Mitsubishi Electric MELSEC iQ-R Series User Manual page 462

Accuracy of timers
This sections describes the accuracy of timers.
■Timer (T/ST)
The scan time value measured by the END instruction is added to the current value when the OUT T instruction is executed.
If the timer coil is turned off when the OUT T instruction is executed, the current value is not updated. The maximum
response accuracy of the timer (the time duration from capture of an input (X) to output of it) is "2 scan time + timer time limit
setting".
Ex.
Timer limit setting = 10ms, setting value of T0 = 8 (10ms  8 = 80ms), scan time = 25ms
Program
Measurement at
10ms interval
Count by the END
instruction
Current value of T0
External input of X0
OFF
OFF
X0 of the CPU
module
OFF
Coil of T0
OFF
Contact of T0
Scan time
(1) Accuracy from when the coil of the timer turns on until when the contact of the timer turns on
- (1 scan time + timer limit setting) to (1 scan time)
(2) Timing on when the coil of the timer turns on
(3) Input fetching timing
27 DEVICES
460
27.3 User Device
END END END
processing processing processing
2 3
1 2 1 1 2
2 3
0+2=2
ON
ON
ON
25ms 25ms 25ms
(1)
(2)
(3)
END END
processing processing
1 2 3 1 2 1
2 3 2
2+3=5 5+2=7 7+3=10
ON
25ms 25ms 25ms
K8
X0
T0
END
processing
2 3
3