Updn Function Block - Honeywell UMC800 Reference Manual

2.76 UPDN Function Block

Description
The UPDN label stands for UP/DOWN Counter. This block is part of the Counters/Timers category. It
looks like this graphically on the Control Builder:
Function
The output counts the number of rising edge logic transactions on the input to the block up to a preset value
(RPRE or LPRE). When the preset value is reached, a logic output(PREI) is enabled for one scan cycle. A
Reset input (RST) resets the block. Value may be set to increase to the preset value or decrease from the
preset value.
Inputs
^X = Positive Edge Detect Count Input
RPRE = Remote Preset
RST = ON resets the count
CNTDN = ON counts down
Outputs
OUT = Output
PREI = Preset Indicator
3/99 Function Block Reference Guide
Function Blocks
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