How To Verify Photo Eye Alignment Using Test Points

How To Verify Photo Eye Alignment Using Test Points

Overview

USAutomatic photo eyes come equipped with test points for measuring the alignment strength between the transmitting and receiving eyes. In this article you will learn how to use a volt meter to measure these test points to ensure the photo eyes are aligned optimally.

While the transmitting photo eye can be hardwired for power, most installations use the 3.6v AA batteries. As the batteries in the transmitting photo eye die, the IR beam that it creates gets weaker. If the photo eyes are barely aligned to begin with, they may lose alignment after 6 months rather than the 18+ months the batteries are rated for. Getting the alignment strength as close to maximum as possible will ensure the batteries last as long as they should, saving you money on battery replacements

Applies to Part Number(s)

  1. 550011

What You Need

  1. Small Phillips head screw driver
  2. Voltage meter capable of reading DC voltage

Procedure

Identifying the Test Points

The test points for measuring alignment strength are located on the left-center and right-center of the receiving photo eye labelled “TP+” and  “TP-”.


Measuring the Test Points

  1. Set the volt meter to DC voltage.
  2. Insert the positive lead into 'TP+'.
  3. Insert the negative lead into 'TP-'.
Info
The leads should be able to hang in the contacts, allowing you to step out of the way so the eyes can realign.

Adjusting the Photo Eye

The receiving photo eye has two alignment indicator LEDs: 
  1. RED means the eye is not aligned.
  2. GREEN means the eye is aligned.
Adjust the photo eyes as necessary to achieve as close to 5v as possible.
  1. The MINIMUM alignment strength is 3v.
  2. The MAXIMUM alignment strength is 5v.

TP-/TP+ readings (DCV)

Signal Strength

Alignment

0 Vdc

No Signal

NOT Aligned

3 Vdc

Minimum useful signal

POOR Alignment

5 Vdc

Maximum useful signal

STRONG Alignment