modscan32

M

Thread Starter

myself

Hi All,

I am developing a software to communicate with a controller which supports modbus. As a preliminary step to test the communication I tried using modscan32 (32 bit). Though I am able to read the values from the holding registers and input registers, i am not able to write into them. When i try to write, i get a message box saying "response ok". But the written value doesn't get reflected in the controller's display panel and modscan32 shows the previous value.

If the same operation is tried using modscan (16bit) the write operation succeeds and the value is also reflected on the display panel.

what is wrong? is there a difference in the way write queries are formed and executed?

Any clarification would be greatly appreciated

Thanks in advance-
Subbu
 
Hello,

You didn't explain what values you are trying to write.

The Modscan32 can force function 15/16 for write operations. Maybe your device does not support these functions. Try other software for ex. Modbus Tester from www.modbus.pl

Regards
Andrzej
 
Hi Andrej,

Thanks for the reply.
The device does support command 16.

The problem with the device was that I had to write 3 registers at a time (for that particular register address). That is how the device's internal logic is written. If i try to write a single register it fails.

Once again thanks for the reply.
 
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