Mechanical vs. electronic pressure switches: Functionality

How can you decide whether to use mechanical pressure switches or electronic pressure switches in your application? Each kind of pressure switch has individual advantages, but additionally its limitations. The primary differences in functionality between mechanical and electronic pressure switches are the way the applied pressure is used to operate the switch, the kind of switch technology, and the way the switch point could be adjusted.
Functionality of mechanical pressure switches
A mechanical pressure switch converts the pressure of a fluid 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 time the switch is actuated, a mechanical pressure switch sends an electrical switching signal, but does not need a voltage supply.
Ordinarily, mechanical pressure switches are simple devices that are either created for cost-effective applications or optimised for long-term use, based on how usually the switching signal must 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 high application rate (frequent switching changes e.g. in process control). The hysteresis is normally not adjustable, thus the reset point for switching can’t be configured and is preset by factory setup.
Mechanical pressure switches are often used to switch high currents, such as pumps and drives. However, mechanical contacts frequently have problems switching the very low voltages in PLCs and modern electronics, unless expensive, gold-plated switch contacts are used.
Functionality of electronic pressure switches
An electronic pressure switch generates electronic switching signals and, frequently, also yet another, analogue output signal proportional to the pressure. They’re either programmed at the factory to the desired switch points or they include a programming interface with integrated display and buttons.
Electronic pressure switches have integrated, programmable logic. This permits 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 many more functions could be programmed in modern electronic pressure switches.
Useless of an electric pressure switch also offers a continuous pressure indication and shows whether the switch outputs are active or not. Last but not least, modern technologies, such as the usage of IO-Link, enable programming remotely via signal cables.
Note
More info 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

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