While choosing the pressure sensor for your design, you have to look for some critical parameters, that are very important. Based on these parameters, you have to choose the available sensors. Of course, you have to look through the economical angle also.
These are the main parameters to look for –
Accuracy – First and foremost parameter is accuracy. What kind of accuracy you are looking for? Is your pressure very dynamic? Changing very fast? Or is the change slow? What is the rate of change? Do you have to continuously monitor the pressure and record the data or you have to measure it periodically? Based on your process, you have to decide, what kind of accuracy you are looking for. This will decide the type of sensors. Sensors are available with 0.5% accuracy to 0.1%, 0.25% and 0.05% accuracy. As the accuracy increases so as the prices.
Output – After you decide the accuracy, you have to look for the kind of output. These sensors come with Voltage and current output.
Sensors with voltage output, are generally used,where the sensors and measuring instrument or Data Acquisition system, both are near to each other. These sensors give out put in mV (millivolt-1000th of a volt) in the range of around 0 – 30 or 100 mv. Some sensors also have internal amplifier that offer output in the range of 0-5V or 0-10V. These kinds of sensors generally use strain gauges. The sensors with inbuilt amplifiers also provide internal zero and span adjustment facility. Though, because of these internal amplifiers, the frequency response is slow.
Sensors with current output are generally used when the distance between sensors and the measuring instrument or Data Acquisition system is more, like in big plants. As the output is in current form, they have high noise immunity. They also provide zero and span adjustment besides offering high frequency response.
Environment – The location of the sensors. This criteria is also very important in deciding the type of sensor. The operating environment will decide the mechanical structure of the sensor. If the sensor has to be used in harsh environment, it will have extra protection and because of these, it will cost more. While the sensors,which are used indoors,cost less.
Fitting – This is also an important factor. How you are going to fit the sensor? Does the sensor come with easy fitting couplings? Or you have to make a spatial mechanical arrangement for fitting? You have to consider all these factors before considering a particular type of pressure sensor which will fit into your design.