PLC code using Concept

Discussion in 'Programmer's Corner' started by Humphrey Matiza, Dec 12, 2017.

  1. Humphrey Matiza

    Thread Starter New Member

    Dec 12, 2017
    1
    0
    I have just joined a boiler making company and I am required to write plc code for the boiler water level regulation. The new instrument I added is a differential pressure cell between the boiler pressure and the pump pressure. The differential pressure cell produces a 4-20mA signal. We aim to increase the pump pressure to be always above the boiler pressure. I am supposed to write the code using concept. Any heads up
     
  2. rthomas12

    Member

    Dec 6, 2016
    32
    3
    Pump pressure or the circulation rate (gpm)? Match the 4-20 signal to the range of the designed pump curve. Then output a digital signal to the VFD/motor controller with the same scaling.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    15,876
    4,651
    What make PLC?
    Presumably you have the 4-20ma extension unit for the PLC?
    Max.
     
  4. Picbuster

    Active Member

    Dec 2, 2013
    791
    97
    I assume that the zero is @ 12mA + or - 8 indicating direction.
    What I do not understand:
    When do you stop the pump (detected from this differential measurement) ?
    Is this an open boiler?
    The temperature is very important in a closed system boiling steam could go up to 400++ degree @ 100Bar or more so pump must be able to handle.
    This call for the question: how to measure the water level pressure is not enough?

    Picbuster
     
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