See!tHow

Tag: PLC Program

  • Ladder Logic Bit Instructions – Part 2

    Ladder Logic Bit Instructions – Part 2

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    4. Positive Transition or One Shot Rising (OSR) Edge Positive Transition instruction becomes Logic high (State”1″) only for the moment, “Tagname” value transit from Logic low(0) to Logic High(1). Note: The name Positive transition or OSR is depends on the PLC manufacturer. Refer the following Examples, The moment when Tagname transits from “0” to “1”,…

  • Understanding the PLC system

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    PLC program is the control logic that is stored inside the PLC memory to perform the predefined actions to control the system. The above image shows how PLC control system is interacting with field/system with help of IO modules and PLC Program. Following are the important parts of the typical PLC program, Hardware Configuration –…

  • OFF DELAY TIMER – TOF

    OFF DELAY TIMER – TOF

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    OFF Delay Timer (TOF) delays the OFF status its Output bit (DN bit). OFF Delay Timer makes Done (DN) bit to State “1” once it is enabled. DN bit Remains in State “1” till the timer is enabled. Once the timer input is disabled, TOF Timer keeps its output to State “1” till the time…

  • ON DELAY TIMER – TON

    ON DELAY TIMER – TON

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    ON – Delay Timer delays the Output (Done bit) to become state “1” for the predefined PRESET time. Following Video shows the operation of TON – ON delay timer. All the timer blocks having following Common parameters, EN – Enable bit, ON Logic which enables the Timer Block. DN – Done bit, This the output…