Zeroing issue of differential pressure transmitters.
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There is a differential pressure transmitter used to measure the liquid level in a sealed container, with a measurement range of –104.22 to 4.75. Now that the manhole is open and the pressure is at atmospheric level, it is necessary to adjust the zero point. Should the zero point be adjusted directly, or should the measurement range first be set to 0–108.97 before adjusting the zero point?
The upper and lower ends are exposed to the atmosphere; use 475 for automatic migration
If the linearity is good, migration will work
I’ve encountered this situation before as well. There are two ways to perform zero calibration: one is to force the device to the position corresponding to 4m, and the other is to directly force zero pressure. I once had to deal with a domestically produced device that had 100% negative drift; its zero calibration setting corresponded to the full scale, which was quite problematic
So this is a troubling issue; if zeroing is done according to the specifications, is it necessary to zero again after migration?
I think your range is adjusted based on the tank being used, which means this range should be correct; just zero it out using 475!
The measurement range is from –104.22 to 4.75, with atmospheric pressure corresponding to a point within this range; the output is between 4 and 20 mA. Is zero adjustment performed under these conditions? The correct approach is to enter the standard signal of –104.22 to 4.75 for calibration; no adjustments should be made otherwise. Enter –104.22 to set the zero point, and enter 4.75 to set the range...........