For relays and contactors, you can configure how the coil is to be switched.
In this case, a distinction is made as to whether the coil is to be controlled via
- a terminal / an external signal
- or via an internal voltage / internal switching contact.
The following picture shows the difference:
The configuration differs depending on the configuration used.
Coil via a terminal/external signal.
Since the wiring diagram (Stromlaufplan) cannot determine, which terminals are used to connect the coil of the relay, manual assignment is necessary. This is done in the terminal block in the line of a concrete wire:
Coil via an internal voltage / internal switching contact:
Relays and contactors can also be switched via switching actuators (or other relays).
In conventional installations, relay contacts can control a contactor. In KNX installations, switching actuators can be protected this way, and not every actuator is suitable for switching C-loads. Likewise, this type of use is often observed in PLC and Loxone installations.
The configuration for this is very simple. If you select the option “internal voltage / internal switching contact”, new options appear.
First, select the desired switching contact. These can be the normally open contacts of other relays or channels of actuators.
Moreover, the wiring diagram (Stromlaufplan) must know which circuit is to be responsible for the supply voltage. All fuses (for a 230 V supply) or power supplies (for an extra-low voltage supply) can be selected here.
In the drawing, the coil of the relay or contactor is then automatically inserted into the desired circuit:
