Proportional Output Thermostat
Proportional Output Thermostat
(OP)
Hey guys,
This is my first time here, this appears to be the largest assembly of engineering brain-power on the web LOL. Hope you can help with this one.
I'm trying to find a "stand-alone" thermostat controller with the following features, to control a very large recirculator fan:
*NEMA 1 or IP 10
*120VAC powered
*an operating range of 10~40 deg C
*4~20mA or 0-10VDC output
*programmable
I'm wanting to vary the speed of a VFD based on a change of temperature between 60 and 80 degrees F, and can't seem to find anything with a proportional band greater than 2 or 3 degrees F. I would like to stay away from RTDs for simplicity's sake... was wondering if anyone knew of a manufacturer or distributor of such a beast.
Thanks for any help,
This is my first time here, this appears to be the largest assembly of engineering brain-power on the web LOL. Hope you can help with this one.
I'm trying to find a "stand-alone" thermostat controller with the following features, to control a very large recirculator fan:
*NEMA 1 or IP 10
*120VAC powered
*an operating range of 10~40 deg C
*4~20mA or 0-10VDC output
*programmable
I'm wanting to vary the speed of a VFD based on a change of temperature between 60 and 80 degrees F, and can't seem to find anything with a proportional band greater than 2 or 3 degrees F. I would like to stay away from RTDs for simplicity's sake... was wondering if anyone knew of a manufacturer or distributor of such a beast.
Thanks for any help,





RE: Proportional Output Thermostat
A little confusion here.. You are talking VFD at the same time as 120Vac... Not real common.
Actual motor HP and power type 3ph voltage?
Environment?
Controlled to temp? (operating range = ambiguous)
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Proportional Output Thermostat
RE: Proportional Output Thermostat
If you don't want to use an RTD or a T/C, you can use a temperature transmitter. I would mount the controller next to the VFD and mount the temperature sensor remotely.
h
yours
RE: Proportional Output Thermostat
BK
RE: Proportional Output Thermostat
RE: Proportional Output Thermostat
Look for a function in the VFD programming called PID control or even just PI control. Most will allow you to adjust the setpoint either through the keypad or through a simple external potentiometer. If this is the only control loop associated with this system, that would be the way to go IMHO. Do you already have the VFD? If so, what brand/model and we can tell you if it can do this without an external controller.
If you need to have a display that lets you know what the set point is, many VFDs can do that also, but in that case it may be easier to just use the controller shown by waross.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Proportional Output Thermostat
This thing has to be as close to plug-n-play as I can get it for the installation people; I have little faith in "lectricians". I hate to think about a good ol' boy trying to scale current loops, but wish me luck!! Hopefully, the instructions I write will be good ones.. lol.
Thanks again for the input,
~M
RE: Proportional Output Thermostat
http://www.controlres.com/wispii.htm
RE: Proportional Output Thermostat
respectfully
RE: Proportional Output Thermostat
RE: Proportional Output Thermostat
That would be great! Again, thanks guys for all your input!