ABB ACSM1 - Counters; Ctd

Standard function blocks
361
Counters
CTD
(10047)
Illustration
Execution time 0.92 µs
Operation The counter output (CV) value is decreased by 1 if the counter input (CD) value
changes from 0 -> 1 and the load input (LD) value is 0. If the load input value is 1, the
preset input (PV) value is stored as the counter output (CV) value. If the counter output
has reached its minimum value -32768, the counter output remains unchanged.
The status output (Q) is 1 if the counter output (CV) value <
0.
Example:
Inputs Load input (LD): Boolean
Counter input (CD): Boolean
Preset input (PV): INT
Outputs Counter output (CV): INT
Status output (Q): Boolean
CTD
93
TLA1 1 msec (1)
LD
>CD
PV
CV
CV(93)
Q
Q(93)
LD CD PV Q CV
prev
CV
01 -> 010 05 5
0 0 -> 1 10 0 5 5 - 1 = 4
11 -> 0-2 14 -2
10 -> 11 0-2 1
0 0 -> 1 5 1 1 1 -1 = 0
1 1 -> 0 -32768 1 0 -32768
0 0 -> 1 10 1 -32768 -32768
CV
prev
is the previous cycle counter output value.