We all know that pressure is an indeed important factor in every fluid-power circuit. Pressure transducers or pressure calibration systems can interface the factor with the control systems. When pressure transducers are connected to an electrical source and then when they are exposed to a pressure source, this will produce an electric signal in the form of current, voltage or frequency, which is directly proportional to the pressure. Most of the pressure calibrating systems are designed o produce an output which is equivalent to the applied pressure and most important among all the other variables is temperature. Majority of the outputs are mV, V, mA and sometimes it is even frequency.
What are pressure transducers or made up of?
Yes, by now you must be wondering about the technology that works behind the pressure calibrating systems. They’re nothing but mechanical structures that are made from more than one material. Due to this reason, they not only respond to changes in pressure but they also respond to changes in temperature too. Such changes can affect both the full scale and the zero output of the transducer, irrespective of the type. There are some extreme temperature fluctuations that might change the output signal of a transducer even when the pressure remains static.
There are many different characteristics like hysteresis, linearity and repeatability that help to determine the accuracy of the measurement of the pressure calibration system. Overall, remember that the best pressure calibration system for one particular application isn’t always the best one for another application. In fact a transducer with performance that can be rated second-best might be considered as the best choice for another application which is considerably lower. When you’re operating such machines, you need to keep such vital things in mind.
Important terminology you need to know of
Here are some vital definitions that are used to put a quantitative value on the performance of a transducer.
Range: Range refers to the minimum through maximum pressures that can be approximately measured through a transducer. Usually, they’re selected so that the operating pressure of the system is 50-60% of the maximum rated pressure of the transducer.
Over-range capability: This is the maximum pressure or magnitude that can be exerted to a transducer without causing a minimum change in the performance of the machine.
FSO or Full Scale Output: This refers to the variation of the output signal as the transducer performs over the calculated range from the minimum to maximum pressure recorded at a particular temperature. The tolerance and temperature are usually given.
Burst pressure: Burst pressure indicates the fluid pressure at which mechanical failure from the transducer might be expected. Don’t confuse between burst pressure with over-range capability.
Hence, if you’re wondering about how the technology behind pressure calibration systems works, you may take into account the above mentioned information. It is only when you know about the system that you can start using it on your own.