Hi,
I am using MODBUS RTU.
I get the correct sequence data from my system.
but in modbus poll show the crc error.
Please help me. I am new be for modbus.

Thanks in advance.

 

Add as many parenthesis to your code as you can. Many small C compilers have subtle ordering dependencies which mean a published Modbus CRC16 routine might nOT always work for you - for example sign-extension might cause shifting to be 'wrong', etc.

If you are NOT using C & are using a java/Python/Ruby (which likely do NOT have unsigned variable), then you must be carefully to keep masking off the data & use over-sized variables.

 

Hi, Thanks for your reply,
I check in "simply modbus" data sequence and crc all things are correct.
is any changes for mosbus poll, Qmodbus or modscan 32.

after that I just send data from one PC to other according to sequence with crc. but there is no any program in this test.

So can you suggest me what happen..

Thanks for your kind support....

 

Thanks Lynn, I got the solution.
Its my mistake to understand some thing in modbus protocol.

Thanks one again...