checksum crc siemens s7-200
Onebit,
Thanks for your offer.
Yes, I still need some help (info).
Namely, the code following the destination and source bytes, the meaning of 6C in some telegrams and 7C in others.
Also, the code for the type of PLC memory being addressed ( eg 01 84) for V type memory and so on.
I guess what I am asking for are the definitions of bytes sent to and received from the PLC, and also the '10 02 00 5C 5E 16' type of messages both sent or received.
Also, what is the reply from the PLC when there is a checksum error.
We normally see an E5 when the message is received correctly, but when there is and error, there appears to be a '10 DST SRC xx CS 16 message returned form the PLC. (DST-destination, SRC - source, CS - Checksum)
Thanks for any assistance you may give me.
Andy