hot standby wireless link for railway signalling … · for instance, when a bell plunger of the...

Scheme of Block Operation with 2.4 GHz Digital Microwave RadioThe Block Instrument is connected to the fail-safe multiplexer - UFSBI using signalling or PIJF cable, so

that DC and FM signals are exchanged between them reliably. The UFSBI is subsequently connected to thecommunication media, i.e. Microwave Radio directly through RS232C data port DB9 connector (@ 2.4 Kbps)

For instance, when a bell plunger of the SGE DLBI or Diodo TLBI is pressed the DC signal generated fromthe Block Instrument, is used to energize an input relay at one end, which is transmitted to the other end throughthe communication media via modem to the other end, and subsequently picks up an output relay. The outputrelay is used to commutate the local DC supply to the receiving end Block Instrument, as if it is connected to theother machine using copper cable and thereby completes the DC current loop.

In order to perform the inter-station voice communication the Radio provides an Ethernet port. A VOIPadaptor is used to interface between the conventional E&M phones used in railways and the IP port of radio,thus providing toll quality secured voice communication.

Fig 1. System Layout of Block Working on Microwave Radio using UFSBI (as per RDSO/SPN/147/2005) including secured Voice Communication

HOT STANDBY WIRELESS LINK FOR RAILWAY SIGNALLINGUFSBI, AXLE COUNTER & SECURE VOICE

Shri I N Mukherjee, Director, Deltron Eqpt and Systems Pvt. Ltd.

Gyandeep - Anniversary Issue ‘16

Schemes of Digital Axle Counter (SSDAC / HA-SSDAC) Operation with 2.4 GHz band Secure DigitalRadioSingle Section Single Line Digital Axle Counter (SSDAC) Operation on Radio Link

The Radio and DAC-RS232 are kept in Station premises. The Digital Axle Counter is connected to theDAC-RS232 through Quad Cable. The DAC-RS232 is subsequently connected to the communication media,i.e. Radio, directly through RS232C data port DB9 connector.

Fig 3 . System Layout of SSDAC Working on Digital Radios

Single Section Single Line Digital Axle Counter (SSDAC) Operation on Radio Link & Quad Cable withAutomatic Media Switchover facility

In case Quad cable interface is available in this section, the DAC-RS232 can be connected to Quad cable aswell and the system will have two communication links – Quad Cable and Radio with Automatic MediaChangeover facility. If one communication media fails, the Media Changeover unit will automatically switchover to the other media. Hence, Communication Redundancy can also be achieved.

Fig. 4 : System Layout of SSDAC Working on Radio & Quad Cable with Automatic Media Switchover


Single Section Digital Axle Counter (SSDAC) Operation on Double Line over Radio LinkThe Radio has two RS 232 serial communication port for necessary interfacing with Axle counter. Availability

of inbuilt multiple RS 232 serial interfaces make this radio system suitable for double line Axle Counterapplication.

In this application, two DAC-RS232 is required at each station end. Each one is connected with an Axlecounter through quad cable. Both the DAC-RS232 are connected with the Radio through RS 232 Interface.

Fig. 5 : System Layout of SSDAC on Double Line Working over Radio

Single Section Double Line Digital Axle Counter Operation on Radio Link & Quad Cable with AutoSwitchover

In case Quad Cables are available in this section, communication redundancy can be achieved in DoubleLine as well. In this application, Four DAC-RS232 is required at each station end. Two of them are connectedwith two track side Axle counters through quad cable. These two DAC-RS232 are connected with the Radiothrough RS 232 Interface. The other Two DAC-RS232 are connected to two quad cables. The RS 232 interfaceof these two DAC-RS232 and RS 232 Data output of the Radio are connevted to the Automatic MediaChangeover Facility.

If one communication media fails, the Media Changeover unit will automatically switch over to the othermedia. Hence, Communication Redundancy can also be achieved in single section double Line environment.


Fig. 6 : System Layout of SSDAC Working on Double Line section over Radio & Quad Cable withAutomatic media changeover.

Schemes of Block Proving with Digital Axle Counter with UFSBI & Block Panel (as per IRS:S-105/2012)over Radio Link

The arrangements of radio system are same as described for Single line and Double line axle counter operation.Additionally a UFSBI and a Block Panel is required at each station end.

