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Case 369

Thread #953 | 2020-09-22 08:24 UTC | James | replies: 0
Post #1 | 2020-09-22 08:24 UTC | James
Question:
The RMS-HCD Modbus RTU communication is not clear. It explains the ordering of the bytes for the Checksum (LSB, MSB in the CRC).

Possible Root Cause:
  1. No example of the order of the bytes for the Checksum.
Solution:
Hex format: 01 04 00 00 00 04 f1 c9
  1. 01 device address
  2. 04 command id
  3. 00 not used
  4. 00 start address, init16
  5. 00 not used
  6. 04 number of data = 4, init 16
  7. f1 > CRC 16bit Modbus (LSB)
  8. c9 > CRC 16 bit Modbus (MSB)
Additional Information:
The PCD includes this example with the LSB, MSB in the CRC. It explains the ordering of the bytes for the Checksum.
https://service.rotronic.com/manual/modbus2.html.

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