OT: Bench Testing Rig for Learning PID (Probably PI)Control

[Dean]

My associate and I have a couple projects in the pipeline where the use of a control loop may be the best option for some temperature control. Neither of us know much more than setting up a few process controllers and pressing the auto-tune button. We have access to a BRX, and want to setup some kind of bench rig, that we can use to get more familiar with the idea from the standpoint of using the Do-More engine to do it. Most of what we will be doing is electric heater control, so staying close to that would be best I guess. I was thinking about cobbling together something using a hot plate, a beaker of silicone oil, and an RTD, but I'm open to ideas. What do training schools use to teach this?

[BobO]

My associate and I have a couple projects in the pipeline where the use of a control loop may be the best option for some temperature control. Neither of us know much more than setting up a few process controllers and pressing the auto-tune button. We have access to a BRX, and want to setup some kind of bench rig, that we can use to get more familiar with the idea from the standpoint of using the Do-More engine to do it. Most of what we will be doing is electric heater control, so staying close to that would be best I guess. I was thinking about cobbling together something using a hot plate, a beaker of silicone oil, and an RTD, but I'm open to ideas. What do training schools use to teach this?

That sounds like a great idea! If you use a solid state device to drive the power you can use TIMEPROP to control the output, for much more accurate control.

But the easiest thing to play with is the process simulator built into DMSim. It lets you set process time constant, dead time, and even inject noise into the process. We've also done a couple of mechanical tests as well, but both were much faster processes than your proposal: 1) a T/C tacked to the side of a low wattage incandescent bulb, and 2) a pair of PC muffin fans, one driving and one configured as a generator driving a small load.

[Dean]

Yeah, I've been playing around with the Simulator PI example, but I think we could foster our understanding better if we could see and manipulate a "real" process.

[BobO]

Yeah, I've been playing around with the Simulator PI example, but I think we could foster our understanding better if we could see and manipulate a "real" process.

Nothing quite like doing it for real. Let us know how it goes!