User`s manual

84
FX3U Series Programmable Controllers
User’s Manual - MODBUS Serial Communication Edition
9 Slave Specification
9.1 MODBUS Slave Command Code List
9. Slave Specification
This chapter explains the configuration of the slave for MODBUS Serial Communication.
9.1 MODBUS Slave Command Code List
Command Code
Subcommand
Code
Command Name Details
0x01 Read Coils Read binary (R/W) devices
0x02 Read Discrete Inputs Read binary (RO) devices
0x03 Read Holding Registers Read 16 bit (R/W) register
0x04 Read Input Registers Read 16 bit (RO) register
0x05 Write Single Coil Write single binary device
0x06 Write Single Register Write single 16 bit register device
0x07 Read Exception Status
Read 1 byte of vendor specified data
CH1: M8060 - M8067
CH2: M8060 - M8062, M8438,
M8064 - M8067
0x08
Diagnosis
0x00 Return Query Data Loop back function
0x01
Restart Communication
Option
Restart communication
- Clear all counters
- Recover from listen only mode
- Reset event log (if requested)
0x02 Return Diagnostic Register
Read 16 bit register of vendor specified data
CH1: M8060 - M8067
CH2: M8060 - M8062, M8438,
M8064 - M8067
Note: High byte is unused.
0x03
Change ASCII Input
Delimiter
Change ASCII mode End of Message
character. After response is mode slave will
change the delimiter.
0x04 Force Listen Only Mode
Switch slave to Listen Only Mode
Note: When the slave enters Listen Only
Mode, all active communication controls are
turned off. While the device is in this mode,
any MODBUS messages addressed to it or
broadcast are monitored, but no actions will
be taken and no responses will be sent.
0x0A
Clear Counters and
Diagnostic Register
Clear all counters and the diagnostic registers
0x0B Return Bus Message Count Read number of detected messages
0x0C
Return Bus Communication
Error Count
Read number of detected communication
errors
0x0D
Return Bus Exception Error
Count
Read number of detected exception
conditions
0x0E
Return Slave Message
Count
Read number of received requests
0x0F
Return Slave No Response
Count
Read "No Response" counter of the slave
0x10 Return Slave NAK Count Read NAK counter of the slave
0x11 Return Slave Busy Count Read "Busy" counter of the slave
0x12
Return Bus Character
Overrun Count
Read "Bus Character Overrun" counter of the
slave