Mitsubishi Electric 700 Series Programming Manual page 87

Description of devices
(2) Present value update timing and accuracy in refresh system
1) The timer accuracy is +2 scan times independently of the used timer and scan
time.
2) The following shows the present value update timing and accuracy when the
10ms timer is used in a program where the scan time is 10ms or more.
Ladder example
Timer timing method
Scan time 25ms
OUT
END
T3
When external
input turns on
in hatched
range
OFF
X0
OFF
T3 coil
OFF
T3 contact
10ms timer
timing
Timing set
at END
T3 present
value
In Fig. 3.8, the time-out period of the 10ms timer T3 has the following errors.
*1 .......... 10ms timer error (+1 scan time)
*2 .......... Error produced by timer's input condition ON timing and OUT
The accuracy is +2 scan time (+0.05s in Fig. 3.8)
3) When the timer times out, its contact remains on until END even if the coil turns
off, and turns off at execution of the END instruction.
82
OUT
END T3
25ms 25ms
ON
ON
1 2 1 2
2
*2
1 scan
0
Fig 3.17 Timer Timing Method
T instruction's program position (+1 scan time)
T3 contact turns on 6s after X0 turns
on. (T3 is 10ms timer.)
OUT
END T3 END
25ms
3 1 2 1
2
3
0 3 3 3 2 5
6000ms
600 appears when monitored
on peripheral device.
OUT
END T3 END
25ms
ON
2 1 2 3
2
3
597 2 599 599 3 602
*1
1 scan
0