Dry contact connection / potential-free contact
The Ethernet-based measurement and control systems and intelligent power strips (PDUs) from Didactum offer inputs for dry contacts / potential-free contacts.
| Monitoring product | Number of potential-free inputs | Support for Dry Contact expansion unit* |
| Didactum Monitoring System 50 | 2 | No |
| Didactum Monitoring |
Function of a potential-free contact / dry contact
Potential-free contacts, also called dry contacts, are used to signal condition and status messages. The switching is usually done via a relay. As the name suggests, the switching is potential-free (without voltage).
Connection of a potential-free contact on the monitoring device
All SNMP monitoring systems and power strips include connectors. Connect the wires of the dry contacts to the corresponding screw terminals of the green connector. Each pair of dry contacts shares a common ground. After screwing the two-wire cables to the terminal, insert the terminal into the numbered input socket for dry contacts on the Didactum monitoring device.
Important note: The Didactum monitoring system must be switched off when connecting dry contacts!
Connection assignment SNMP monitoring systems
The monitoring hardware offers two different types of inputs for dry contacts:
- a.) One input contact with a dedicated ground connection (bottom left diagram).
- b.) Two input contacts share a common ground connection (bottom right diagram).