SAFETY & MEASUREMENT light curtains overview SAFETY

September 09 2024 | Blog Post, Venus Automation

In manufacturing and automated industries, the criticality of worker safety remains prevalent; and machinery that presents as hazardous during operations thus needs to be safeguarded with boundaries put in place. Even at the best of times, an unknowing factory visitor or a simply zoned out operator who has lost focus is all that it takes for an accident to happen. Thus, ‘out-of-bounds’ areas present as crucial in keeping humans safe around machines to upkeep proper procedure, functionality, and efficiency. This is where light curtains from ReeR come into play. Offered in various configurations for a variety of applications, ReeR light curtains think safety even when humans forget to.

Utilising projection of infrared beams (of which the number and spacing is application-dependent), ReeR light curtains work to change output voltage signals which can then be used as logic inputs for safety PLCs and relays. This technology proves its usefulness in guarding humans from hazardous machinery, creating boundaries, guarding perimeters, and creating conditions that would halt machinery if an unusual object (that does not satisfy the light curtain’s conditions) is detected in an assembly line.

In automated processes, precision measurement is required to accurately detect/verify the profile and position of objects. Whether it be counting and sorting the number of different objects passing through an area such as a conveyor belt, or monitoring the levels of materials/pallets, light curtains prove their value. ReeR products such as the MICRON are light curtains with configurations dedicated to precision measurement and monitoring.

Light Curtains and their use in Industry

In industrial and automation applications, light curtains provide a critical layer of safety – and can also be used for precise measurement. In safety, light curtains enable a seamless communication between the operator environment, machines, and safety relays. Utilising the projection (transmission) and reception of infrared beams across a plane of beams, the voltage output of a light curtain can be monitored and use as logical input for safety PLCs. Dependening on the configuration of the light curtain, the spacing of the beams can trigger a safety output (halting of operations), for something as small as a finger to something as large as one’s whole body.

Furthermore, measurement light curtains can be used in counting, dimensioning, and automating robots; such as an AGV (automated guided vehicle) using onboard light curtains to measure heights, distances, and widths to determine its next actions. Measurement light curtains are often found in automated, conveyor style machinery as well; where the light curtains can be used to ensure that items passing through its field are counted, positioned, and oriented correctly.

Key overview of REER LIGHT CURTAINS

Purpose and Function

ReeR light curtains are crucial for ensuring safety and precision in industrial environments. Concerning the safety of the automated environment, a ReeR light curtain can detect objects the size of fingers, hands, or whole bodies. These light curtains can then be placed at out-of-bounds areas that should not be crossed during machinery operating. Upon detecting an object passing through this boundary, light curtains can then signal for machinery to stop – separating humans from hazards.

Light curtains work on the principle of line-of-sight transmission. With one end of the light curtain projecting (emitter) beams across to the other (the receiver). Each beam constitutes the total voltage reading sent by the receiver via a cable, and blocking these cables will change the voltage output. The simplicity of this voltage change facilitates a rapidly available signal for monitoring via safety PLCs; enabling an effectively instantaneous action in response to a beam being blocked.

Applications

ReeR light curtains are offered in several varieties. The EOS series light curtains are compact photoelectric sensors, and are used when space is a premium. Often used for machine guarding, EOS light curtains can monitor the upper, middle, and lower sections of a boundary area. EOS light curtains are also offered in a master-slave configuration, and can thus be run in series and span long distances to create large, safeguarded boundaries. Offered in two degrees of safety categorisation, depending on the application, an EOS light curtain is guaranteed to safely work and, should failure come, it will fail safe.

ReeR’s SAFEGATE series are a family of light curtains that can be operated over large distances – up to 80 metres. SAFEGATE light curtains are often used for their muting functions, which use mounted parallel or crossed beams emitted from ‘muting arms’ to permit certain objects through the light curtain without causing a trip signal. SAFEGATE are highly safe, robust light curtains that are offered in programmable variants, allowing for a customisable light curtain using a computer.

ReeR’s ADMIRAL light curtains are larger units reserved for higher-risk environments, making it suitable for demanding industrial settings. Variants of the Admiral are offered with watertight housings and can operate at long distances (depending on the variant, this is 25 or 80 metres). ReeR Admiral variants offer a dual-beam system, making it ideal for outdoor applications and harsh environments – where the dual beams will reduce the sensitivity of the curtain to avoid false-trips due to outdoor elements such as birds, leaves, and inclement weather.

features

Muting: ReeR light curtains such as the SAFEGATE SMO include the option for separately sold muting arms. These muting arms work by projecting either parallel or dual-cross beams, and work with the light curtain to permit objects of certain heights and widths to pass through the light curtains without causing a fault/trip.

Safety Compliance: The majority of ReeR light curtains, such as the SAFEGATE, the Admiral, and the EOS4 are offered at a safety level of Category 4 or PL e.

Beam Count/Resolution: ReeR light curtains can be fitted with a variety of beams, the spacing of these beams is offered in a variety of resolutions. Resolution is simply the number of beams there are over a given space, and are what determines the size at which an object will be detected by the light curtain. An example of this includes ReeR’s EOS4, which is offered in resolutions (beam spacings) of 14mm, 30mm, and 90mm.

