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MoreGranularity
- 6th January 2013, 18:30
I want to control the temperature of a small pressure sensor in order to increase its accuracy. This silicon differential pressure sensor is about 1" x 0.75" x 0.2" and has very little mass. It is mounted vertically on 4 pins in a pcb. The pressure calibration drift with varying ambient temperature is what I am trying to reduce.

Normally the battery operated test instrument with this pcb/sensor is often moved around and exposed to indoor and outdoor temperatures. I would like to keep the pressure sensor temperature fixed within 1 degree C or better over an ambient range of about 5 C to 45 C. There is not much room in the instrument enclosure but I could probably put a little foam insulation around the sensor.

I am considering PID control with a DS1820 temperature sensor and 18f2520.
Perhaps a one channel, battery operated version of
http://www.picbasic.co.uk/forum/showthread.php?t=12712

Does anyone have any suggestions for how to do temperature control on such a small item?

TIA

aratti
- 6th January 2013, 18:52
If the ambient temperature can vary from 5 to 45 celsius than you should warm up your sensor to 50 celsius, easy to achìeve but the main problem is the current requirement to keep the sensor at 50 celsius with a battery operated device.

Cheers

Al.

MoreGranularity
- 7th January 2013, 20:45
Yes, my calculations suggest the current is too much for battery operation. So much for plan A.

On to Plan B: I am going to see if the pressure sensor temperature variations can be removed mathematically by attaching a ds1820 temperature sensor to it.