write message to trendview recorder via modbus

Write Message to Trendview recorder via Modbus

1Dan Weise, Lesman Instrument Co. © 2012 rev2a

Write Message to Trendview via Modbus

• A Modbus master can write text messages to a recorder – PLC, SCADA, HMI

• Messages appear– on the Trendcharts

– in the User Message log along with a date/time stamp

• Trendview recorder is a Modbus slave, no credits are needed.

• The messages can be written over either ethernet (Modbus TCP) or RS-485 (Modbus RTU).RS-485 (Modbus RTU).

• All recorders have 16 holding registers in the 4xxxx memory area reserved for messages of up to 32 ASCII characters

– starting address = 0004, register (4)0005

• Recorder configuration:– Slave mode must be enabled

– recorder must be assigned a slave node ID number, 1 – 247

– for Modbus RTU, the RS-485 port must be configured and the settings must

match the Master’s settings.

2Dan Weise, Lesman Instrument Co. © 2012

Trendview Setup

Trendview Setup for Modbus RTU over RS-485

does not matter, can be something else


Modscan 32 as Modbus MasterModscan 32 Connection setup:

USB/RS-485 adapter installed on PC’s COM 8

Direct Connection to COM8 matches the COM port shown in Device Manager


Modscan 32

Modscan 32 Connection setup:

Comm settings under Configuration match Trendview’s setup


Write Message to Trendview via Modbus

Compose message of ASCII character hex values

• Setup > Extended > Preset Regs


Modscan 32

Enter data

• Slave Device node number (1)

• Register address 5 = 40005, starting from 40001

• Number of registers (points)

Number of points should be 4,

not 3, for message “Cleared”


Modscan 32

For each register address, enter the hex values for two ASCII characters

sample message: Cleared

• 43 = C

• 6C = l

• 65 = e

• 61 = a

• 72 = r• 72 = r

• 65 = e

• 64 = d

• 00 = nul

• ‘To File’ saves the setup

• ‘From File’ loads a previously configured setup

• ‘Update’ sends message to slave device8Dan Weise, Lesman Instrument Co. © 2012

Modscan 32

Modscan32’s completed ‘write message’ transaction for

• Slave (Device) 1

• Address 40005

• 4 registers (8, 8 bit ASCII characters)


Trendview Mark-on-Chart

Message “Cleared” marked on the Trendview chart


ASCII Table


Banner USB/RS-485 converter cable

• Banner USB/RS-485 converter cable

• part number BWA-HW-006

• used for Trendview Modbus RTU

• FTDI chipset

– registered with Microsoft

– if installed on PC with internet access, will find drivers and self-access, will find drivers and self-

install

• Check Device manager to see which COM port the converter installs on


Wiring Banner USB-RS-485 converter cable toTrendview X series RS-485 Modbus

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• Use 5 pin M12 male cordset to adapt Banner M12 5 pin Female connector to flying leads

• Wire Honeywell connector as shown

Banner M12 node connections

Trendview

Banner M12 node connections

RS-485 uses white, black & gray

13Banner

Dan Weise, Lesman Instrument Co. © 2012

Trendview Manual: write message via Modbus

Input Text message

• This facility allows a text message to be passed to the recorder to be

annotated on the chart and added to the message log.

• The maximum length of the message is 32 bytes of ASCII characters, which

need not be null-terminated.

• It operates by utilising modbus function code 16 (0x10), Preset Multiple

registers, and the unique address 0x0004 in the Modbus global register map (Table A-1). The Modbus message format follows that shown in map (Table A-1). The Modbus message format follows that shown in

section 3.7 of the document cited.

• The Start Address will be 0004, and the Byte Count of the number of bytes

in the text message. (# of characters/2)

• As [a minimum of] 2 Modbus registers are needed to pass an address

[range] to [by] function 16, the Number of Addresses has to be back

calculated from the required Byte Count to give the lowest integer such that

(Number of Addresses) / 2 ��= Byte Count.

• For example if Byte Count = 4, then Number of Addresses = 2

• But if Byte Count = 5, Number of Addresses = 3.


Trendview Manual: write message via Modbus

Input Text message, con’t.

• As an example, to send the 5-character message Start to a slave address

02 the complete [10(hex) function code] message would be:

• The response follows the normal response for function code 16 given in

section 3.7, and so to the above message the response would be: – 02 10 00 04 00 03 CRC CRC


write message to trendview recorder via modbus

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