Reverse Engineering Checksum (RS485 Bus)

Question

I have the following data. Can someone help me reverse engineer the checksum calculation?

Data                            Checksum
01 02 80 05 00 00 00 00 00       7d 8c
01 03 80 05 00 00 00 00 00       ae cb
01 04 80 05 00 00 00 00 00       b6 0c
01 05 80 05 00 00 00 00 00       65 4b
01 06 80 05 00 00 00 00 00       10 83
01 07 80 05 00 00 00 00 00       c3 c4
01 08 80 05 00 00 00 00 00       01 1d

This answer should help you. RS-485 Checksum Reverse Engineering (Watlow EZ-Zone PM) — fpmurphy, Jun 24 '18 at 11:15
@fpmurphy1 Thanks for your answer. I have tried out the checksum calc from this thread, but it doesn't match. I think this is another calculation. My bus is an internal bus from a german paul novus300 air condition. Have you another idea? — Schack, Jun 24 '18 at 21:00

score 2 · Accepted Answer · answered Jun 25 '18 at 17:31

2

Google is your friend. A search for "crc calculation online" delivered the solution on the top hit:

CRC Calculator (Javascript)

answered Jun 25 '18 at 17:31

josh

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You are very welcome! Sometimes the most obvious solutions are the hardest to find! – josh Jun 27 '18 at 13:49
I have test it now --> It works for me. Now I have a function in python to calculate it. Great. – Schack Jun 27 '18 at 18:13

Reverse Engineering Checksum (RS485 Bus)

1 Answers1