Logix5000 Controllers General Instructions - SLAC Confluence

658 Function Block AttributesProgram request inputs are not normally cleared by the instructionbecause these are normally wired as inputs into the instruction. If theinstruction clears these inputs, the input would just get set again bythe wired input. There might be situations where you want to useother logic to set the Program requests in such a manner that youwant the Program requests to be cleared by the instruction. In thiscase, you can set the ProgValueReset input and the instruction willalways clear the Program mode request inputs when it executes.In this example, a rung of ladder logic in another routine is used toone-shot latch a ProgAutoReq to a PIDE instruction when apushbutton is pushed. Because the PIDE instruction automaticallyclears the Program mode requests, you don’t have to write any ladderlogic to clear the ProgAutoReq after the routine executes, and thePIDE instruction will receive only one request to go to Auto everytime the pushbutton is pressed.When the TIC101AutoReq Pushbutton is pressed, one-shot latch ProgAutoReq for the PIDE instruction TIC101.TIC101 has been configured with the ProgValueReset input set, so when the PIDE instruction executes, itautomatically clears ProgAutoReq.Publication 1756-RM003I-EN-P - January 2007