Chapter 5 Power Supply / CPU
5- 10
In general, its operation is same as on-delay timer. Only the difference is the current value will not be clear when the
input condition of TMR instruction is turned off. It keeps the elapsed value and restart to increase when the input
condition is turned on again. When the current value reaches preset value, the timer output relay is turned on.
The current value can be cleared by the RST instruction only.
4) Monostable timer
In general, its operation is same as off-delay timer. However, the change of input condition is ignored while the timer is
operating (decreasing). When current value reaches preset value the timer output relay is turned off and current value is
cleared.
Timer input condition
Timer output relay
Preset value
Current value
Timer reset input
Timer input condition
Timer output relay
Preset value
Current value
t0 t1 t2 t5
t1
t0 t2 t5+PT
t5
t3
PT = (t1-t0)+(t3-t2)
t4
t0 t1 t2 t3 t4
t0
t1
t2
t0+PT
t0
t2+PT
t2
t4+PT
t4
t4