Yaskawa Z1000U HVAC Matrix Bypass User Manual

Page 391

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The example in

Table D.2

shows the CRC-16 calculation of the slave address 02H and the function code 03H, yielding the

result D140H.

Note:

This example does not show the calculation for a complete MEMOBUS/Modbus command. Normally data would follow in the calculation.

Table D.2 CRC-16 Checksum Calculation Example

Description

Calculation

Overflow

Description

Calculation

Overflow

Initial Value (FFFFH)

1111 1111 1111 1111

Function Code 03H

0000 0000 0000 0011

Address 02H

0000 0000 0000 0010

XOR w result

1000 0001 0011 1101

XOR w initial value

1111 1111 1111 1101

Shift 1

0100 0000 1001 1110

1

Shift 1

0111 1111 1111 1110

1

XOR w A001H

1010 0000 0000 0001

XOR w A001H

1010 0000 0000 0001

XOR result

1110 0000 1001 1111

XOR result

1101 1111 1111 1111

Shift 2

0111 0000 0100 1111

1

Shift 2

0110 1111 1111 1111

1

XOR w A001H

1010 0000 0000 0001

XOR w A001H

1010 0000 0000 0001

XOR result

1101 0000 0100 1110

XOR result

1100 1111 1111 1110

Shift 3

0110 1000 0010 0111

0

Shift 3

0110 0111 1111 1111

0

Shift 4

0011 0100 0001 0011

1

Shift 4

0011 0011 1111 1111

1

XOR w A001H

1010 0000 0000 0001

XOR w A001H

1010 0000 0000 0001

XOR result

1001 0100 0001 0010

XOR result

1001 0011 1111 1110

Shift 5

0100 1010 0000 1001

0

Shift 5

0100 1001 1111 1111

0

Shift 6

0010 0101 0000 0100

1

Shift 6

0010 0100 1111 1111

1

XOR w A001H

1010 0000 0000 0001

XOR w A001H

1010 0000 0000 0001

XOR result

1000 0101 0000 0101

XOR result

1000 0100 1111 1110

Shift 7

0100 0010 1000 0010

1

Shift 7

0100 0010 0111 1111

0

XOR w A001H

1010 0000 0000 0001

Shift 8

0010 0001 0011 1111

1

XOR result

1110 0010 1000 0011

XOR w A001H

1010 0000 0000 0001

Shift 8

0111 0001 0100 0001

1

XOR result

1000 0001 0011 1110

XOR w A001H

1010 0000 0000 0001

Perform operations with next data (function code)

XOR result

1101 0001 0100 0000

CRC-16

1101 0001 0100 0000

D 1 4 0

(Lower) (Upper)

Continue from here with next data.

n

Response Data

Perform a CRC-16 calculation on the response message data as described above as a validation check. The result should match

the CRC-16 checksum received within the response message.

D.7 Message Format

YASKAWA SIEP YAIZ1D 01A Z1000U HVAC MATRIX Drive Bypass Technical Manual

391

D

MEMOBUS/Modbus Communications

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