A Block telephone is also provided for voice communication during block operation. This block phone isconnected to the VoIP interface of the radio system.

Figure 7 and Figure 8 show the schematic diagrams for the working of the system in Single & Double Line.

Technical Details of 2.4 GHz Digital Microwave Radio UsedThe Wireless Ethernet Bridge / Serial Gateway is powered by a reliable high-speed 2.4 GHz FHSS Radio. It

provides robust and secure wireless communication of simultaneous serial data and IP/ Ethernet packets toextend serial data and IP networks.

F e a t u r e s:• Standard 345 Kbps /1.1 Mbps wireless link rate• Long range, high speed communications with excellent receiver sensitivity and robust frequency hop-

ping• Two serial ports: RS232 and RS232/485/422• Supports Point-to-Point, Point-to-Multipoint, Repeater, Peer-to-Peer• Adjustable transmit power (100mW - 1W)• Radius Server Authentication• Full VLAN Support• Bringing industrial data into IP/Ethernet networks• User interface through local console, telnet, and web browser• Network management capability with SNMP V1, V2, V3• Local and remote firmware upgrading through FTP


Fig 7: Block Proving with Axle Counter with UFSBI & Block Panel (as per IRS:S-105/2012) for SingleLine on Radio Link

Fig 8: Single Section Double line Block Proving through Digital Axle Counter with UFSBI & BlockPanel on Radio Link


Fig.9a. Tower (30m) at Rangiya at N.F. Railway

Fig.9b. UFSBI at Rangiya at N.F. Railway with 2.4 GHz Radio & VOIP adaptor inside

Fig.3c. 24 dBi Grid Parabolic Antenna mounted on 30m Tower in Rangiya at N.F. Railway

Fig.9e Neals Ball Token Instrument working on Radio in Rangiya at N.F. Railway

Fig.9d. 2.4 GHz Microwave Radio and VOIP adaptor placed under physical Lock & Key inside UFSBI cabinet in Rangiya at N.F. Railway


Technical Details of VOIP adaptor

Technical Details of RS232 INTERFACE For Digital Axle CounterWith Railways modernizing its communication network, a need for working the Digital Axle Counters

using communication media other than quad cables was being felt.

Central Electronics Ltd. (CEL) has developed a product named DAC-RS232 to fulfill this need by allowingrailways to use any RS232 compatible device for the communication between CEL make Digital Axle Counter.

It allows Railways to migrate the axle counter communication (mostly for BPAC application) from quadcable to other media like Radio Channel or Optical Fiber or for enhancing the quality of this communication.CEL’s DAC-RS232 has been designed to work with CEL’s SSDAC (DACF-710P), HASSDAC (DACF-720P)and MSDAC (DACF-730) and uses all the safety factors required to work a safe axle counting system. It hasinbuilt addressing scheme so that a DAC-RS232 will communicate with its mated pair only. This reduces therisk posed by wrong configuration.

• DAC-RS232 ensures safety of axle counting system against misconfiguration through an inbuilt ad-dressing mechanism that allows only the mated DAC-RS232 units in a pair to communicate with eachother.

• Use of Radio interface with DAC-RS232, mitigates the issues associated with wired communication inchallenging geographical areas.

Specifications:

Features

Excellent Voice quality

Capable of handling DTMF

Web based configuration

LED/LCD Based front panel indicators

Power

Operating Voltage 12Vdc (11.5V to 13.8Vdc)

Voice Port

Number of channels 1

Four wire, isolated

Input Impedance 600 ohms typical

Output Impedance 600 ohms typical

Input Levels Adjustable

Output Levels Adjustable

Frequency Response 300 to 3300 Hz (within 1 dB)

Interface 10 BASE-T or 100 BASE-TX Ethernet with auto detect

Protocol Multicast RTP/ SIP

Vocoders Minimum G.711

FSK WAGO Connector, ITU-T V.21, 300 bps, Full Duplex

RS232 DB-9 Connector (Tx, Rx & GND), DCE

Input Power +24VDC

Consumption <5W

Dimension (L*W*H) 138mm*118mm*45mm

Casing Polycarbonate

hot standby wireless link for railway signalling … · for instance, when a bell plunger of the...

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