My name is Steffen Pohle and I wrote the following two applications because i got curious about the modbus tcpip protocol. During my day job as an DCS maintenance technician I had to solve different modbus tcpip issues where sometimes debugging and monitoring tools are needed. During my private time i could write some testing and monitoring tools which i can put under the GPL licence so everyone can use these tools.

In private I am a linux user, so don't expect that testmodbus-server windows binarys is free of errors, i was happy to compile and run them with WINE.

ModbusClient is a simple tool to monitor/read cylcic values from any modbus-tcpip device and prints them out to the console. The output can be piped into a log file. It is my first attempt to create a .Net application from scratch. I could compile this CS-file with a Windows10 installation and the binary seem to run on any windows server as well, so it should work for anyone.

Y:\>
Y:\>modbusclient.exe -host localhost -port 502 -fc 1 -reg 0 -count 16 -fc 3 -reg 16 -count 10 -timeout 2
modbusclient.exe    [Version 1.1]
        URL: https://steffen.gulpe.de/modbus-tcpip
Host: localhost:502   UnitID: 0   Timeout: 2s
  FunctionCode: 1  Register: 0  Count: 16
  FunctionCode: 3  Register: 16  Count: 10
23.08.2021 23:06:47 TCPLen:11   FC:1 Reg:0      01000000        00000000
23.08.2021 23:06:47 TCPLen:29   FC:3 Reg:16     54153   17475   65496   783     0       0       0       0       0       0
23.08.2021 23:06:49 TCPLen:11   FC:1 Reg:0      01000001        00000000
23.08.2021 23:06:49 TCPLen:29   FC:3 Reg:16     21612   17484   65462   817     0       0       0       0       0       0
23.08.2021 23:06:51 TCPLen:11   FC:1 Reg:0      11000001        00000000
23.08.2021 23:06:51 TCPLen:29   FC:3 Reg:16     56525   17492   65441   851     0       0       0       0       0       0
23.08.2021 23:06:53 TCPLen:11   FC:1 Reg:0      10000000        00000000
23.08.2021 23:06:53 TCPLen:29   FC:3 Reg:16     34870   17501   65437   886     0       0       0       0       0       0
23.08.2021 23:06:55 TCPLen:11   FC:1 Reg:0      11000000        00000000
23.08.2021 23:06:55 TCPLen:29   FC:3 Reg:16     28714   17510   65453   921     0       0       0       0       0       0
^C
Y:\>

If you find any bugs please contact me at steffen@gulpe.de.

A tool for testing modbus clients, you can do basic simulation of registers and values. Kind of usefull tool if it comes to debug modbus-tcpip issues. Especially with different vendors. The programm was develouped for linux only, but i could manage to get a winodws binary. All you need is included in the source package. The server is simple to use, start the application connect your PLC or DCS system to it and do your testings.

You will be able to set different registers, check which register was requested for reading and writing and you can simulate some values.

If you find any bugs please contact me at steffen@gulpe.de.

The tool to thest some modbus servers with. The linux verison is running fine. On the windows part there are still alot of issues. Please be carefull using this tool. Currently only reading is allowed.

Downloads

• Windows Build TestModbus-Client-0.1.9-win.zip

Browse the Source Git Repository.