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MELSEC-F
WHEN COMMUNICATING DATA USING THE MC PROTOCOL9
9 - 15
9.2 List of Commands and Functions for The MC protocol
The following table lists the commands and functions when an external device
accesses the PLC.
*1 When the double word data is read using the user program, etc., read out the 32bit data at once.
Function
-
Command/response type Processing
Number of points
processed per
communication
Device
memory
Batch read
Bit units 00
H Reads bit devices (X, Y, M, S, T, C) in 1-point units. 256 points
Word units 01
H
Reads bit devices (X, Y, M, S, T, C ) in 16-point units. 32 words (512 points)
Reads word devices (D, R, T, C ) in 1-point units. (*1) 64 points
Batch write
Bit units 02
H Writes to bit devices (X, Y, M, S, T, C ) in 1-point units. 160 points
Word units 03
H
Writes to bit devices (X, Y, M, S, T, C ) in 16-point units. 10 words (160 points)
Writes to word devices (D, R, T, C ) in 1-point units. 64 points
Test
(Random write)
Bit units 04H
Sets/resets bit devices (X, Y, M, S, T, C) in 1-point units
by arbitrarily designating the devices and device number.
80 points
Word units 05
H
Sets/resets bit devices (X, Y, M, S, T, C) in 16-point units
by arbitrarily designating the devices and device number.
10 words (160 points)
Sets/resets word devices (D, R, T, C) in 1-point units by
arbitrarily designating the devices and device numbers.
Not applicable for 32 bit devices from C200 to C255.
10 points
PLC control
Remote RUN 13
H
Requests the remote RUN/STOP to PLC.
Remote STOP 14
H
PLC model name read 15H Reads PLC model name code.
Loop test 16
H
Returns the character received from the other node to
that node with the data as it is.
254 bytes