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PID Time Proportionaing Control Analogue Output to SSR

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  • #16
    If you google heater pid or temperature controller pid you will find various controllers. The one I would look for would be a kit with thermocouple, controller and a ssr capable to provide enough current for the heating element you have. The controller will provide the Pwm signal to the ssr, and all comes self-reliant. Sometimes the controller provides one or two alarm contacts to interface with the plc.

    to match your exact needs, it is best that you do the specs checkup yourself

    i would like to add this: the big issue of all pid control systems is that they do not account for system inertia. For this reason, some work well close to set value ( farther the process value is, more chance the system will loose control) while others manage well to reach the set value, but then keep over and undershooting, they oscillate around as if they canít provide fine control. In these two situations, either the pid can handle a low inertia or a high inertia, but not both.

    a real servo controller needs to answer next questions:
    1. Is the process moving towards set value or against?
    2. Is the process advancing too slow/steady or too fast?

    A pid system fails to answer the second question correctly because it tends to overlook the variation of process inertia. I will stop here because I donít want to monopolize or hijack your attention from the problem.
    Last edited by Alexandru; 11-19-2018, 08:20 PM.