4 - 9
4.1 MODBUS(R) Standard Function Support List
4
MODBUS(R) STANDARD FUNCTIONS
: 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. (Exeption 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.
POINT
When the QJ71MB91 is mounted to a MELSECNET/H remote I/O station, switch
the access target using the Access target (when mounted to MELSECNET/H
remote I/O station) in the buffer memory (address: 000E
H).( Section 7.3.5)
Table 4.3 MODBUS standard functions available for access to MELSECNET/H remote I/O station (continued)
Function
code
(Sub code)
Sub-function
code
Function
Master function
Slave function
*1
Automatic
communication
function
MBRW
instruction
MBREQ
instruction
11 -
Get communications event
counter
12 - Get communications event log
15 - Write multiple coils
*2
16 - Write multiple registers
*2
17 - Report slave ID
20(6) - Read file record
21(6) - Write file record
22 - Mask write register
*2
23 - Read/Write multiple registers
*2
24 - Read FIFO queue
43 - Read device identification