Important considerations arise when selecting a differential pressure sensor. These include the highest level of pressure and the range of differential pressures that the sensor can take. Firstly, this particular device, which may also be a differential pressure transmitter, is tasked with measuring the difference between two or more pressures. The value is often used as input to a process feedback system to ensure that the process runs within the desired range of parameters. An important consideration when choosing this type of device is to avoid confusion about pressure ratings. Because the measured pressure is the difference between two values, this is relatively small compared to gauge pressure or absolute pressure. Therefore, there is a danger of exposing the product to too much pressure if the expected differential pressure is used as the basis for determining the ratings of the differential pressure sensor to be purchased.
There is also a possibility that the pressure that would be exerted on the detection diaphragm of the differential pressure sensor is not uniform throughout the length of this device. Uneven voltage distribution can result in modification of the analog output signal if the mechanical configuration of the sensor is not designed to handle this type of voltage. The skewed pressure distribution is likely to compensate for the detection diaphragm to deviate from its previous location. The uneven distribution of forces in the detection diaphragm can actually affect the entire sensor because this particular part is connected to various other components.
Some of the sensors that could be affected by uneven pressure are those that have thin and brittle insulation membranes on both sides of the detection diaphragm. The potential problem is that the volume of the oil inside the transducer can increase or decrease in size depending on the temperature. To avoid this problem, the design of the insulation membranes could be adjusted in such a way that the thermal expansion or contraction of the oil does not affect the detection diaphragm too much. Meanwhile, another way to avoid the above problem is to have dry transducers, like Keller pressure sensors. Because the temperature has less effect on the solids, these sensors are more stable, although they are not completely free from changes caused by temperature. https://megatron.co.il/
There are other innovative ways to avoid the above mentioned errors in the differential pressure sensor. Two absolute pressure sensors can be used for those situations where the differential pressure is much higher than the common values. Some manufacturers have placed mechanical stops for the diaphragms to avoid uneven loading of different ends of the device. For those situations where accuracy is of the utmost importance, you may need to carefully examine the product data sheet for thermal zero errors. Sometimes precision is only provided for ambient temperature. Therefore, you will need to look elsewhere in the data sheet for the accuracy of other temperatures. And when there is a substantial variation in line pressure, it is advisable to use a DP transmitter with an absolute pressure sensor that compensates for changes in line pressure.
This is done by inserting a synchronization bit string into the telemetry stream on a regular basis, usually at the beginning or end of each repeating cycle.