BECKHOFF C9900-G0xx - Manual (Page 22)

Installation
20 C9900-G0xx
4.2 Connecting the push-button extension
Attention
The power supply plug must be withdrawn
Please read the documentation for the external devices prior to connecting them.
Do not connect or disconnect the cables during a thunderstorm!
When disconnecting a plug connector, always handle it at the plug. Do not pull the cable!
4.2.1 Connecting cables
The connections are located at the rear of the push-button extension and are documented in section
Connections .
When connecting cables, please adhere to the following order:
 Disconnect all components from the power supply.
 Connect all cables to the push-button extension and the devices to be connected.
 Ensure that all screw connections between connectors and sockets are tight!
 Reconnect all devices to the power supply.