Timer - Mitsubishi Electric MELSEC iQ-R Series User Manual

Timer

This device starts measurement when the timer coil is turned on. When the current value reaches a setting value, time is up
and the contact is turned on. This timer is an up-timing type device and therefore the current value matches a setting value
when the timer time is up.
Types of timers
There are two types of timers: timer (T) which retains the current value in 16-bit units and long timer (LT) which retains it in 32-
bit units. The timer (T) and the long timer (LT) are different devices and the number of device points can be set for each of
them. In addition, there are the retentive timer (ST) and the long retentive timer (LST), both of which retain the current value
* 1
even if the coil is turned off.
Types of timers
Timer Current value = 16 bits
Current value = 32 bits
*1 For the timer (T)/long timer (LT), the current value returns to 0 when the coil is turned off.
■Timer (T)
This device starts measurement when the coil of the timer is turned on. When the timer current value matches a setting value,
time is up and the timer contact is turned on. When the timer coil is turned off, the current value returns to 0 and the timer
contact is turned off.
X0 K10
T0
1)
T0
Y10
2)
■Long timer (LT)
This device can count from 0 to 4294967295 to measure the time. If the measuring unit is set to 0.01ms, the measurable time
range of this device is from 0 to about 11.9 hours. The current value of the long timers is updated by adding a difference of the
counter which is used in the system when the OUT LT instruction is executed. Proper time can be measured even when the
coil instruction of the long timer cannot be executed once per scanning because the counters used in the system count
asynchronously with scanning. When the long timer coil is turned on, measurement starts and when the long timer current
value matches a setting value, time is up and the long timer contact is turned on. When the long timer coil is turned off, the
current value returns to 0 and the long timer contact is turned off.
X0
K100
LT0
1)
LT0
Y10
2)
*1 This figure shows the example when the long timer time limit value setting is 0.01ms.
• The long timer contact is turned on in the next or subsequent coil execution after the long timer coil is turned
on. The long timer contact is not turned on simultaneously when the long timer coil is turned on.
• The long timer (LT) can be used in interrupt programs. ( Page 115 Interrupt Program)
Timer (T)
Retentive timer (ST)
Long timer (LT)
Long retentive timer (LST)
ON
X0
OFF
ON
Coil of T0 (1))
OFF
1 second
Contact of
OFF
T0 (2))
ON
X0
OFF
ON
Coil of LT0 (1))
OFF
Contact of
OFF
LT0 (2))
Low-speed timer
High-speed timer
Low-speed retentive timer
High-speed retentive timer
ON
ON
1ms
27
27 DEVICES
457
27.3 User Device