How do you decide whether to utilize mechanical pressure switches or electronic pressure switches in the application? Each type of pressure switch has individual advantages, but also its limitations. The primary differences in functionality between mechanical and electronic pressure switches will be the way the applied pressure can be used to use the switch, the type 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 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 time the switch is actuated, a mechanical pressure switch sends a power switching signal, but will not need a voltage supply.
Ordinarily, mechanical pressure switches are simple devices which are either designed for cost-effective applications or optimised for long-term use, depending on how often 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 cannot be configured and is preset by factory setup.
Mechanical pressure switches can be 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 employed.
Functionality of electronic pressure switches
An electronic pressure switch generates electronic switching signals and, frequently, also an additional, analogue output signal proportional to the pressure. They’re either programmed at the factory to the required switch points or they feature a programming interface with integrated display and buttons.
Electronic pressure switches 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 provides a continuous pressure indication and shows if the switch outputs are active or not. Finally, modern technologies, such as the usage 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?
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