I have a Master-Slave Exchanging following Request Response. Can some one be kind enough to shed some light on this?

MASTER:
Request Bytes:

01 52 44 02 39 38 39 03 39 45 42 32 04

Request ASCII version: .RD.989.9EB2.

SLAVE:
Response Bytes:

01 39 38 39 02 32 2E 33 31 30 31 30 30 03 46 36 36 38 04

Response ASCII version:
.989.2.310100.F6.68.

I do understand that slave is 01 and slave saying my version is 2.3101 etc... I don't understand the function code and ASCII or RTU, LRC/CRC stuff.

I appreciate the help.

Thanks,
H

 

I think I have clue now. Register 989 is being read. Now I don't understand what '9EB2' is in the REQUEST. Is it the LRC/CRC? If yes, How is it generated? What are its inputs? Just the register alone/includes 'RD'/includes other hex values in between too?

Any help is appreciated.
Thanks,
H

 

Your question isn't very clear. Are you trying to compare Modbus/RTU messages to Modbus/ASCII messages (two different forms of Modbus)? If so, are the two messages suppose to be the same?

If they are suppose to be the same, it doesn't look right. The periods shouldn't be in the middle, there should be more characters. What are you using to view this with?