I don't doubt your involvement. I was concerned that your new interjections would confuse the general readers of this board. Not that we're idiots but few lab technicians gain there info from this site.
Quote:
|
At this end I am referring to types of controllers which would give the end user the best kind of temperature accuracy, which is neither the SSR or the PID, but one that produces a current output such as 40 millivolt or 4-20ma.
|
As far as current output, again you are comparing apples to oranges. My PID controllers
DO output current in the range you noted. One port is used to drive the solid state relays and the other port can be used to drive P10, P100 or Cu50 sensors. I choose to use the type K sensors because of the higher range available. (Besides, it came free with the PID.) I think the accuracy of 0.2% for a PID controller is good enough for most of the applications covered on this board and then some. For the range used in powder coating, that amounts to less than one degree (0.8 degrees F). And you can get that accuracy for $50 or less!
If you use a higher range of temps as I do on one oven, the sensor coefficient can be changed to gain +/- one degree accuracy at 1700*F. I figure that's close enough for my stuff. A PID temperature controller is far more than just a switch as you imply. It's a full blown computer that teaches itself and acts based on parameters supplied by the user and/or from what it learned. After re-reading your comments, I'm beginning to doubt whether you even know what a PID temperature controller is or how it works. I let the SSR slide.
But of course, I may just be an idiot.