Point-of-Operation Light Curtains

• Meets industry OSHA, ANSI, UL, IEC, and EN safety standards
• 14 and 30 mm resolutions
• Field of coverage from 11.8″ to 70.9″ (300 mm to 1800 mm)
• Scanning range up to 62′
• 2 solid-state OSSD (output signal switching device) outputs—24-V PNP outputs
• Quick response times
• Strobe-light and weld-flash immunity
• Compact light bar housing—1.78″ x 1.42″ (45.2 x 36.0 mm)
• Transmitter and receiver cable lengths from 15′ to 100′ (4.5 to 30 m)
• 7-segment alignment and diagnostics display
• Two-piece design with external device monitoring (EDM)
• Configuration and diagnostic (CDS) software
• Cascading—up to 4 pairs and of different lengths

This photoelectric presence-sensing system (light curtain) is designed to meet safety standards for protecting operating personnel from point-of-operation machine hazards. The EZ-Screen system operates as a stand-alone system to be interfaced into an existing machine control, or a generic interface control is available.

The EZ-Screen system consists of a transmitter and receiver. The transmitter consists of a series of LEDs (light-emitting diodes) which transmit modulated infrared light to the receiver unit. The receiver consists of a corresponding array of photo-diodes that are automatically synchronized with the transmitter LEDs. The EZ-Screen system can be mounted vertically, horizontally, or on any angle depending on the application. The only requirement is that the transmitter must align with the receiver when these units are installed. This system is also cascadable up to four systems. The cascadable pairs can be any length, any number of beams, or have different resolutions as long as each transmitter matches its own receiver.

The EZ-Screen presence-sensing system provides a protective, durable plane of light formed by the aligned transmitter and receiver cells. Any interruption of this plane of light by an object equal to or larger than the MOS (minimum object sensitivity) initiates an output signal to the machine control system. This output causes the machine to stop or does not allow a cycle until the blockage is removed.

The EZ-Screen system is designed in a way that if a component should fail, a total system shutdown results. This is achieved through redundant self-checking circuitry, which compares the actual
system operation with that of a redundant setup. Upon detection of any deviation from the expected status, a shutdown condition occurs.

The plane-of-light portion of the system is formed by a series of high-quality individual optical lenses on every transmitter and receiver channel. This assures the optimal signal-to-noise ratio and allows operation in harsh, oily, and dirty environments. Individual channel lenses create a column of light between each of the active transmitter and receiver channels. The creation of a column of light between transmitter and receiver is called light collimation. Light collimation is necessary to ensure that the infrared light moves from the transmitter to the receiver in a controlled beam that maximizes its efficiency. Additionally, the lens on each receiver channel minimizes the possibility of the infrared light bouncing off shiny objects and fooling the receiver.

The light bars are equipped with status indicators —LEDs and a 7-segment display. These status indicators are helpful when aligning the light curtain and when determining the cause of an interruption in the EZ-Screen system. The LEDs illuminate and the 7-segment display indicates alphanumeric error messages when a channel is interrupted, out of alignment, configured incorrectly, etc.

The EZ-Screen light curtain system modulates each of its LED light sources in a specially coded manner. This modulation virtually eliminates ambient light interference. The light curtain electronically sequences its individual LED transmitters and photo-transistor receivers at a fast rate that prevents any light interference between individual transmitter/receiver sections. This also provides maximum stability and ease of alignment.