phantomcow2
07-21-08, 03:50 PM
Does anybody here have any experience with these? I acquire one today to climate control my bedroom, and am having some difficulty configuring it.
Foo - Watlow temperature controllers
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phantomcow2
07-21-08, 06:14 PM
This is a PID output, but I want it to control a simple on/off operation of a relay.
vote robotlican
07-21-08, 06:35 PM
my aunt works for them, but I've never actually seen one.
/useless
/useless
skinnyone
07-21-08, 07:23 PM
This is a PID output, but I want it to control a simple on/off operation of a relay.
PID refers to the compensation in control loop Proportional, Integral, Differential. (2 zero's and pole from the compensation network)
I worked with one back in the day for a TEC but I think it had a PWM output.. What kind of output does it have analog/dig/pwm? or the model number would be great as well.
I would probably use it with hysteresis, program it to a few degrees differential. Experiment a bit with the amount of hysteresis and you could prob get a good system out of it.
PID refers to the compensation in control loop Proportional, Integral, Differential. (2 zero's and pole from the compensation network)
I worked with one back in the day for a TEC but I think it had a PWM output.. What kind of output does it have analog/dig/pwm? or the model number would be great as well.
I would probably use it with hysteresis, program it to a few degrees differential. Experiment a bit with the amount of hysteresis and you could prob get a good system out of it.
phantomcow2
07-21-08, 07:36 PM
This is a Watlot 965 series. http://www.watlow.com/literature/prodtechinfo/files/controllers/series_965_eng_c.pdf
skinnyone
07-21-08, 08:13 PM
This is a Watlot 965 series. http://www.watlow.com/literature/prodtechinfo/files/controllers/series_965_eng_c.pdf
I didnt read it much, (slow ass laptop and my wireless access is bad) but here is something that should get you started.
On page 4
"Setting the proportional band to zero makes the Series 965 a simple on/off control with switching
differential selectable under the HSC parameter."
This means that when you program the coefficients, set the prop band to zero and select your hysteresis(HSC parameter) to what ever temperature differential to whatever you would like. Experiment with it so that the turn on and turn off periods are reasonable. Too small of a differential and you oscillate (and be power inefficient as you will start and switch off a compressor too often). Too large might mean that you might feel yourself going between sweaty to cold.
Let me know if this makes sense, else I can have a look tomorrow and give you a detailed overview.
I didnt read it much, (slow ass laptop and my wireless access is bad) but here is something that should get you started.
On page 4
"Setting the proportional band to zero makes the Series 965 a simple on/off control with switching
differential selectable under the HSC parameter."
This means that when you program the coefficients, set the prop band to zero and select your hysteresis(HSC parameter) to what ever temperature differential to whatever you would like. Experiment with it so that the turn on and turn off periods are reasonable. Too small of a differential and you oscillate (and be power inefficient as you will start and switch off a compressor too often). Too large might mean that you might feel yourself going between sweaty to cold.
Let me know if this makes sense, else I can have a look tomorrow and give you a detailed overview.
phantomcow2
07-21-08, 08:26 PM
Okay, I did set the PB to 0. I'll set the HSC now and report back. THe problem i am having is configuring this thing's internal relay. Actually, since this a mechanical relay, I'd prefer it drive an external solid state relay. Thanks; I knew BF would come through!
skinnyone
07-22-08, 07:47 AM
I dont have too much experience with AC power distribution but id figure you are better off using the watlow as a control for a relay given that surge currents can be 1.5 to 2x rated current for compressors, motors and the like. If you are concerned about that, a condensor may help.
By the way you are you going to attach a separate temperature sensor to the watlow sensor and set the AC to the lowest set point possible?
By the way you are you going to attach a separate temperature sensor to the watlow sensor and set the AC to the lowest set point possible?
phantomcow2
07-22-08, 12:32 PM
You've described exactly my plan: Use the Watlow as a control for a solid-state relay, which sees the current drawn by my fan. I have plenty of thermocouple wire, which I have attached to the Watlow and confirmed it is working. I'm not sure what you mean by setting the AC to the lowest setpoint possible.
Also, while it would certainly be overkill and impractical, I would love to use PID output to control the fan. The problem is that I have no idea how!
Also, while it would certainly be overkill and impractical, I would love to use PID output to control the fan. The problem is that I have no idea how!