A delta P transmitter is a delta P transmitter whether both legs are filled with air, vapor or some type of liquid (A.K.A. dry leg vs. wet leg). After all, it is only measuring differential.
That said, calibrating a DP with both legs at atmosphere (or the lo-side at atmosphere and the hi-side...
Not all calibration procedures tell you exactly what to do step by step. In fact, many utilize "skill of craft" in order to perform calibrations of instruments on non-safety related systems. As such, it isn't necessarily a matter of being "inept" but possibly "unfamiliar" in this instance.
If I...
With a range in inches of water (in/h20) it should be possible but I cannot say for sure.
I can see a possible issue where a technician accustomed to a 0-100 (in/h20) /4-20madc output transmitter would be unsure if a transmitter calibrated for 0-100 (in/h20)/ 20-4 mAdc output would require a...
For the sake of discussion, let's assume that it is an older analogue (electronic and not pneumatic) transmitter that is now due for a routine calibration check.
After a nine point check, the instrument needs adjustment. With both hi-side and lo-side legs equalized (zero delta p), the...
This is a dp level transmitter for indication only. No controlling action in this scenario. Additionally, the swapping of the sense lines wouldn't be permitted under configuration control.
Therefore, at some point, a future calibration would be required and adjustments to the zero and span...
A level transmitter (0-100 in/h20 = 4-20mAdc) is bench cal'ed and installed on a liquid tank. Later, the transmitter is essentially re-ranged whereby 0-100 in/h20 is now equal to 20-4 mAdc output. Given the inversion, would you now also invert your calibration use of the zero and span...
Thanks for the reply.
"Zero and span affect the input, not the output" That is certainly one way to describe the zero/span relationship.
Zero adds and subtracts while span multiplies and divides; Zero shifts the input/output curve along the "x" axis, while span changes the input/output slope...
It was in a scrap metal bin and couldn't be removed for "experimenting purposes" or I would have eagerly dissected it...................:) I'm sure that it was likely a very popular model in its day. I can't imagine the zero having enough turns on the pot to shift the zero to the opposite end of...
Recently, I ran across an old removed "dumb" Rosemount DP xmitter (didn't get the model number) with only a zero and span adjustment on the outside of the xmitter housing. I was wondering if this type of old transmitter allowed the entire range to be shifted via the zero adjust? In other words...
