How do you decide whether to use mechanical pressure switches or electronic pressure switches in the application? Each type of pressure switch has individual advantages, but additionally its limitations. The primary differences in functionality between mechanical and electronic pressure switches will be the way the applied pressure can be used to operate 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 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 an electrical 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, based on how often the switching signal should be transmitted. Funniest are thus designed either for a low application rate (hardly any switching cycles e.g. safely 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 can be used to switch high currents, such as for example pumps and drives. However, mechanical contacts often have problems switching the very 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, very often, also yet another, analogue output signal proportional to the pressure. They’re either programmed at the factory to the required switch points or they include 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 whether the switch outputs are active or not. Lastly, modern technologies, including the use of IO-Link, enable programming remotely via signal cables.
Note
More info on mechanical pressure switches and electronic pressure switches can be found on the WIKA website.
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Mechanical pressure switches: So how exactly does one set the switch point?
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