10.6 MEMOBUS/Modbus Communications
744 YASKAWA SIEPYAIH6B01A HV600 AC Drive Bypass Technical Reference
Description Calculation Overflow Description Calculation Overflow
XOR w A001 (Hex.) 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 A001 (Hex.) 1010 0000 0000 0001 -
Shift 8 0010 0001 0011 1111 1 XOR result 1110 0010 1000 0011 -
XOR w A001 (Hex.) 1010 0000 0000 0001 - Shift 8 0111 0001 0100 0001 1
XOR result 1000 0001 0011 1110 - XOR w A001 (Hex.) 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.
Response Data
The drive does the CRC-16 calculation for the response message and makes sure that the data does not have errors.
Make sure that the calculated value is the same value as the CRC-16 in the response message.
â—† Examples of Messages for Commands/Responses
The items in this section are examples of messages for commands/responses.
â– Read Multiple Holding Registers
Uses function code 03 (Hex.) to read the contents of a maximum of 16 holding registers.
Table 10.23 shows example messages when the drive reads status signal from the drive of slave 2, the error contents,
fault contents, and frequency references.
Table 10.23 Message Example When Reading the Contents of Holding Register
Byte Command Message
Setting Data
(Hex.)
Response Message (Normal)
Setting Data
(Hex.)
Response Message (Fault)
Setting Data
(Hex.)
0 Slave address 02 Slave address 02 Slave address 02
1 Function code 03 Function code 03 Function code 83
2
Starting No.
Upper 00 Data Qty 08 Error code 03
3 Lower 20
First storage
register
Upper 00
CRC-16
Upper F1
4
Data Qty
Upper 00 Lower 65 Lower 31
5 Lower 04
Next storage
register
Upper 00 -
6
CRC-16
Upper 45 Lower 00 -
7 Lower F0
Next storage
register
Upper 00 -
8 - Lower 00 -
9 -
Next storage
register
Upper 01 -
10 - Lower F4 -
11 -
CRC-16
Upper AF -
12 - Lower 82 -
â– Loopback Test
The loopback test uses function code 08 (Hex.) and returns the command message as a response message. This test
checks communication between the master and slave. The test code and data can use desired values.
Table 10.24 shows examples of messages given out when the loopback test is done with the drive of slave 1.
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