ABB CL Series Applications Manual page 117

Wiring with the logic relay
114
Determining counter frequency
The maximum counter frequency depends on the length of
the circuit diagram in the logic relay. The number of
contacts, coils and rungs used determines the run time (cycle
time) required to process the CL circuit diagram.
Example: When using CL-LST.C12DC2 with only three rungs
for counting, resetting and outputting the result via the
output, the counter frequency may be 100 Hz.
The maximum counter frequency depends on the maximum
cycle time.
The following formula is used to determine the maximum
counter frequency:
1
f = x 0.8
c
2 x t
c
f = maximum counter frequency
c
t = maximum cycle time
c
0.8 = correction factor
Example
The maximum cycle time is t
1
f = x 0.8 = 100 Hz
c
2 x 4 ms
1SVC 440 795 M0100
= 4000 ms (4 ms).
c