I've searched the web extensively and have learned a lot about PID control in general. However, I haven't been able to find specific details about a couple of key aspects of my particular app - controlling water temp with an electric heating element. How to characterize the "plant?" I plan on giving it step commands to go from one temp to the next for periods of time. I envision taking some open-loop measurments of heater voltage vs. thermistor voltage. How should this data be used to form a model of the system? What about lag time? Do I need to include some kind of filter? I'm thinking about using an A/D and D/A for sensor input/controller output to/from parallel port. The algorithm should be pretty simple but what's the best way to implement (from a high level point of view)? Thanks to anyone who can help. Regards, JJ
- posted
20 years ago