Mitsubishi Electric FX3U-232-BD User Manual page 323

FX Series PLC User's Manual - Data Communication Edition
Computer Link
2) Control procedure in the computer
Receiving of on-demand data
Judges whether receive data is
on-demand data or data given
by command execution.
Completion of receiving
3) Time chart when the on-demand function is requested
While the computer is sending data
PLC
[1] As soon as an on-demand request is given, the on-demand send processing signal M8127 turns ON.
[2] After receiving of command data (ENQ ~) from the computer is completed, the PLC sends on-demand
data.
[3] After the sending of on-demand data is complete, the PLC sends response data (STX ~) to the
command data (ENQ ~).
While the computer is receiving data
[1] As soon as an on-demand request is given, the on-demand send processing signal M8127 turns ON.
[2] After the sending of response data (STX ~) to the command data (ENQ ~) from the computer is
completed, the PLC sends on-demand data.
[3] After the receiving of on-demand data is complete, the computer sends response data (ACK ~) to the
sending of the response data (STX ~) from the PLC.
........
Data processing
E
N
Q
Computer side
PLC side
On-demand send processing
M8127
Writes data to be sent and
amount of data to be sent.
E
N
Q
Computer side
PLC side
On-demand send processing
M8127
Writes data to be sent and
PLC
amount of data to be sent.
To the on-demand data, the PLC adds "FE" as the PLC
number. Only when the PLC number of the received data is
"FE", the received data should be processed as on-demand
data.
A
C
[2] On-demand data
K
[3]
S
T
X
[1]
[3]
A
C
On-demand data
K
S
T
X
[2]
[1]
7 Commands
7.13 On-demand Function
A
B
C
D
E
F
G
H
I
Apx.A
D-81