CONTREX CX-1200 - Manual (Page 197)

5 - 104
PLC TIMERS
The are four timers that work in conjunction with the PLC. Each timer can be set up to generate a pulse. The
timers operate with 1 millisecond resolution. However, when the timer times out and the timer output becomes
active, the PLC program may not react for another millisecond because of the two millisecond scan time.
Therefore, enter the time values at “1” or “2” milliseconds shorter than you actually need to compensate. The
timer outputs reflect the operation of an On-delay timer. If you need an Off-delay operation, use the “NOT”
(complement) of the output. Timer 4, retains the accumulated time even when the Enable is deactivated.
The operation of each timer is dictated by their respective delay and on-time parameters. The following shows
a typical time-trace of the Tmr1 Out when Tmr1 En changes from “0 ”to “1”. Tmr1 Delay (CP-410) equals
“0.100” Seconds and Tmr1 on Tm (CP-411) equals “-1”.
1
0
Tmr1 EN
1
0
Tmr1 OUT
0.100 Sec
The following shows a time-trace of the Tmr1 Out when Tmr1 En changes from “0” to “1”. Tmr1 Delay (CP-
410) equals “0.100” Seconds and Tmr1 on Tm (CP-411) equals “0.050” Seconds.
1
0
Tmr1 EN
1
0
Tmr1 OUT
0.100 Sec
0.050 Sec