Research Article Open Access

Using PLC for Custom-design of a PID/PWM Program to Control a Heater Temperature

Mohammad A.K. Alia


This is a practical approach to control a continuous-time process variable (temperature) using a discrete controller (PLC) and a custom-designed software control algorithm and hardware interface, in a closed-loop system. Unlike the conventionally known technique of transforming a digital control action into a proportional analogue one by a D/A converter followed by power amplifier, the control action was formed internally by the PLC as a PID/PWM signal, which was used to trigger the power stage. This approach helped reducing the error due D/A conversion, maximized utilization of the PLC and reduced total cost. The control system is realized by utilizing the heater of the training board (RGT1), manufactured by DL-lorenzo Company and it simulates an analogue heating control system. The PLC is Siemens Simatic S7-214 model. An experimental result has shown that the control algorithm functions perfectly.

American Journal of Applied Sciences
Volume 4 No. 5, 2007, 307-316


Submitted On: 22 January 2007 Published On: 31 May 2007

How to Cite: Alia, M. A. (2007). Using PLC for Custom-design of a PID/PWM Program to Control a Heater Temperature. American Journal of Applied Sciences, 4(5), 307-316.

  • 4 Citations



  • PLC
  • PID software program
  • PWM
  • PLC
  • analogue input digital output
  • interface board