Modbus Function Code Details; Reading/Holding Register Contents (03H); Write In Single Holding Register (06H) - YASKAWA P7 User Manual

Modbus Function Code Details

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Reading/Holding Register Contents (03H)

Read the contents of the storage register only for specified quantities. The addresses must be consecutive, starting from a
specified address. The data content of the storage register are separated into higher 8 bits and lower 8 bits.
The following table shows message examples when reading status signals, error details, data link status, and frequency
references from the slave 2 Drive.
Command Message
Slave Address
Function Code
Higher
Start
Address
Lower
Higher
Quantity
Lower
Higher
CRC-16
Lower
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Write In Single Holding Register (06H)

Command Message
Slave address
Function code
Register Upper
Address
Lower
Setting Upper
Data
Lower
Upper
CRC-16
Lower
Response Message
(During Normal Operation)
02H Slave Address
03H Function Code
00H Data quantity
20H
1st storage
register
00H
04H
Next storage
register
45H
F0H
Next storage
register
Next storage
register
CRC-16
Fig. D.6 Function Code 03H Message Example
Response Message
(During Normal Operation)
01H
Slave address
06H
Function code
00H
Register
01H
Address
00H
Setting
03H
Data
98H
CRC-16
0BH
Fig. D.7 Function Code 06H Message Example
Communications D - 7
02H
03H
08H
Higher 00H
Lower 65H
Higher 00H
Lower 00H
Higher 00H
Lower 00H
Higher 01H
Lower F4H
Higher AFH
Lower 82H
01H
06H
Upper 00H
Lower 01H
Upper 00H
Lower 03H
Upper 98H
Lower 0BH
Response Message
(During Error)
Slave Address 02H
Function Code 83H
Error code 03H
Higher F1H
CRC-16
Lower 31H
Response Message
(During Error)
Slave address
80H + Function Code
Error code
Upper
CRC-16
Lower
01H
86H
21H
82H
78H