Temperature PID Loop Blog

Things to Remember When Setting Up a Temperature PID in Siemens TIA Portal

Blog post by Joe Palace, Senior Electrical Engineer

Good common practices and tips when using a Siemens PID Temperature Technology object to control your heat device inside of your Siemens PLC program.

  • Before doing anything, you want to pick the correct thermal device that will be used to measure the temperature device. Is it a thermal couple, a thermistor, a resistor? With that, set up the correct parameters and units (Fahrenheit or Celsius). This is found in the analog card properties, under the Hardware device configuration
  • Set the Cyclic interrupt, OB30, to a reasonable interrupt time, 100 – 500ms
  • Your technology object, the PID FB, should always be enabled
  • Before starting the tuning algorithm, determine what tuning mode will be used
    • Pre-tuning – used if the temperature difference between actual and setup temperature is greater than 20 degrees
    • Fine Tuning – used when the temperature difference between actual and setup are within a few degrees

* Note: You might want to manually start the PID to start warming up the device before switching to Pre-Tune or Fine Tune. Set tuning mode to Manual

  • If you have multiple PID loops and the devices that are being controlled are similar, you can manually enter the PID values from a device that has already been tuned
    • This is found under the Advanced Settings section in the configuration folder for your technology object
  • Have a way to shut down the heat device if necessary, in case of a malfunction. In such a case, a heat switch button (externally wired or on the HMI) to enable the heat device(s). This way if the PID loop goes awry, you won’t run the risk of melting a part or burning up a heating element

By following these simple steps will save you time and prevent any headaches in setting up your PID loop to control your temperature device.