# Temperature differential sensor



## user4818 (Jan 15, 2009)

This is entry # 1,034,457 into Marc's journal of esoteric projects. What on earth are you doing this time?


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## MDShunk (Jan 7, 2007)

Peter D said:


> This is entry # 1,034,457 into Marc's journal of esoteric projects. What on earth are you doing this time?


Slowing down a supply fan for the off seasons, when only a zone or two is calling, so that the building's doors don't blow open and the mag locks stand a chance of locking the doors. The other option is a barometric relief damper and a freeze stat, but that's sorta old-school.


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## MechanicalDVR (Dec 29, 2007)

Normally it's done with a pressure differential or building static pressure sensor.


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## MDShunk (Jan 7, 2007)

MechanicalDVR said:


> Normally it's done with a pressure differential or building static pressure sensor.


That would make more sense. Might as well measure the offending problem. Got any leads on some product?


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## Jlarson (Jun 28, 2009)

If you still want to go temp. sensor this might work:
http://www.omega.com/pptst/DP26.html
You can get it with 4-20 and/or digital output


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## John (Jan 22, 2007)

Use a PLC with 2 analog inputs and a single analog output module. Just run 2 type J or K thermocouples to the PLC and a analog output from the PLC to the VFD. a little programing and you are done.:thumbsup:
I run my attic fan this way and it works slicker than whale snot.

BTW October is national pajama month.:notworthy:

View attachment 1854


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## randomkiller (Sep 28, 2007)

We normally use a Johnson Controls P352PQ-1C sensor, not sure if you deal with Industrial Controls Inc or not but they should have these and a couple of generics in stock as well.


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