Are there any modbus experts out there that can help me? I am trying to read some discrete inputs on a scada device. Here is a successful command with modpoll.exe
C:\WINDOWS\system32>modpoll.exe -0 -m tcp -t 1 -r 101 -c 8 -1 192.168.1.63 modpoll 3.10 - FieldTalk(tm) Modbus(R) Master Simulator Copyright (c) 2002-2021 proconX Pty Ltd Visit https://www.modbusdriver.com for Modbus libraries and tools. Protocol configuration: MODBUS/TCP, FC2 Slave configuration...: address = 1, start reference = 101 (PDU), count = 8 Communication.........: 192.168.1.63, port 502, t/o 1.00 s, poll rate 1000 ms Data type.............: discrete input -- Polling slave... [101]: 1 [102]: 0 [103]: 0 [104]: 0 [105]: 1 [106]: 0 [107]: 0 [108]: 0
I am using the following related CR1000 program statements to accomplish what is posted above:
Public FSModBusPort As Long
Public FSReadResult As Long
Public FlexScadaSW(8) As Boolean
FSModBusPort = TCPOpen("192.168.1.63",502,1,500)
ModbusMaster(FSReadResult,FSModBusPort,9600,1,02,FlexScadaSW,101,8,3,1000)
TCPClose(FSModBusPort)
The FSReadResult is assigned -02 Illegal data address with different values of the Start argument (I have tried 0,1,100,101). Any suggestions?
Fixed, off by one. Used starting register 102.