A potential-free contact is used to transfer a state between electrical devices. The contact is usually made via a relay or an optocoupler .
The electrical circuits of the devices to be connected are galvanically decoupled from one another. This solution is the simplest and safest method to e.g. B. to transmit digital data points electrically.
In other handover procedures, e.g. B. the S0 interface , the polarity of the contacts, the correct grounding, the voltage ( direct current / alternating current ) and the current flow must be observed when connecting. Due to the electrical coupling of the devices, if one device malfunctions, the other device can easily be disturbed or destroyed.
This is why potential-free contact is the preferred type of transmission between two devices in industrial automation technology and building automation at the field level .
- Fault signaling contacts of heating, ventilation and cooling systems, air conditioning systems, frequency converters, blind and roller shutter controls, ...
- Signaling contacts of alarm systems, light controls, DDC-GA controls
- Meter contacts for heat meters , water meters and gas meters
- Contacts on safety switching devices