Standard Function Blocks

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The IEC-61131-3 standard defines a number of function blocks, which are supported in Fernhill SCADA:

Function Block Type Keywords Explanation
Bistable SR, RS Set and reset dominant bistables.
Edge Detector R_TRIG, F_TRIG Rising and falling edge detectors.
Up Counter CTU Counts up from zero to a preset value.
Down Counter CTD Counts down from a preset value to zero.
Pulse Timer TP Generate a fixed duration pulse.
On Delay Timer TON Turn an output on after a delay.
Off Delay Timer TOF Turn an output off after a delay.

Note: Standard Function Blocks require Fernhill SCADA Version 1.2 or later.

Further Information

Common Elements

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For the meaning of terms used in Fernhill SCADA.