4 - 7
4.1 MODBUS(R) Standard Function Support List
4
MODBUS(R) STANDARD FUNCTIONS
(3) List of MODBUS standard functions supported when accessing a
MELSECNET/H remote I/O station
The following MODBUS standard functions are available when the QJ71MB91
mounted on a MELSECNET/H remote I/O station makes access to the MELSECNET/
H remote I/O station.
: Supported : Supported with restrictions : Not supported
* 1 The access target is the MELSECNET/H remote I/O station.
When the MELSECNET/H remote master station is the access target, available functions are the
same as those shown in (2).
* 2 Accessing the MODBUS device that is not supported by the MELSECNET/H remote I/O station
results in error completion. (Exception code: 04
H)
If the access target is the MELSECNET/H remote master station, it can be assigned to the control
CPU device of the MELSECNET/H remote master station.
(Continued on next page)
Table4.3 MODBUS standard functions available for access to MELSECNET/H remote I/O station
Function
code
(Sub code)
Sub-function
Code
Function
Master function
Slave function
*1
Automatic
communication
function
MBRW
instruction
MBREQ
instruction
01 - Read coils
*2
02 - Read discrete inputs
*2
03 - Read holding registers
*2
04 - Read input registers
*2
05 - Write single coil
*2
06 - Write single register
*2
07 - Read exception status
*2
To Next Page
Loading...
Need help?
General
