A Pressure switch is a commonly used instrument in the process industry. Like many instruments used in science, they need to be calibrated to ensure their accuracy and reliability. The wrong calibration can cause errors in results or damages the equipment. This can cost a laboratory or industry a significant amount of money.
A pressure switch is an instrument that measures pressure and has an electrical switch function programmed to operate at a certain pressure.
It can be set so that when there is no pressure connected, the switch is closed. When pressure increases, the switch opens.
Normally open switches have the switch terminal open when no pressure is connected. When enough pressure is applied, the switch closes. Normally closed switches are closed when no pressure is connected and when enough pressure is applied it opens. The determining factor in which one is best for your use is dependent on what kind of circuit you want to drive with the switch.
A dry switch has the connections being open or closed, so it is working like a mechanical switch. A wet switch has two different voltage values representing the two output states.
The output of an electrical wet switch can be a voltage signal with two levels, a current signal, or an open collector type signal.
Safety switches are used in the safety instrument systems, and they have specific safety classifications. The calibrations of these are regulated.
These switches stay static most of the time without ever functioning. They don’t toggle open and closed in normal usage; they are waiting if the safety alarm level is met then they operate. Because these switches do not operate a ton, there is the risk that they will not work when needed.
When calibrating do not exercise these safety switches prior to calibration, instead of capture the very first point when the switch operates. It may be that the first operation that requires more pressure than the operations after a few exercises. Regular switches are typically exercised a few times before calibration. In a safety switch, the operation point is critical.
When selecting a switch type, the state should be considered so that should the power supply fail, or a cable becomes loose, the switch status should remain safe. In the case of a safety switch, it should be configured so that in case a cable comes loose, the alarm goes on. It is designed to be fail-safe.
There are a few steps when getting ready to calibrate switches.
SRP control systems ltd offers solutions and help for pressure switch calibration and many other types of instrument calibration. Contact us today and let us make your business run as smoothly as possible.