monitoring pressure room

Are you sure you need such a low range??

¼" H₂O is sod all!! There are manufacturers that could supply one , but at extortionate prices and they would be extremely delicate instruments!!

For normal clean room pressure monitoring a range of a few inches or more is used...

If a door was to be closed that would make your ¼" range transducer 'hit its stops' or over range!!

John.

Yes most of the pressure monitoring are at -0.2 to 0.2 inWc so it will be o.k. and the setpoint it,s 0.16

Try Furness Controls they do extra low pressure sensors, but be warned the prices start at £200 to 300 each...

RDP do some cpacative sensors for very low range and they aren't so expensive +/- 10 mBars.

Bur mounting them is another problem, vibration will give totally misleading results etc...

If you can't find what you're looking for at those prices contact me, I've done a fair amount of medical pressure sensing at low ranges...

John.

thanks for your help, But I try to fine something like the setra srpm at low cost.

what I want to know is how will you adjust it every 15 minutes for atmoshperic pressure. You want .25 in vacuum and .25 in positive pressure. Good luck with that one.

vicini, it would be used in differential mode, so ambient air pressure is the same at both ports.

Try Moore (usual disclaimer).

Good luck on finding something that is actually accurate at that level. They might sell you something that will read that low but I would definitely doubt the accuracy.

I was heavily involved in developing HVAC sensors for 11 years with Kavlico Corp and can tell you that it will measure 0.25" of water but the problem lies in the test equipment used in calibrating them to that level. We utilized Mensor equipment (with 1" of water range) for calibrating our low pressure sensors and we sold units at +/- 0.5" of water, but I can tell you from experience that at 0.25" of water there was no variation in the reading from the Mensor, which is a sign that the sensor is not going to be very accurate at that particular point.

I would recommend Kavlico since they are probably the world leader in HVAC sensors but I know they don't offer 4 to 20ma transmitters for HVAC applications. When I left 2 years ago we were developing a frequency output to eliminate the customers need for conversion. The HVAC industry tends to use frequency monitoring as opposed to current.

a rosemount gold series would come closest.