ABB ACSM1 Manual page 365

Operation The counter output (CV) value is increased by 1 if the counter input (CU) value changes
from 0 -> 1 and the reset input (R) is 0 and the load input (LD) is 0.
The counter output (CV) value is decreased by 1 if the counter input (CD) changes from
0 -> 1 and the load input (LD) is 0 and the reset input (R) is 0.
If the load input (LD) is 1, the preset input (PV) value is stored as the counter output
(CV) value.
The counter output (CV) is reset to 0 if the reset input (R) is 1.
If the counter output has reached its minimum or maximum value, -32768 or +32767,
the counter output remains unchanged until it is reset (R) or until the load input (LD) is
set to 1.
The up counter status output (QU) is 1 if the counter output (CV) value > preset input
(PV) value.
The down counter status output (QD) is 1 if the counter output (CV) value < 0.
Example:
CU
0 -> 0
0 -> 0
0 -> 0
0 -> 0
0 -> 0
0 -> 0
0 -> 0
0 -> 0
0 -> 1
1 -> 1
1 -> 1
1 -> 1
1 -> 1
1 -> 1
1 -> 1
1 -> 1
CV
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Inputs Up counter input (CU): Boolean
Down counter input (CD): Boolean
Reset input (R): Boolean
Load input (LD): Boolean
Preset input (PV): INT
Outputs Counter output (CV): INT
Up counter status output (QU): Boolean
Down counter status output (QD): Boolean
CD R LD
0 -> 0 0 0
0 -> 0 0 1
0 -> 0 1 0
0 -> 0 1 1
0 -> 1 0 0
1 -> 1 0 1
1 -> 1 1 0
1 -> 1 1 1
1 -> 0 0 0
0 -> 0 0 1
0 -> 0 1 0
0 -> 0 1 1
0 -> 1 0 0
1 -> 1 0 1
1 -> 1 1 0
1 -> 1 1 1
is the previous cycle counter output value.
PV QU QD CV
2 0 1 0
2 1 0 0
2 0 1 2
2 0 1 0
2 0 1 0
2 1 0 -1
2 0 1 2
2 0 1 0
2 0 0 0
2 1 0 1
2 0 1 2
2 0 1 0
2 0 1 0
2 1 0 -1
2 0 1 2
2 0 1 0
Standard function blocks
365
CV
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0
2
0
0
0 - 1 = -1
2
0
0
0 + 1 = 1
2
0
0
0 - 1 = -1
2
0
0