present on each 4-20mA external loop, avoiding both a DC error induced on the loopand any undesirable ground-loop.

The presence of a non-polarised capacitor in series with both the + and the – terminal of each channel is very con-venient for a variety of reasons, as summarised in the following:

• It is possible to sense the HART signal at different DC voltage levels on each channel, as often required whenthe same MUX interfaces both Transmitters and I/P devices or in other “mixed” configurations.

• It is not mandatory, to connected the + MUX terminal to the + side of the 4-20 mA current loop (in fact, the MUXinput terminals are basically not polarised).

IM-ENG-216/GB

POWER

SUPPLY

UNIT

+24V

RS-485

INTERFACE

OPTOISOL.

CPU

MUX

A

HARTMODEM

+

+

A1

A3

SCREEN

A4,A5,A6

A31A

A30B

A32

2.2µF

0.68µF

2.2µF

0.68µF C32

B32

C1

B1

CH1

CH32

FIG. 8Mux2700G ISOLATION STRUCTURE

24V supply Field channels 1400 Vac, rms

24V supply RS-485 serial port 1400 Vac, rms

RS-485 serial port Field channels 500 Vac, rms

- 26 -

• As better explained in section 12.4, the MUX can tolerate one or more short-failed input capacitors while stillworking properly, the probability of loop interference is also very low for a wide range of internal MUX faults.

The MUX input isolation was designed to allow the highest flexibility in connecting the channels to sense the HARTsignal. The max 30 Vdc input voltage (specified between all terminals, both belonging to the same channel or not)makes it possible to connect any MUX terminal to whatever voltage level can be derived from a 24 Vdc supply,+20% tolerance included.

The input-channels isolation specifications for the Mux2700G are summarised in the following table:

IM-ENG-216/GB

Channel number: 32 signal loops (64 terminals)

Channel isolation technique: capacitor isolation, 2 capacitors for each loop

+ terminal capacitor: 0.68 µF, 63V polyester capacitor (non-polarised)

- terminal capacitor: 2.2 µF, 50V non-polarised electrolytic capacitor

Allowed common mode voltage: up to 30V

Max input common-mode voltage: 30 Vdc(between terminals of different channels)

Max input differential-mode voltage: 30 Vdc(between terminals of the same channel)

Common mode internal clamping: +/- 10V (for transient or AC signals)(between terminals of different channels)

Differential mode internal clamping: +/- 5V (for transient or AC signals)(between terminals of the same channel)

Mux2700G INPUT ISOLATION SPECIFICATIONS

To avoid any possible damage to the sensitive input circuitry, an internal, zener-diode based clamping network(Fig. 9) was inserted that operates both on common-mode and on differential-mode transients. This is requiredbecause, for relevant input transient or AC signals, the input capacitors could momentarily couple to the input cir-cuitry with a voltage level higher than the allowed voltage rating (i.e., +/- 5V).

Typically, the clamping network needs only to operate at the MUX unit during plug-in time, when the input capaci-tors are initially charged. During the capacitors charge time (typically less than 1 ms) the input circuit does in factsink a some DC current from the loop, but the induced error on the 4-20 mA signal is so short in time that it is rarelydetected in any situation.

All diodesare 5V Zeners

A+

+CHx

+CHy

FIG. 9Mux2700G INPUT CLAMPING NETWORK

- 27 -

12.3 Galvanic versus capacitive isolation

Having understood the advantages of a full, non-polarised capacitor-based isolation, you must however be awarethat this is not the same as a full galvanic isolation implemented on each channel, which was avoided on the MUXdesign due to space constraints and higher manufacturing costs.

In the following, we will try to outline the main differences between the Galvanic and the Capacitive isolation techni-ques:

• Full, galvanic isolation is associated with clearly specified, solid isolation distances, with reference to the applica-ble standards. For space reasons, the selected Mux2700G capacitors are not generally compliant with this requi-rement.

• Full, galvanic isolation is generally requested to withstand a test voltage starting from 500 Vdc up, while the Mux2700G capacitor rating is around 60 Vdc only.

• Full, galvanic isolation is generally specified with the lowest possible stray capacitance. For functional reasons(that is to say, to enable the HART frequency acquisition) the Mux2700G capacitors are much higher of what isusually found in a galvanic isolated solution.

Due to the previous considerations, when you connect a MUX2700G to 4-20mA loops that are galvanic isolated fromeach other, you loose the full galvanic isolation among the channels. On the other hand , you still have a relevantadvantage with respect to a solution that simply connects the channels with a common point, because you stillhave full DC isolation up to the specified voltage and you don’t need to worry about possible ground-loop inducederrors on the 4-20mA signals.

12.4 Safety-related issues

It is important to stress the fact that capacitor-based isolation is not equivalent to a full galvanic isolation, howeverthis does not mean that the Mux2700G can be expected, under reasonable fault conditions, to interfere with theconnected 4-20 mA loops. A few application examples can in fact be useful to clarify the situation.

• Galvanic isolated field loops

Let us assume that you connect with 4-20mA loops that are fully galvanic isolated from each other. In this case,it can be shown that a single shorted input capacitor on each channel, plus any possible additional MUX fault(apart from shorted input capacitors) does never result in any interference on the 4-20mA loops. In addition, witha single shorted capacitor on each channel the MUX is still fully functional.

In a more formal term, the probability of any “electrical feedback” of the Mux2700G on the loops signals is verylow, and you can consider the control system for “fail-safe” applications (this doesn’t mean, however, that theMUX is fail-safe certified or that it will keep working properly when in a generic “single-fault” condition).

• Common-point field loops

A similar situation can be found when the 4-20mA loops which the Mux2700G connects to share a common Vdcconnection point, with a current sense resistor < 300 Ohm to GND (Fig. 10) .

As before, it can in fact be shown that a single shorted capacitor on each channel, plus any possible additionalMUX fault (apart from shorted input capacitors) does never result in any interference on the 4/20 mA loops. Inaddition, with a single shorted capacitor on each channel the MUX is still fully functional.

IM-ENG-216/GB

- 28 -

As a final remark, we can observe that, whatever is the field-loops isolation or connection, a single capacitor faultplus any other possible additional fault within the Mux2700G never results in any errors induced from the Mux2700Gon any 4-20mA loop.

12.5 Conclusions

By this note, it was possible to clarify how the Mux2700G isolation structure is such to guarantee both an high levelof application flexibility and a good reliability and fault tolerance (as for induced errors).

The presence of two series capacitors on each 4-20mA loop was discussed and the advantages of the solutionexplained.

Some safety related issues were finally discussed, showing that, with a minimum of application-related analysis,the Mux2700G can be designed so to minimise the probability of any electrical feedback on the connected 4-20mAloops.

IM-ENG-216/GB

A+

+CHx

+CHy

+ 24 Vdc

R < 300 Ohm

Tx

Tx

R

R

GND

FIG. 10COMMON-POINT FIELD LOOPS CONFIGURATION

triconex fta-mux cards - hptb/32/tr-ai-01

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