Structured Text; Function Block - Allen-Bradley Logix5000 Reference Manual

Chapter 3 Timer and Counter Instructions (TON, TOF, RTO, TONR, TOFR, RTOR, CTU, CTD, CTUD, RES)
152
Example:
When limit_switch1 goes from cleared to set, CUEnable is set for one scan and
the CTUD instruction increments the ACC value by 1. When
ACC ≥ PRE, the DN parameter is set, which enables the function block
instruction following the CTUD instruction.

Structured Text

CTUD_01.Preset := 500;
CTUD_01.Reset := Restart;
CTUD_O1.CUEnable := limit_switch1;
CTUD(CTUD_01);
counter_state := CTUD_01.DN;

Function Block

Rockwell Automation Publication 1756-RM003N-EN-P - October 2011