Looking for multichannel PID controller IC

Look at 'Microchips' website. They have many development boards too. If you do not find exactly what you want, send me some private email. We do lots of embedded control development for other companies....

James

Or Atmel, or Silicon Labs, or Infineon, or Philips, or, or, or.

The cheapest way for a hobbyist or a product is to use a microcontroller, an ADC, and a driver with some PID software. Are you doing a one-off, a hobby project, or is this for a product?

See the various articles on my website for guidance on implementing your PID controllers once you've found your processor, or contact me.

Thanks for info, but would like a dedicated PID controller IC like those dedicated motion controller IC's. This would be for a medium-volume embedded SBC-type product.

I am familiar with the motion controller IC's from some time ago, but haven't sufficiently kept up with the IC data book barrage lately to know if there are similar offerings for a generic PID controller IC.

tia!

Look at the chips from Performance Motion Devices:

snip

I don't know of any off the shelf pid controller solutions. If there were I doubt I'd get as much consulting business as I do.

Doing a pid controller in a micro is pretty simple. I've done several variations on pid temperature controllers. Typically the cycle time is pretty slow, so doing a controller in C, using floating point math is usually fast enough.

I've a bit of experience with Microchip PICs in these sorts of applications, and development has been pretty easy (though about any decent microcontroller would do). Microchip even has some high end 18F series parts with 16 analog inputs (18F8720. etc.). You could add an analog mux to other smaller microcontrollers.

If the thought of writing code from scratch for a microcontroller fills you with dread, consider hiring somebody to do that part for you. If you need more than 10 of these things, you should be able to hire someone to do the initial PID control loop design for you, and still come in under what it would cost you to buy a commercial product.

mark

Really a microcontroller is about as close to an off-the-shelf PID controller as you could get -- particularly for a temperature controller where the speeds will be fairly slow. I doubt that there is a dedicated "PID" controller chip that you could design that would be able to do anything you couldn't do cheaper and better with a microprocessor and some software.

In fact, for dedicated motor control the market seems to be swinging in the direction of small DSP chips with software, as well.

Do you have issues with software (medical, safety critical, etc) ?

Sorry for plugging my own company but you asked. The CLS or MLS family from Watlow would be one method;

I'm in R&D so I don't know pricing but you can get that pretty easily on the phone. If you are only looking for one unit I see these on Ebay periodically. Omega probably has something similar.

If this is OEM stuff we may have some custom off the shelf solutions for you.

Again I apologize for doing a commercial.

Bill Schuh Watlow

I generally agree with others, in that I'm not aware of some IC solution to this. In the past, I've just developed appropriate code. But I can suggest some questions and considerations.

There are several factors which can be very important for PID control loops. One is simply keeping your "observation" to "control" timing both short and repeatable. There is almost nothing worse than having a long lag time between making a measurement and outputting a control, where "long" is a time related to response of your system. And having variability in that timing only makes it very much harder to find good PID parameters that will work, consistently.

I like to imagine having a long, thin, all-too-flexible bamboo pole and standing on the ground trying to poke it through a tiny hole in a bird house from some distance. The length of my pole is the time delay from observation to control output and varying that time is like having a pole that is constantly changing in length. If you want to make this easy, you want a short pole and one that doesn't change it's length. If you want to make it really hard, get a long pole and/or make it vary a lot, too.

Tighten up your timing as much as you can and work on the variability, too. Both are important for clean PID control and it will save anguish in the end. (That is, if you are forced to write this yourself or you get someone else to do it for you.)

...

In general, by the way, how fast is your RTD and the system response to closed loop control? Why are you using an RTD? Is it because you have a much wider temperature range than a thermistor, for example, could be used? (RTDs generally are lower sensitivity, but better linearity and operable over wider temp ranges.)

Jon