The power supply for the circuit is a UL/CE listed "wall wart" linear supply rated for 24VDC at 1 amp.  This places all system wiring safely within the Class 1 power-limited circuit classification of the National Electric Code and NFPA 70E.  This classification allows the installation of the wiring within the wall (pre or post construction), much in the same manner that a technician would install a new phone line.  (Please consult your local code authority before installation).

The key concept to understand in the design:   Two out of the eight conductors are dedicated to redundant trip of the interlock.  One of these conductors must be floating with respect to the system ground in order to satisfy the interlock.  If any module grounds out this conductor, the interlock will trip off.  A second conductor in the chain must pass 24 volts from one side of the module to the other side.  If the module breaks this 24 volt line, the interlock will trip off.

Each module that is designed to perform a trip function will perform BOTH of the aforementioned trip methods when a trip of the interlock is commanded.  This is a key concept for a properly designed interlock system in that it satisfies the redundancy rule which states that any single failure will either trip the interlock or will not limit the systems ability to trip the interlock when commanded.

The first thing that surprises most customers is the fact that there is no main control panel.  All the modules work together to form an interlock system that is a sum of its parts.  Your system might be small, with one laser table and a single door to interlock, or it may be a room with four or five laser tables and two or three doors.  The Laser Safety Systems 2380 series interlock modules can handle both scenarios.  This provides piece of mind to customers who are starting out with a small laser room but know that the system may grow over time.

Purchase only what you need.  You can add on later as your system grows!

8 conductor wire is used as the interconnect between all major modules.  The connections are identical on each module for the ingoing and outgoing wires.  Eight conductors in, eight conductors out.  The wiring places each module in a "series" chain that allows every module to have complete control over the state of the wires passing through it.

Laser Safety Systems User Manual