Logix5000 Controllers General Instructions - SLAC Confluence

Special Instructions (FBC, DDT, DTR, PID) 515Structured TextIF (Local:0:I.Ch0Fault) THENTIC101.SWM [:=] 1;ELSETIC101.SWM := 0;END_IF;IF (Local:0:I.RollingTimestampPreviousTimestamp) OR(Local:0:I.Ch0Fault) THENEND_IF;PreviousTimestamp := Local:0:I.RollingTimestamp;PID(TIC101,Local:0:I.Ch0Data,Local:0:I.Ch1Data,Local:1:O.Ch0Data,0,Local:1:I.Ch0InHold,Local:1:I.Ch0Data);Bumpless restartThe PID instruction can interact with the 1756 analog output modulesto support a bumpless restart when the controller changes fromProgram to Run mode or when the controller powers up.When a 1756 analog output module loses communications with thecontroller or senses that the controller is in Program mode, the analogoutput module sets its outputs to the fault condition values youspecified when you configured the module. When the controller thenreturns to Run mode or re-establishes communications with theanalog output module, you can have the PID instruction automaticallyreset its control variable output equal to the analog output by usingthe Inhold bit and Inhold Value parameters on the PID instruction.Publication 1756-RM003I-EN-P - January 2007