Mitsubishi FX3U-232-BD User Manual page 272

FX Series PLC User's Manual - Data Communication Edition
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7.13.2 Control procedures in on-demand function
This subsection explains the control procedures for the on-demand function.
When using ch2 in an FX
registers (D) according to the table below.
All PLCs except FX
FX and FX
3U
*1. FX , FX
0N
1) Control procedure in the PLC
Sending of on-demand data
Checks unit (word or byte) of
Writes data to be sent to data
Resets on-demand error
Starts on-demand function
Checks for sending error
When there
is error
D-70
or FX Series PLC, exchange special auxiliary relays (M) and special data
3U 3UC
and FX PLCs
3U 3UC
PLCs (ch1)
3UC
*1
M8127
M8128
M8129
D8127
D8128
, FX and FX PLCs do not support this device.
1S 1N 1NC
data to be sent
registers
When there is
no error
Sending is completed
FX
↔
It is checked whether M8129 is ON or OFF.
........
ON: Unit = byte (8-bit)
OFF: Unit = word (16-bit)
Data to be sent is written to data registers.
........
........ The on-demand error flag M8128 turns OFF.
(While M8128 is ON, the on-demand function is disabled.)
........ The head device (data register) number storing the on-
demand data is written to D8127, and the amount of data is
written to D8128.
When a request is accepted, M8127 is set to ON.
When sending is complete, M8127 turns OFF.
If the on-demand error flag M8128 is ON, it means that data
........
was not sent due to an error in the specified value to be sent.
7.13 On-demand Function
and FX PLCs (ch2)
3U 3UC
M8427
M8428
M8429
D8427
D8428
7 Commands