Modified PSR

Discussion in 'General Electronics Chat' started by kazintsky, Nov 20, 2013.

  1. kazintsky

    Thread Starter New Member

    Nov 20, 2013
    Hello ladies and gentlemen,

    Im an electrical/Instrument apprentice been given the task to design a control loop of some description. The loop ill be making is a temp bath to be filled to desired level and controlled at desired temp using as much automated equipment as possible. I will also be using a PLC Ge Fanuc 90-30 which has inbuilt PID controller to assist in the automation (just fyi)

    A question but first ill run through the setup that relates to my questions for you all:

    Small tank to be filled with water. Inside said tank will be a heating element. Im trying to learn as much as I can about control here so thermostats and temperature switches are boring. (case you were wondering)

    I don't know much about the PSR25. And im told its a Triac which will behave the same as a Pulse width modulator, exception its for an AC circuit. i.e it chops up the sine wave and is essentially removes the need for switching/thermostats and the consequential temperature setpoint overshoots/undershoots that come with on/off control

    My plan is to couple the PSR25 and the Filter to a heating element And Instead of using the prescribed potentiometer I'm hoping to use a Resistance transmitter to provide automatic feedback for the PSR circuit. I have a WeidMuller resistance transmitter - mA in, resistance out

    question 1: with this setup can anybody point out any flaws or provide some direction - The PLC has an inbuilt PID controller that can receive a temperature input and the resistance transmitter can feed into the PSR and tell the element to cool down.... Is there any flaw in my line of thinking here? any geniuses out there care to comment?

    if this is correct i'll need an Neg. Temp. Coefficient RTD/Transmitter. Can someone confirm this?

    Question 2: can I get away with just a CPU fan for cooling? if not -> where can I find a heatsink?

    Q3: please feel free to offer your knowledge on PSR25 (I don't really know how it works exactly) or any hints or traps to avoid. or suggestions.... anything
    Last edited: Nov 20, 2013