Eaton ELC-PB, Programming Manual

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3 . I n s t r u c t i o n S e t
M N 0 5 0 0 3 0 0 3 E F o r m o r e i n f o r m a t i o n v i s i t : w w w. e a t o n . c o m
3 - 2 9 3
API Mnemonic Operands Function
108 CRC P S, n, D CRC Generator
Bit Devices Word devices Program Steps
Type
OP
X Y M S K H KnX KnY KnM KnS T C D E F
S *
n * * *
D *
CRC, CRCP: 7 steps
ELC ELCB ELCM
PB PC/PA/PH PV PB PH/PA
32 16 P 32 16 P 32 16 P 32 16 P 32 16 P
Operands:
S : Starting address for the checksum operation (RTU mode) n : Number of values to perform the
operation on ( n =K1~K256) D : Destination for storing the operation result
Description:
1. If n is out of range, an error will occurred and the instruction will not be executed. If an error
occurs, M1067 and M1068 = ON and error code H’0E1A will be recorded in D1067.
2. 8-bit conversion mode: When M1161 = ON, divide the hexadecimal data that starts with
source S into the high byte (invalid data) and low byte and have the CRC operation performed
on n values and store the result in the low byte of D (upper 8-bit of D will be zero)
3. 16-bit conversion mode: W hen M1161 = OFF, divide hexadecimal data that starts with source
S into the high byte and low byte and have the CRC operation performed on n values and
store the result in the low byte and high byte of D
Program Example:
RTU communication mode: Data stored as following:
Register Data Descriptions
D100 low byte 01 H Address
D101 low byte 06 H Function
D102 low byte 07 H
D103 low byte 06 H
Data address
D104 low byte 17 H
D105 low byte 70 H
Data content
D106 low byte 66 H CRC CHK 0
D107 low byte AB H CRC CHK 1
The CRC CHK (0,1) above is the error check code and it can be calculated using the CRC
instruction (8-bit Mode, M1161= ON).
M1000
CRC D100 K6 D106
CRC check: 66 H is stored in the lower 8-bits of D106 and AB H is stored in the lower 8-bits of D107.