Author Topic: MODBUS RTU mapping  (Read 12369 times)

vijay

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MODBUS RTU mapping
« on: April 19, 2004, 07:34:44 PM »
I am trying to interface to a Aromat GT-01 touchpanel. This supports MODBUS RTU so the interface should be simple. However the MODBUS mapping makes no sense:

INPUT 100000 to 165520
COILS 000000 to 065520
REGS  400000 to 499999


How does this map to the TD PLC ?

Any help appreciated - Vijay ?

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Re:MODBUS RTU mapping
« Reply #1 on: April 20, 2004, 11:37:09 AM »
There is an updated T100MD+ modbus mapping document that you can download from the following link:

http://www.tri-plc.com/appnotes/modbus-map.pdf

This document provide the mapping of the bit I/Os to the MODBUS bit addresses. However, we treat the MODBUS bit address as from 0 to 2048 range only and we treat all I/O bits the same regardless of whether it is an input, an output, relay, timer or counter bit. Inputs are mapped to bit address 1 to 256. Outputs are mapped to bit addresses 257 to 512, etc.  

It seems like the GT-01 panel uses the first digit to represent the I/O type, yet it uses zero offset to represent the bit which is not quite MODBUS like. Anyway,  please try the following:

   Input  1:  100000
   Input  2:  100001
   .....
   Input 96: 100095

   Output 1:  000256
   Output 2:  000257
     ....
   Output 96: 000352

Etc.

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