How do you decide whether to utilize mechanical pressure switches or electronic pressure switches in your application? Each type of pressure switch has individual advantages, but also its limitations. The main differences in functionality between mechanical and electronic pressure switches will be the way the applied pressure can be used to operate the switch, the kind of switch technology, and how the switch point can be adjusted.
Functionality of mechanical pressure switches
A mechanical pressure switch converts the pressure of a fluid right into a mechanical movement that actuates the mechanical switch contact in the pressure switch. The switch has the preset or an individually, mechanically adjustable switch point. Each and every time the switch is actuated, a mechanical pressure switch sends a power switching signal, but will not require a voltage supply.
Ordinarily, mechanical pressure switches are simple devices that are either designed for cost-effective applications or optimised for long-term use, depending on how usually the switching signal should be transmitted. The switches are thus designed either for a minimal application rate (very few switching cycles e.g. in safety applications) or for a higher application rate (frequent switching changes e.g. in process control). The hysteresis is usually not adjustable, thus the reset point for switching cannot be configured and is preset by factory setup.
Mechanical pressure switches are often used to switch high currents, such as for example pumps and drives. However, mechanical contacts frequently have problems switching the low voltages in PLCs and modern electronics, unless expensive, gold-plated switch contacts are used.
Functionality of electronic pressure switches
An electric pressure switch generates electronic switching signals and, frequently, also yet another, analogue output signal proportional to the pressure. They are either programmed at the factory to the desired switch points or they include a programming interface with integrated display and buttons.
Pleased have integrated, programmable logic. This enables the switch points and the output signal to be adapted to the application-specific needs. Delay time, switch point, reset switch point, hysteresis or window function, normally closed or normally open, and more functions could be programmed in modern electronic pressure switches.
The neighborhood display of an electric pressure switch also offers a continuous pressure indication and shows if the switch outputs are active or not. Lastly, modern technologies, like the use of IO-Link, enable programming remotely via signal cables.
Note
Further information on mechanical pressure switches and electronic pressure switches are available on the WIKA website.
Also read our articles
Mechanical vs electronic pressure switches: Application areas
Mechanical pressure switches: How does one set the switch point?
Pressure switches in booster pumps