You will need to create an Action in the Controller Profiles, this action will affect all Terminals  Go to Setup/Controller Profiles

 Go to Actions, then Add Action

Describe the Action and Choose Lockdown Mode for the Type.  Click the Enabled Radio Button, Do Not Choose a Time Pattern.

Now Create an Input in the Reader Profile where the Lockdown Input is wired to.  Either Input 1 or Input 2 depending on where the wires land Go to Setup/Reader Profiles/ Once in the Reader Profile, select the Inputs tab, create new input.

Name the Input Accordingly,  choose Lockdown as the Type.

Make sure you are choosing the correct input, then save.

Your input button will now Trigger a Lockdown when pressed.