Attention

IronPLC supports IEC 61131-3 Structured Text excluding I/O mapping.

R_TRIG

Rising edge detector. Output Q is TRUE for one scan cycle when the input CLK transitions from FALSE to TRUE.

IEC 61131-3

Section 2.5.2.3.2

Support

Supported

Inputs

Name

Type

Description

CLK

BOOL

Signal to monitor for rising edge

Outputs

Name

Type

Description

Q

BOOL

Edge output (TRUE for one scan on rising edge)

Behavior

The function block stores the previous value of CLK. When CLK transitions from FALSE to TRUE, the output Q is set to TRUE for one scan cycle. On all subsequent scans where CLK remains TRUE, Q is FALSE. When CLK is FALSE, Q is always FALSE.

Example

This example detects a rising edge. The input starts TRUE, so Q is TRUE on the first scan (transition from the default FALSE to TRUE).

See Also

  • F_TRIG — falling edge detector