Problem of negative values displayed on the gauge pressure meter
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The company has a Yokogawa gauge for absolute pressure, with a range of 0–100 MBAR. After it was installed, it showed -5 MBAR. Normally, an absolute pressure gauge should not display a negative value; what could be the reason? Is the zero point of the gauge incorrect, or is the vacuuming process too intense?
Is it a 4–20mA signal? A negative value is displayed when there is no current signal (0mA); please check the current signal.........
It outputs 4-20MA; if there is no current signal, it doesn’t mean the circuit is broken – so how can a negative value be displayed?
Generally, in the absence of a current signal, that is, 0 mA, the gauge displays a negative value. The 4~20mA signal starts at 4mA rather than 0mA in order to facilitate fault detection, such as open circuits........
The key point is that the on-site gauge also shows -5 mbar, which is consistent with the control room reading
It’s clearly gauge pressure, so how did it turn into absolute pressure? Does it display 0 at atmospheric pressure (when the gauge is not installed)?
There’s something wrong with your question – 0-100 Mbar is equivalent to a range of 0-10,000 MPa. Do sensors with such a large range even exist? It also shows -5Mbar, -500Mpa – are such pressures possible? The two of them are still arguing about the 4-20mA issue. . . I'm drunk too
mbar millibar; otherwise there’s really a problem with the pressure
:Case doesn’t matter for L; it’s deadly
Well, the unit is millibar; it ranges from 0 to 100 millibar. When 475 is used, the current value displayed is 3.22 MA. The pressure is -4.8 mbar. What I mainly want to ask is: why does the gauge show a negative value? Is it zero-point drift, or is this indeed the negative absolute pressure value in the actual measurement?
It’s the Yokogawa EJA310A gauge for absolute pressure, which shows an out-of-range reading at atmospheric pressure