PSD-400 Series Light Curtain System

The PSD-400 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 receiver light bar is equipped with individual channel indicator lights. Each infrared channel has its own visible red channel indicator light located near each phototransistor. The channel indicator lights are helpful when aligning the light curtain, and when using the fixed and float blanking features. These indicator lights illuminate when a channel is interrupted or out of alignment.

The PSD-400 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.

OPERATING STATUS INDICATOR LIGHTS

Red, amber, and green status indicator lights are located on the inside lower portion of the transmitter enclosure. Three LED indicators, with the same colors, are also located on the control panel inside the control box enclosure. They indicate the status of the light curtain system. The red indicator light acts as an alignment indicator or indicates a channel is blocked. If the unit is out of alignment or an object is obstructing the sensing field, this LED will be on. If the unit is in alignment, with no obstructions, the green indicator light is on and the red indicator is off. Both the amber and green indicator lights are illuminated when the fixed blanking feature is used. If the float blanking feature is used, the green indicator flashes. If both float and fixed blanking are used at the same time, the green indicator light flashes and the amber indicator light is on.

CHANNEL BLANKING

Provisions are included for programmable fixed and float channel blanking. Blanking this PSD-400 series light curtain is quick and easy. An external return-to-center, key-operated selector switch on the control box cover is used to program the area to be blanked. For fixed blanking, select which channels will be blanked by attaching the blanker(s) to the receiver. Turn the blanking selector switch to the program position and then to the reset position. The channel(s) is now stored in memory as a blanked channel. To turn off the blanking feature, remove the blanker(s) from the receiver and turn the selector switch to the program position and then to the reset position.

To turn the float blanking feature on or off, the float blanking switch on the control box cover is used. This switch can set the float blanking for one-channel float or for two-channel float. Remember, if any blanking feature is used, the safety distance must be reevaluated.

All connections are on boards which are equipped with saddle-clamp-type terminals suitable for 14-gauge stranded wire inside the control box. No separate lugs are required. For reliability, the out-put relays have a captive-contact arrangement. Each unit is protected by a 1-A fuse.

The response time of these light curtains varies depending on their size. (See the chart.) The response time is the length of time that elapses between the interruption of the light beam and the output signal. Response time includes the reaction time of the output device(s) (i.e., relays), and is specified in milliseconds.

These light curtains are designed to meet UL and CSA standards and also have full PSDI (presence-sensing-device initiation) compatibility. This means that the light curtain can be used to start the cycle of the machine while at the same time it can be safeguarding the machine. For further information on PSDI, please see OSHA 29 CFR 1910.217 (h) and ANSI B11.1, B11.2, and B11.3.

Depending on the application, these light curtains can be mounted to the machine with special brackets or on floor stands. For example, power press operators can be protected with a light curtain installed on the front or rear of a machine with auxiliary guarding on the sides. For applications requiring three- or four-sided point-of-operation safeguarding, a mirrored system is available.

A properly designed electrical interface of the machine control to the light curtain allows for redundancy that is required for the reliability of the entire light curtain system. To properly interface the light curtain to the machine, send your electrical and hydraulic schematics to our engineering department for review.

Muting of the light curtain is possible during the nonhazardous portion of the machine cycle. This is used for material feeding or part ejection during the die-opening portion of the cycle.

The PSD-400 series light curtain system has light bar pairs available in 16 sizes, beginning at a 4" field of coverage and increasing in 4" increments to a 64" field of coverage. The part numbers include the PSD-400 control box, one set of light bar pairs, and 20' transmitter/receiver cables. Other cable lengths are available upon request.

To order this system, use Part No. PSD-4XX. Substitute the XX for the field of coverage required. For example, if a 28" field of coverage is required, order Part No. PSD-428. (See chart below.)

Ordering Information