Timer, Counter And Shift Register Instructions; Using Timers - Automationdirect.com DirectLOGIC DL205 Series User Manual

Chapter 5: Standard RLL Instructions - Timer, Counter and Shift Register

Timer, Counter and Shift Register Instructions

Using Timers

Timers are used to time an event for a desired length of time. The single input timer will time
as long as the input is on. When the input changes from on to off the timer current value is
reset to 0. There is a tenth of a second and a hundredth of a second timer available with a
maximum time of 999.9 and 99.99 seconds respectively. There is a discrete bit associated with
each timer to indicate that the current value is equal to or greater than the preset value. The
timing diagram below shows the relationship between the timer input, associated discrete bit,
current value, and timer preset.
0
X1
T1
Current
Value
There are those applications that need an accumulating timer, meaning it has the ability to
time, stop, and then resume from where it previously stopped. The accumulating timer works
similarly to the regular timer, but two inputs are required. The enable input starts and stops
the timer. When the timer stops, the elapsed time is maintained. When the timer starts again,
the timing continues from the elapsed time. When the reset input is turned on, the elapsed
time is cleared and the timer will start at 0 when it is restarted. There is a tenth of a second
and a hundredth of a second timer available with a maximum time of 9999999.9 and
999999.99 seconds respectively. The timing diagram below shows the relationship between
the timer input, timer reset, associated discrete bit, current value, and timer preset.
0
X1
X2
T0
Current
Value
Seconds
1 2 3 4
0 10 20 30
1/10 Seconds
Seconds
1 2 3 4
0 10 10 20
1/10 Seconds
5 6 7 8
40 50 60 0
5 6 7 8
30 40 50 0
DL205 User Manual, 4th Edition, Rev. B
X1
TMR
K30
Timer Preset
T1
X1
TMRA
K30
Enable
X2
Reset Input
1
2
3
4
5
6
T1
7
Y0
8
OUT
9
10
11
12
13
14
A
T0
B
C
D
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