ABB ACSM1 Series, Firmware Manual

Page: 251 / 334

Standard function blocks
251
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 (LD) 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 -2147483648, the counter output remains
unchanged.
The status output (Q) is 1 if the counter output (CV) value < 0.
Example:
Inputs Counter input (CD): Boolean
Load input (LD): Boolean
Preset input (PV): DINT
Outputs Status output (Q): Boolean
Counter output (CV): DINT
CTU
(10049)
Illustration
Execution time 0.92 µs
LD CD PV Q CV
prev
CV
0 1 -> 0 10 0 5 5
0 0 -> 1 10 0 5 5 - 1 = 4
1 1 -> 0 -2 1 4 -2
1 0 -> 1 1 0 -2 1
0 0 -> 1 5 1 1 1 -1 = 0
1 1 -> 0 -2147483648 1 0 -2147483648
0 0 -> 1 10 1 -2147483648 -2147483648
CV
prev
is the previous cycle counter output value.
CTU
95
TLA1 1 msec (1)
>CU
R
PV
CV
CV(95)
Q
Q(95)