How do I identify the Main (M) and Secondary (S) PEARL sensors?
How to tell the Main (M) and Secondary (S) PEARL people counter sensors apart before installation
Table of Contents
Overview
The PEARL Main and Secondary sensors can be identified by the small white M and S markings on the top of each unit. The active indicator directly below the letter identifies whether the sensor is the Main (M) or Secondary (S) unit.
Where do I find the M and S markings?
Look at the top of the PEARL sensor.
You will see two small letters molded into the white plastic:
M = Main sensor
S = Secondary sensor
Directly below each letter is a small circular indicator.
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TIP: The M and S markings are white and can be difficult to see. Look closely at which circular indicator is active directly below the letter.
How do I tell which PEARL is the Main unit?
If the circular indicator under the M is active, you are holding the Main (M) sensor.
In the photos above, the sensor on the left is the Main (M) unit.
How do I tell which PEARL is the Secondary unit?
If the circular indicator under the S is active, you are holding the Secondary (S) sensor.
In the photo above, the sensor on the right is the Secondary (S) unit.
Why is it important to identify them correctly?
The Main and Secondary PEARL sensors have different positions during installation. Identifying each unit before mounting helps ensure that the PEARL pair is installed in the correct orientation.
Remember
M = Main
S = Secondary
Always check the marking and its corresponding indicator before mounting the sensors.
FAQ
The M and S letters are difficult to see. Is that normal?
Yes. The letters are molded into the white housing and do not have contrasting colors, so they may be difficult to see depending on the lighting and viewing angle.
Can I identify the sensor by looking at the circular indicators?
Yes. Look at the top of the sensor and check which indicator is active. The indicator directly below M identifies the Main unit, while the indicator directly below S identifies the Secondary unit.
Should I identify the Main and Secondary sensors before installation?
Yes. Identify both sensors before mounting them so that each unit can be installed in its correct position.