YASKAWA JOHB-SMP3-MA Technical Manual page 30

7 Modbus TCP/IP Messaging
Description
Slave Address (Unit Identifier)
Function Code
Number of Data Bytes
Register Values
*1 N = Quantity of Registers
Description
Slave Address (Unit Identifier)
Error Code
Exception Code
Examples of Fault Response, Read Response, and Read Multiple Registers Command
Table 7.9 lists command examples to 4 read register contents (register addresses 0020 (Hex.) to 0023 (Hex.)) from
a drive with the slave address (unit identifier) 02 (Hex.).
Table 7.10 shows examples of responses indicating that multiple registers have been read successfully. The
contents read from 0020 (Hex.) are 1770 (Hex.), 1770 (Hex.), 0109 (Hex.), and 0000 (Hex.).
Table 7.11 shows examples of an error response when reading multiple registers. The exception code is 02 (Hex.)
(indicating a register number error).
Starting Register
Quantity of Registers
*1 This option is set up to use PLC based (holding) register addressing (base 1). The drive will automatically convert the register
address to one more than the address sent over the network before it will respond.
When reading the starting register 0020 (Hex.) from the PLC:
1. The PLC sends out a command specifying the starting register 001F (Hex.) to the network.
2. The drive automatically convert the starting register 001F (Hex.) to 0020 (Hex.).
3. The drive responds the value of register address 0020 (Hex.) to the PLC.
Starting Register
Next Register
Next Register
Last Register
30
Table 7.7 Read Multiple Registers (Response)
Table 7.8 Read Multiple Registers (Error Response)
Table 7.9 Example Read Multiple Registers Command
Description
Slave Address (Unit Identifier)
Function Code
*1
Table 7.10 Example Read Multiple Registers Response
Description
Slave Address (Unit Identifier)
Function Code
Number of Data Bytes
Byte No.
1
1
1
*1
N × 2
Byte No.
1
1
1
Upper
Lower
Upper
Lower
Upper
Lower
Upper
Lower
Upper
Lower
Upper
Lower
YASKAWA SIEP C730600 0IB Modbus TCP/IP Technical Manual
Data (Hex.)
00 - FF
03
*1
2 × N
Values contained in slave registers
Data (Hex.)
00 - FF
83
Refer to Modbus TCP/IP Exception Codes.
Data (Hex.)
02
03
00
20
00
04
Data (Hex.)
02
03
08
17
70
17
70
01
09
00
00