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Ramp Generator Starting Point

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  • Ramp Generator Starting Point

    I am have difficulty getting the ramp generator to start my ramp at a certain value. I want to use the ramp generator to ramp the setpoint value of a PID loop that I have setup. The system controls pressure and will be sitting at some pressure value. I want to be able to ramp up or down from the systems current pressure. The min and max of the ramp generator are set at 0 and my maximum system pressure. I need to be able to ramp in between these values. I am disabling the ramp when I reach a specified pressure. Everything works except for the starting point.

    I have tried copying the system pressure reading to the output tag of the ramp generator, but it will not except the update, the value of the tag remains zero. I have tried updating the tag before enabling and after enabling the ramp generator and nothing seems to work.

  • #2
    I think you will need to use a tag for both the Min and Max settings. When you want to initiate the ramp generator, you will want to load the desired starting value into the Min tag (if you are ramping up) or in the Max tag if you are ramping down.


    • #3
      Or just use a RMP instruction and limit instruction. You could use the limit on the commanded set point also so the operator could never enter higher or lower than your limit.

      Click image for larger version  Name:	Ramp.JPG Views:	1 Size:	67.7 KB ID:	120265
      Last edited by techme; 01-25-2019, 04:34 PM.