Structured Text Programming in Telepace Studio for SCADAPack

Quick Answer

SCADAPack E and x70 series support IEC 61131-3 Structured Text through Telepace Studio. ST is preferred for complex calculations, gas flow algorithms, and multi-state sequencing that would be cumbersome in ladder diagram.

When to Use ST

• Gas flow calculations with AGA equations
• Multi-well production sequencers
• Complex alarm logic with multiple conditions
• Data table operations and statistical calculations

Syntax Examples

// Gas flow calculation
IF DiffPressure > 0.0 AND StaticPressure > 14.0 THEN
    FlowRate := FlowCoeff * SQRT(DiffPressure * StaticPressure);
ELSE
    FlowRate := 0.0;
END_IF;

// Multi-well sequencer
CASE WellStep OF
    0: IF StartCommand THEN WellStep := 10; END_IF;
    10: OpenValve[WellIndex] := TRUE;
        IF ValveOpen[WellIndex] THEN WellStep := 20; END_IF;
    20: StartPump := TRUE;
        IF PumpRunning THEN WellStep := 30; END_IF;
    30: IF StopCommand THEN WellStep := 40; END_IF;
    40: StartPump := FALSE;
        OpenValve[WellIndex] := FALSE;
        WellStep := 0;
END_CASE;

For cross-platform ST comparison, see Allen-Bradley ST and IDEC WindLDR ST.