UP/DOWN COUNT (UP/DOWN COUNTER)

An ON level on the FORCE PRESET input enables the UP/DOWN COUNTER to be loaded with the counter number available at the PRESET input. This input can be connected to the NUM constant, to an analog input AI or to any other output on a function block which sends an INTEGER type value.

In the UP/DOWN COUNTER function, an edge from OFF to ON on the UPCOUNT input increments the counter as long as a similar edge on the DOWNCOUNT input decrements the counter.

When the counter number is reached, the OUTPUT changes to the ON state and remains ON as long as this counter number is greater than or equal to the PRESET value. If the transitions on the DOWNCOUNT input cause the counter number to fall below the PRESET value, the OUTPUT changes to the OFF state.

The CURRENT COUNTER VALUE stops at 32767 in UPCOUNTING mode and at -32768 in DOWNCOUNTING mode. The counter can be re-started using commands on the RESET TO ZERO or FORCE PRESET inputs.

As long as the RESET TO ZERO input is at 1, the OUTPUT remains in the OFF state. If the RESET TO ZERO input changes to the OFF state, up/down counting restarts at zero.

The UPCOUNT, DOWNCOUNT, RESET TO ZERO and FORCE PRESET inputs and the OUTPUT are digital.

The PRESET input is an INTEGER input.

This function has one additional INTEGER type output:

CURRENT COUNTER VALUE: Current up/down count value

This value is displayed in the "Simulation" and "Monitoring" modes.

Parameterisation box/Comments tab

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