Transfer Sequence Time Chart And Communication Time - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
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6.5

Transfer Sequence Time Chart and Communication Time

This section explains the communication time chart between the computer and the PLC.
As shown in the figures below, communication between the computer and the PLC is always executed after
"END". The scan time is extended by the communication time.
6.5.1 When computer reads data from PLC
Computer
Interface
PLC
Sequence
program
END
FX
FX , FX
2N 2NC
FX (FX), FX , FX
2 2C
6.5.2 When computer writes data to PLC
Computer
Interface
PLC
Sequence
program
D-54
E
N
Q
Waiting time
(TW)
S
T
X
This time is "0" when the message waiting time is
not set or when the waiting time is shorter than the
communication time with the CPU.
T
T T
0 1 2
Step 0 Step 0
END END
The PLC watches the time elapse. When it reaches the
transmission time, the PLC starts the transmission. If not,
the PLC evaluate the time elapse in the END process of
the next step.
PLC
, FX
3U 3UC
, FX , FX , FX
3S 3G 3GC
, FX , FX , FX
0N 1S 1N 1NC
E
N
Q
Waiting time
(TW)
Data is
written.
This time is "0" when the message waiting time is
not set or when the waiting time is shorter than the
communication time with the CPU.
T T
T
1 2
0
Step 0 Step 0
END END END
6.5 Transfer Sequence Time Chart and Communication Time
A
C
K
T T T
3 4 5
It should be the interval times in the following
table or more.
Step 0
END
Interval times
300 s
100 s
two scan times
T
3
Step 0
END
6 Control Procedures and Setting Methods