Chino KR2S, Инструкция по эксплуатации

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INST.No.INE-863B KR2S
【
Communication Interface
】
Instruction Manual
-26-
7-3-5
Error check
The error check of transmission frame differs depending on the mode.
RTU mode: CRC-16
ASCII mode: LRC
1. Calculation of CRC-16
The CRC method divides the information to be sent by a generating polynomial and transmits it by
attaching the calculated remainder to its end. The generating polynomial is as follows.
1 + X
2
+ X
15
+ X
16
The following calculation is performed for information from a slave address to the end of data.
1) Initialization (=FFFFH) of data of CRC-16 (consider as X)
2) Exclusive OR of data 1 and X (EX-OR)
→
X
3) 1-bit shifting of X to the right
→
X
4) For a carry existed, A001H and EX-OR are taken, else go to 5).
→
X
5) 3) and 4) are repeated up to 8-time shifts.
6) EX-OR of the following data and X
→
X
7) Same as 3) - 5)
8) Repeating up to the last data.
9) A message is created in the order from lower digits to higher digits of the calculated 16-bit data
(X).
Example)
When data is [02H][07H], the CRC-16 becomes 1241H.
Then the error check data becomes [41H][12H].