Problem:
Some Beckhoff i/o terminals are not active and status LEDs are off, control does not respond to commands.
Possible Causes & Resolutions:
- The 24Vdc supply of the EK1100 coupler or the EL9410 intermediate supply terminal is missing or the voltage is too low > Check all connections, measure voltage, check fuses.
- Bad contact between the terminals > Switch off the main power and remove the terminals. Clean the contact between the terminals.
- Defective EL9410 intermediate supply terminal > Exchange terminal.
- Defective EK1100 coupler > Exchange coupler.
![](https://www.canman.ch/wp-content/uploads/2023/01/io-terminals-EK1100-and-EL9410.jpg)