Transmitter negative drift
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The range of the transmitters used in our factory’s reactors is -101 to 101 KPa, but some transmitters have a range of 0 to 100 KPa. Does this result in out-of-range migration? Should the range after migration still fall within its specified limits? I’ve just started working with instruments and don’t know much about them; I hope those more experienced folks can offer some guidance.
It depends on the model of transmitter you are using; whether the range of that specific model includes -101 to 101 KPa. If it does include -101 to 101 KPa, then it’s possible to make the change, even though the transmitter’s normal range is 0 to 100 KPa
The range is the difference between the upper and lower measurement limits; for a transmitter with a measurement range of -101 to 101 KPa, the range is 202 kPa. The measurement range is from 0 to 100 KPa; the range of these transmitters is 100 kPa. Since the ranges differ by a factor of 2, they cannot be used interchangeably. However, it is possible to consult the manufacturer, as some transmitters have a wider range.
The range is not necessarily the maximum measurement range of the transmitter; for example, with the Rosemount 3051CD4A transmitter, we might use a range of 0-100 or even less, but the actual usable range of the transmitter is greater than 200. So you should check the transmitter’s measurement range – it may differ from the stated range, and this information is usually indicated on the transmitter’s nameplate
This is not negative transfer; it is due to an insufficient range. . .
The range of 0~100 KPA at the installation site is usually set by the manufacturer according to the customer’s requirements; this is unless the transmitter used on-site has a very narrow range. Nowadays, intelligent transmitters have relatively wide ranges, and 202 KPA poses no problem for ordinary transmitters. The key issue is measuring negative pressure, i.e., -100 KPA. If the transmitter cannot be used in environments with negative pressure, then it’s useless no matter what. Therefore, the model of the transmitter at the installation site is crucial – by checking the selection table, it’s possible to determine whether it can be used or not.
It depends on the range that the transmitter is capable of handling; generally, to measure negative pressure of -101 KPa, an absolute pressure transmitter needs to be used
For the Rosemount 3051T series of transmitters, the range is normally 0 --- XXXX, but under special circumstances the range can be changed to -XXX to +XXX. It can go down to -101, but this is only a theoretical value; in reality, no device is capable of achieving a pressure of -101. I’m not sure what kind of transmitter you have; I hope this can help you
Used in distillation; the vacuum achieved with a three-stage Roots pump can reach -0.1 MPa, and at a pressure of -101 to 101 KPa, the current value is 12 mA
Zero calibration is sufficient; the range should be adjustable
Please note here that the gauge pressure reviewer (with negative pressure) and the gauge pressure sensor are two different types of sensors, so they cannot be migrated. Shanghai Ligee 2880189604