Foxboro 13A pneumatic transmitter calibration

[avoilers]

Probably would have been easier and more accurate to have used a Wallace and tiernan for the calibration eh?

[rpm750]

Yeah missed the fact that the PV is 0 - 34" WC and the output span of the transmitter is 3 - 15psi.

[rpm750]

Doesn't he mean 34 ft of WC, 15 psi is equal to 34 ft of WC.

[BTCInstrumentation]

@rpm750 Actually, no. The transmitter has been calibrated such that applying a fluid pressure of 0 inches WC produces a 3 PSI air pressure output, and applying a fluid pressure of 34 inches WC produces a 15 PSI air pressure output. That's the beauty of a calibrate-able transmitter: you can span it for an arbitrary pressure range within certain limits.

[nasnikos]

By "LRV" you mean the air pressure signal on Hi section, right?

I want to ask smth else:

What's the right method on calibrating? The Static calibration (in the lab, zero adjustment without any pressure)

or the dynamic calibration (on the flow line, zero adjustment by opening the bypass valve) ?

Thanks

[Rooksie11]

ahh ok, i am a student at NAIT in edmonton alberta, and they teach us to drop to LRV whenever adjusting span, thanks for the great videos, they are very useful for students

[Rooksie11]

dont you have to drop pressure to LRV when adjusting span?

[BTCInstrumentation]

@Rooksie11 Actually, you don't have to. It does help sometimes, however, to shut off the air pressure to relieve force on the range wheel. This makes the range wheel easier to turn.

[bo3assah]

thanks my friend nice explaination

i appreciate your work

[dufmip]

thanks a lot, a lot.