YASKAWA HV600 Technical Reference page 743

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Communications Data
Communications data is a series of data that uses the combination of the communications register number and the data
for these registers. The data length changes when the description of the command changes. For a loopback test, it
switches to test code.
The communications register for the drive has a 2-byte length. Data that is written to the register for the drive is
usually 2 bytes. Register data that is read from the drive is also 2 bytes.
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Error Check
Error check uses the CRC-16 method to detect transmission errors. Use the procedure in this section to calculate
CRC-16.
Command Data
When the drive receives data, it will make sure that there are no errors in the data. The drive uses the procedure below
to calculate CRC-16, then the drive compares that data with the CRC-16 value in the message. If the CRC-16 values
do not agree, the drive will not execute a command message.
When you calculate CRC-16 in MEMOBUS/Modbus communications, make sure that you set the start value as FFFF
(Hex.). All 16 bits must be 1.
Use this procedure to calculate CRC-16:
1. Make sure that the start value is FFFF (Hex.).
2. Calculate the FFFF (Hex.) start value and the XOR of the slave address (exclusive OR).
3. Move the step 2 results one column to the right. Do this shift until the carry bit is 1.
4. When the carry bit is 1, calculate XOR via the result from the above step 3 and A001 (Hex.).
5. Do steps 3 and 4 until the 8th shift to the right.
6. Use the result of step 5 to calculate the XOR and the data of the following messages (function code, register
address, data). Do steps 3 to 5 until the last data, then calculate.
7. The result of the last right shift or the value of the last XOR calculation is the result for CRC-16.
Table 10.22 lists examples of the CRC-16 calculation of slave address 02 (Hex.) and function code 03 (Hex.). The
calculated results of CRC-16 for this section is D140 (Hex.).
Note:
The calculation example only gives information about some error checks with CRC-16. The drive will do the same error checks for the next
data.
Description
Initial value (FFFF (Hex.))
Address 02 (Hex.)
XOR w initial value
Shift 1
XOR w A001 (Hex.)
XOR result
Shift 2
XOR w A001 (Hex.)
XOR result
Shift 3
Shift 4
XOR w A001 (Hex.)
XOR result
Shift 5
Shift 6
YASKAWA SIEPYAIH6B01A HV600 AC Drive Bypass Technical Reference
Table 10.22 CRC-16 Calculation Example
Calculation Overflow
1111 1111 1111 1111 -
0000 0010 -
1111 1111 1111 1101
0111 1111 1111 1110 1
1010 0000 0000 0001 -
1101 1111 1111 1111 -
0110 1111 1111 1111 1
1010 0000 0000 0001 -
1100 1111 1111 1110 -
0110 0111 1111 1111 0
0011 0011 1111 1111 1
1010 0000 0000 0001 -
1001 0011 1111 1110 -
0100 1001 1111 1111 0
0010 0100 1111 1111 1
10.6 MEMOBUS/Modbus Communications
Description
Function code 03 (Hex.)
XOR w result
Shift 1
XOR w A001 (Hex.)
XOR result
Shift 2
XOR w A001 (Hex.)
XOR result
Shift 3
Shift 4
XOR w A001 (Hex.)
XOR result
Shift 5
Shift 6
XOR w A001 (Hex.)
Calculation Overflow
0000 0011 -
1000 0001 0011 1101 -
0100 0000 1001 1110 1
1010 0000 0000 0001 -
1110 0000 1001 1111 -
0111 0000 0100 1111 1
1010 0000 0000 0001 -
1101 0000 0100 1110 -
0110 1000 0010 0111 0
0011 0100 0001 0011 1
1010 0000 0000 0001 -
1001 0100 0001 0010 -
0100 1010 0000 1001 0
0010 0101 0000 0100 1
1010 0000 0000 0001 -
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