Timers (T) - Mitsubishi Electric MELSEC-Q Series User Manual

10 DEVICES

10.2.10 Timers (T)

[Ladder example]
[Time chart]
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Timers are of a forward timer type, with the time measurement beginning when the coil
switches ON, and ending (time out) when the present value exceeds the setting value.
The present value matches the setting value when a "time-out" occurs.
There are two types of timers: a low/high-speed that allows the current value to return
to "0" when a timer coil switches OFF, and a retentive timer that retains the current
value even when a timer coil switches OFF.
Timers Timers
Retentive timers
With a timer setting (instruction format), a device is assigned for a low-speed timer or
high-speed timer. The OUT T0 instruction is used to assign a device for a low -speed
timer. The OUTH T0 instruction is used to assign a device for a high-speed timer.
With a timer setting (instruction format), a device is assigned for a low-speed retentive
timer or high-speed retentive timer. The OUT T0 instruction is used to assign a device
for a low-speed retentive timer. The OUTH T0 instruction is used to assign a device for
a high-speed retentive timer.
Low-speed timers
(1) Definition
(a) Low-speed timers are those that are only operative while the coil is ON.
(b) The time measurement begins when the timer's coil switches ON, and the
contact switches ON when a "time-out" occurs. When the timer's coil
switches OFF, the present value becomes "0", and the contact switches
OFF.
X0
X0 OFF
T0 coil OFF
T0 contact OFF
(2) Measurement units
(a) The default time measurement units setting for low-speed timers is 100 ms.
(b) The time measurement units setting can be designated in 1 ms units within a
1 ms to 1000 ms range.
This setting is designated in the "PLC system settings" in the PLC
parameter setting.
Low-speed timers
High-speed timers
Low-speed retentive timers
High-speed retentive timers
When X0 switches ON, the T0 coil switches ON, and the
K10
contact switches ON 1 second later. (The low-speed timer
T0
measures time in 100 ms units.)
ON
ON
1 Sec.
ON
MELSEC-Q
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