Counters; Data Required For Counter Function Blocks - GE PACSystems RX7i Cpu Programmer's Reference Manual

4.7 Counters

Function Mnemonic Description
Down Counter DNCTR
Up Counter UPCTR
4.7.1

Data Required for Counter Function Blocks

GFK-2950C
Counts down from a preset value. The output is ON whenever the
Current Value is  0.
Counts up to a designated value. The output is ON whenever the
Current Value is  the Preset Value.
Do not use two consecutive words (registers) as the
starting addresses of two counters. Logic Developer
PLC does not check or warn you if register blocks
overlap. Timers will not work if you place the current
value of a second timer on top of the preset value for
the previous timer.
February 2018
Chapter 4. Ladder Diagram (LD) Programming
Warning
133