What Is the Difference Between R1, R2, and R3 Terminals?

R1 terminal:

• The R1 input is the primary input for reversing devices when there are no monitored devices in the system.
• The R1 input is special because it is used in tandem with the P+ terminal.
• P+ is a +24V output toggled off and on during operator boot-up and on close to check for a delay with R1.
• This delay indicates that there is a device connected to the R1 terminal instead of a jumper.
• This is done to stay compliant with UL 325 standards which require at least one photo-eye to be connected to the system for the door to close automatically.

R2 terminal:

• The R2 input is for monitored devices and takes priority over R1 when connected.
• This input is always communicating with the photo-eye itself and is the safest.

R3 terminal:

• The R3 input is a simple relay-based input that requires +24V to stay active.
• This input can only be used as a secondary or tertiary input when R1 and/or R2 are hooked up.