KS40 Modbus Controller

[Rafal Walczak]

Hello everyone
Im trying to communicate with KS40 controller (made by PMA) using my PC--->RS232--->ADAM 232/485 converter--->RS485--->KS40
I have a small program for modbus and sending Modbus frames to KS40 but no response. I lost all day to figureout what's going on but no success except one time when 2 minutes I had responses. I didn't know why.
Any ideas?
Greatings Rafal

 

[danw]

Is your PC program the Modbus master and the KS40 the Modbus slave?

A PC serial port gets dedicated to the program that calls it. Presumably your PC program doesn't go to sleep and release the serial port.

If you got a comm connection to work at all (2 minutes worth), then the basic comm settings, baud rate, word size, parity are correct and the A & B connection for the RS-485 link is correct.

Which leaves the PC program interacting with the KS40.

Assuming the KS40 is the Modbus slave, I'd try to talk to it using a Modbus master utility PC program like Simply Modbus or Modscan32, using the 232/485 converter to confirm the performance of the KS40. If the KS40 checks out that way, then something is going on in your PC program.

 

[Rafal Walczak]

Thanks for help danw
I use similar program to Modscan32. To be sure I installed Modscan32 but the same situation. KS40 is slave. All I got is timeout. Battle continue.

 

[Rafal Walczak]

Problem solved. If you have KS40 controller and you are plugged with RJ45 cable (for example to load configuration using BlueControl) then modbus interface doesn't work. This is stupid but its real.

 

[danw]

Glad you got it running. Thanks for the update.