Pull-up / Pull Down

You can configure Opto Trigger 5 according to the electrical source of the incoming signal: 

In most application scenarious, you will need to configure OPTO trigger 5 to pull-up .

Pull-up variant:

Pull-up is the default setting. The DIP switch for transistor mode (switch 3) is in OFF position. The LED P DN is OFF:

Pull-down variant:

The DIP switch for transistor mode (switch 3) is ON position. The LED P DN is ON: