The Model CE is an infrared safety light curtain that is designed to the IEC 61496 standard. When properly installed, it protects the machine operator by passing an invisible infrared light beam across an area to be guarded and examining whether or not the light beam(s) are blocked. If the light beam(s) are blocked, monitored solid state outputs will open, issuing a “STOP” command to the machines normally closed (N.C.) “STOP” circuit. The System is composed of a transmitting unit (EMITTER), and a receiving unit (RECEIVER). The entire system is control reliable Category 4 (per IEC EN 954-1). A single fault anywhere within the Model CE will not prevent at least one of the solid state outputs from opening up, (allowing a “STOP” command) when either a beam is broken or an internal fault occurs.

Theory of operation.  
The Model CE protects an area by projecting a curtain of infrared light. The infrared emitters and receivers face each other across the field to be protected. Each emitter/receiver pair is spaced along the length of the pylons at regular intervals from .5" (13mm), up to 8" (203mm) depending on the application. The smaller spacing are for finger guarding, the larger spacing are for body protection.
The emitter/receiver pairs are scanned sequentially (one at a time) by a very short pulse of infrared light starting from bottom (cable end), and working up to the top, until every beam pair has been scanned. Two 16 bit computers in the emitter pylon and two 16 bit computers in the receiver pylon control the operation, as well as cross check each pylon.