Mitsubishi MELSEC-A series Programming Manual

7. APPLICATION INSTRUCTIONS
7 − 74
MELSEC-A
(8) Status of registration in the communication request registration areas can be
confirmed by M9081 and D9081.
M9081: Turns ON when the communication request registration areas are full.
Turns OFF when there is a vacant area.
D9081: Stores the number of vacant areas in the communication request
registration areas.
M9081 and D9081 can therefore be used as handshake signals for execution of
instructions.
(9) If the FROM(P)/DFRO(P) instructions are executed to a remote terminal module
which is communicating with other module, execution of the instructions is again
performed to the same remote terminal module immediately after the
processing being executed.
Execution Conditions
Operation Errors In the following cases, operation error occurs and the error flag turns ON.
• When the station number specified at (n1) is not of a remote terminal.
• When "n3" points which start with the device specified at (D1) exceed the
specified device range.
• When the device specified at (D1) is not a usable device.
Program Examples FROM , PRC
A program which reads data of 1 word from address 18 of buffer memory of the
AD61C (head station number 1) to D10 when X0 is turned ON.
Device specified at (D2)
(Communication complete flag)
OFF
ON
Executed every
completion of
communication
Executed every
completion of
communication
Executed only once
Executed only once
P
Read command
Device specified at (D2)
(Communication complete flag)
K K K
FROM 1 18 D10 1
PRC M0 Y000
0
X000
……... M0 turns ON when communication
processing is completed.
• Coding
0 LD X000
1 FROM K1 K18 D10 K1
10 PRC M0 Y000
17 END

Mitsubishi MELSEC-A series Specifications

General

Brand	Mitsubishi
Model	MELSEC-A series
Category	Controller
Language	English