The PLV-JA-111R case is used for external mounting of a JA-111R board. The JA-111R board is usually mounted in the JA-100 control panels, but if you want to have the circuit outside the control panel, ie externally, you will need a cabinet.
To do this, remove the JA-111R from its holder in the control panel, click the JA-111R printed into the cover, and then mount the PLV-JA-111R cabinet externally from the control panel.
Also note that the cabinet comes with a terminal for the JA-111R.