Mitsubishi Electric QJ71MB91 User Manual page 252

9
PROGRAMMING
9
- 23 9.2 Program Example for Normal System Configuration
9.2.3 When using the automatic communication function and the communication by dedicated instructions on the same channel
2) Program example for dedicated instruction
This section provides an program example in which a dedicated instruction
(MBRW) is executed while automatic communication of Automatic
communication parameter 1 on channel 2 is in ready status.
In the program example on the next page, the following device read/write is
executed to the holding register on the slave (Station No. 1) on channel 2.
QJ71MB91
(master)
QJ71MB91
(master)
Device memory
D100
100 points
D199
W0000
32 points
W001F
Figure 9.23 Processing of program example
MODBUS
slave device
(station No.1)
CH2 (RS-422/485)
MODBUS
slave device
MODBUS device
32 points
100 points
400500
400531
411000
411099
(Continued on next page)