Engineering Guide for Light Curtains: Overview and Applications

Automation and Control Sensors Transducers
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Article summary

This is the lead article in a series dedicated to light curtains. It is part of a guided engineering initiative designed to complement the manufacturer’s documentation by providing guidance at the application and selection level—we will help you select solutions for your application.

Introduction

Recently, I’ve been working with a variety of SICK sensors. In this post we will explore light curtains including those that are safety-rated and those that are designed for general-purpose industrial settings. An example is the safety-rated deTec4 on the workbench as shown in Figure 1.

Figure 1: Close-up of a SICK deTEC4 series light curtain.
Figure 1: Close-up of a SICK deTEC4 series light curtain.975×732 103 KB

Figure 1: Close-up of a SICK deTEC4 series light curtain.

Light curtain facts

Here are a few light curtain facts that I learned along the way:

  • Not all light curtains are safety devices. There are applications where a light curtain sensor is the optimal solution. For example, a light curtains may be more flexible than a retroreflective sensor, as they can detect objects of multiple heights that would otherwise be missed by a single beam.

  • The IR beam can be seen using a cell phone as shown in Figure 2. Note that the SICK SLG-2 is not a safety sensor. As a rule, safety light curtains are yellow.

  • DigiKey sells light curtains with beam count ranging from 4 to 240.

Figure 2: The infrared beams for this non-safety SICK light curtain are visible as purple dots to a cell phone.
Figure 2: The infrared beams for this non-safety SICK light curtain are visible as purple dots to a cell phone.975×732 70.8 KB

Figure 2: The infrared beams for this non-safety SICK light curtain are visible as purple dots to a cell phone.

List of topics

Topics are organized into clusters. Please follow the links for a detailed description of each topic:

Help us to help you

If you would like to know more about light curtains, please add your question in the comments section. We may answer directly or move your question to the core of this guided learning series.

Best wishes,

APDahlen

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About this author

Aaron Dahlen, LCDR USCG (Ret.), serves as an application engineer at DigiKey. He has a unique electronics and automation foundation built over a 27-year military career as a technician and engineer which was further enhanced by 12 years of teaching (interwoven). With an MSEE degree from Minnesota State University, Mankato, Dahlen has taught in an ABET-accredited EE program, served as the program coordinator for an EET program, and taught component-level repair to military electronics technicians. Dahlen has returned to his Northern Minnesota home and thoroughly enjoys researching and writing articles such as this.