How to Operate an Automatic Door Using Infrared Photoelectric Sensors

An automatic door is not complete without infrared photoelectric sensors to control it. Photo eyes provide a non-contact method to detect people or objects passing through the door and may be used in conjunction with a controller to open the door.

Choose a quality set of industrial infrared photoelectric sensors. It is imperative that sensors are used on an automatic door, not just to open the door, but to prevent the door from closing with a person or object underneath. Photoelectric sensors are ideal for this application because they do not require the door to make contact with the subject to detect their presence. Ultimately, the manufacturer should provide wiring diagrams and installation instructions to help interface sensors or other input devices with the door controller, but the following instructions should give you a general idea of how they should be used.

Mount the photoelectric sensors in a through-beam configuration. This will save you a lot of trouble later. Do not try to mount the photo eyes on one side and use a reflector on the other because you will find yourself constantly cleaning the reflector. Infrared photoelectric sensors provide a stronger and much more reliable beam when they are mounted across from each other. If the photoelectric system that you are using includes an external amplifier, compare the voltage ratings for the photoelectric system and the PLC. If they are a match, connect the output from the amplifier to the door's PLC input card.

Configure the photoelectric system to output all the time, but then take away that output when the photo eyes detect something. This is commonly listed by the manufacturer as a feature known as "Normally Closed", "Light Operate", or "Make Switching." Program the PLC to interpret an output from the photoelectric system as a "false" condition and the absence of that output as a "true" condition. When the PLC reads a "true" condition, it should open the door, and when the condition returns to "false" it should close the door. This does two things, it opens the door when an object is detected and also if the photoelectric system experiences a fault or loss of power.


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How to Find the Door Security Code for a Ford Explorer

If you’ve ever locked the keys inside a Ford Explorer XLT or Eddie Bauer, you know the benefit of having the door keypad to unlock it. What do you do if you’ve lost the code?  XLT and Eddie Bauer model Ford Explorers are equipped with a five-button key pad on the driver's side door that may be used to gain entry to the vehicle or to manually lock all of the doors from that side in the event that the owner misplaces their keys or locks them in the vehicle. This feature is great for those times when you'd otherwise be stranded outside the vehicle.

If you have forgotten the code, you do have the option to pay the dealer where you purchased the Explorer and they will provide the code, but the fee is significant. You can find the code hidden inside the Explorer, so why pay for it? The keypad is not helpful if your keys are locked inside and you don't know the code, but if you still have access to the interior of the vehicle, you should be able to locate the code and memorize it or write it down. You just have to know where to look.

Open the rear hatch of the Explorer. Inside the drivers' side of the storage area, there is an access panel where the jack is stored. Open this panel by twisting the knob and completely remove the panel. You may have to remove the jack from it's holder to see the code.

Using a flashlight, look inside the panel in the direction of the front of the vehicle. There is a label inside with the code typed on it. You may have to look at odd angles to see it or use a mirror to get a better look. Write down the code and then close and lock all the doors of the Explorer. Try entering the code to unlock the doors. Pressing the two buttons on the far right twice simultaneously should lock all the doors. This quick lock function is a universal feature no matter what code is assigned to unlock the doors. If for any reason the code does not work, consult the dealer. They may have to reprogram the keypad, which will also cost you.


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