Modbus Standard Functions And Modbus Devices; Modbus Standard Function - Mitsubishi Electric NZ2FTGN User Manual

11.7
MODBUS Standard Functions and MODBUS
Devices
The NZ2FT-MT uses the MODBUS standard function to specify a MODBUS device and access the master station.
The MODBUS device can be specified as a bit address for reading/writing registers in units of bits and a register address for
reading/writing in units of words.
Access method
For how to read/write registers during automatic communication (constant periodic communication), refer to the following.
• Master station is the RJ71EN71: Simple CPU communication function ( MELSEC iQ-R Ethernet User's Manual
(Application))
• Master station is the QJ71MT91: Automatic communication parameter setting ( MODBUS/TCP Interface Module User's
Manual (Details))
For how to read/write registers using a dedicated instruction when communicating at any time, refer to the following.
• Master station is the RJ71EN71: ECPRTCL instruction ( MELSEC iQ-R Ethernet User's Manual (Application))
• Master station is the QJ71MT91: MBRW and MBREQ instructions ( MODBUS/TCP Interface Module User's Manual
(Details))

MODBUS standard function

The following table lists the MODBUS standard functions supported by the NZ2FT-MT for each master station function.
: Support function, : Unsupported function
Function code Function
name
(Hexadecimal) (Decimal)
01H 1 Read coils
02H 2 Read
inputs
03H 3 Read
holding
register
areas
04H 4 Read input
register
areas
05H 5 Write
single coil
Processing Master module: RJ71EN71
description
Simple CPU
communication

Reads the status
(on/off) of one or
more coils.
Specified target:
Bit address of
read/write area

Reads the status
(on/off) of one or
more inputs.
Specified target:
Bit address of
read-only area

Reads one or
more holding
register values.
Specified target:
Register address
of read/write
area
Reads one or 
more input
register values.
Specified target:
Register address
of read-only area

Writes a value
(on/off) to a
single coil.
Specified target:
Bit address of
read/write area

11.7 MODBUS Standard Functions and MODBUS Devices

Master module: QJ71MT91
ECPRTCL Automatic
instruction communication
 
 
 
 
 
MBRW MBREQ
instruction instruction
 
 
 
 
 
11 NZ2FT-MT
307
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