Help: Computing Checksum

[Van 0]

Equipment: CJ1M-CPU11 I am trying to figure out how accomplish this using ladder logic. The Omron instruction FCS(180) is similar to my needs but doesn't appear to perform the same math operation (I don't get the same result). I think I have to write this one. Question One: Best method to perform the math? Which instruction would you recommend? Question Two: What really stumps me is the conversion of each digit of the last byte into an ASCII code.

[BITS N BYTES 66]

In both your examples the Hex sum is incorrect. Should be "28D" and "28E". Use SUM[184] instruction to sum BYTES to calculate these values. In your example the first C[ontrol] word of the SUM instruction would be 13 bytes = #D. The second contol word [C+1] = #2000.

[Van 0]

Excellent! Thank you for your assistance! And I used ASC(086) to convert my resultant: ASC SUM_RES #0030 XMT_DATA_CS it worked! Edited 16 Jun 2008 by Van