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MELSEC-Q
10 DEDICATED INSTRUCTIONS
10 DEDICATED INSTRUCTIONS
The dedicated instructions make programming easy for use of the intelligent function
module functions.
10.1 Dedicated Instruction List and Available Devices
(1) Dedicated instruction list
The following table indicates a list of dedicated instructions supported by the
QJ71MT91.
Dedicated
Instruction
Description Reference
MBRW
Reads and writes the MODBUS
R
device data from and to
the slave.
Section 10.2
MBREQ
Communicates with the slave in the request message
format of any PDU (protocol data unit).
Section 10.3
Interlock for dedicated instruction execution
Execute the dedicated instruction with the I/O signals in the following status.
X0
X3
X0 :
X3 :
Dedicated
instruction
Module READY
Basic parameter setting
existence
POINT
Until completion of the dedicated instruction execution, do not change the data
(control data, argument, etc.) specified for the dedicated instruction.
(2) Available devices
The following devices are available for the dedicated instructions:
Internal devices
Bit
1
Word
File register
X, Y, M, L, F, V, B
T, ST, C, D, W
R, ZR
1: Word device bit designation can be used as bit data.
Word device bit designation is done by designating Word device . Bit No. .
(Designation of bit numbers is done in hexadecimal.)
For example, bit 10 of D0 is designated as D0.A .
However, there can be no bit designation for timers (T), retentive timers (ST) and
counters (C).
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