Programming: Products such as ReeR’s SAFEGATE SMPO are fully programmable. They offer an IDE (integrated development environment), called Safegate Configurator – a simple yet powerful tool used to set up your light curtain for your applications. Custom profiles, parameters, real-time monitoring, self-diagnostics, and fault detection are all a possibility with the SAFEGATE SMPO. Otherwise, in cabling and wiring configurations, other ReeR light curtains can be configured in different modes and feature automatic or manual resets, and options for external monitoring.

integration

ReeR light curtains are all compatible with ReeR’s family of safety PLCs, MOSAIC. Using ReeR’s IDE, MOSAIC Safety Designer (MSD), light curtains can be configured, controlled, and monitored; and its outputs can be interpreted and used as control signals for machines connected to the relay. Furthermore, relays from Wieland such as the SNO 4602K and SNO 4602A are also capable of interpreting electrical outputs from the light curtain and using them to mechanically connect/disconnect the relays OSSD-dependent outputs.

Understanding the product - ReeR MICRON

Unique to ReeR’s safety light curtains, the MICRON line are a family of light curtains dedicated to the measurement aspect of automation. Utilising the technology of projected beams between an emittor and a receiver, MICRON light curtains use a number of beams and different protocols to act as a control signal.

When an object blocks the beam, the analogue output of the MICRON will change – and depending on the setup – these can then be used to configure measurement and counting parameters. The ReeR MICRON receiver can be plugged into a PC via USB, and the conditions at which a control signal is sent can be configured dependent on applications.

MICRON - Voltage Triggered (AV)

The Micron AV light curtain from REER uses a 0-10 VDC analog output to convert the status of its light beams into a measurable voltage signal. When an object interrupts a beam, it causes a change in the detected light pattern. This interruption is translated into a voltage within the 0-10 VDC range, where 10 V represents no interruptions and 0 V indicates maximum interruption or detection. This analog signal is then used by connected control systems to determine the size, position, or flow rate of objects passing through the light curtain. The 0-10 VDC output simplifies integration into various measurement and control systems, allowing real-time monitoring and precise measurement of objects in industrial applications.

MICRON - Current Triggered (AC)

Current triggered devices are more prevalent in the automation industry, and thus ReeR have provided another model by which its outputs are controlled by current regulation.

The MICRON AC light curtain from ReeR utilizes a 4-20mA or 0-16mA current output to convert the status of its light beams into a measurable control signal. When an object interrupts a beam, it alters the light pattern, which is translated into a corresponding current within the 4-20mA or 0-16mA range. In this system, 20mA (or 16mA) represents no interruptions, while 4mA (or 0mA) indicates maximum beam interruption. This current signal is fed into control systems to determine the size, position, or flow rate of objects, enabling real-time monitoring and precise control in various industrial measurement applications.

MICRON - Antivalent Outputs (C)

The Micron C light curtain from REER features antivalent (complementary) outputs, meaning it provides two distinct signals: one normally open (NO) and one normally closed (NC). When all beams are clear (no interruption), the NO output remains inactive (off), while the NC output is active (on). If an object interrupts the light curtain, the NO output is activated (on), and the NC output is deactivated (off). This complementary arrangement ensures redundancy and allows the system to easily detect changes in the beam status for triggering alarms, safety stops, or other control actions in industrial applications.

MICRON - IO-Link Protocol (IOL)

Micron IOL light curtains from ReeR use the IO-Link protocol for advanced digital communication via a serial output. Instead of traditional analog or discrete signals, the IO-Link interface allows detailed, bidirectional data exchange between the light curtain and an IO-Link master. This enables real-time transmission of beam status, diagnostics, and configuration settings over a single cable. The digital nature of the IO-Link protocol enhances precision and flexibility, allowing easy integration into industrial systems and providing comprehensive monitoring and control. With IO-Link, users can track beam interruptions, adjust settings remotely, and gather detailed information for more complex object detection and measurement applications.

MICRON - RS485

RS485 is a robust serial communication protocol designed for long-distance data transmission in electrically noisy environments. It supports multi-device networks using differential signaling to reduce interference and maintain signal integrity. Micron RS485 light curtains from REER leverage this protocol to transmit real-time beam status, diagnostics, and configuration data between the light curtain and a control system. The RS485 interface ensures reliable communication across long distances and in complex networks, making it ideal for precise control and monitoring in industrial automation and data acquisition applications.

DESCRIPTION

The ReeR MICRON MI AC Line of measurement light curtains are current-regulated light curtains that use current output (of which is altered by obstruction of beams) to send control signals. They are configured in ways to facilitate applications for precise measurement in a variety of heights and resolutions.

SPECIFICATIONS

Connectivity: M12 5-pin connector (emitter), M12 8-pin connector (receiver), USB cable for programming/configurations

Operating Current: 0-16 mA, or 4-20 mA

Controlled Height (mm): 75 – 2990

Beam Spacing (mm): 5, 10, 25, 30, 50, or 75

Maximum Range (m): 2 -18

DESCRIPTION

The REER Micron M5 photocell is used in muting arms for light curtains to facilitate the controlled passage of objects through safety zones. In applications where light curtains need to be temporarily disabled (muted) to allow objects to pass without triggering a safety stop, the M5 photocell detects the presence of the object. It acts as a secondary sensing element that signals the light curtain to ignore interruptions caused by the object, ensuring continuous operation while maintaining safety. The M5 photocell is typically integrated into the muting system to accurately monitor and manage the passage of objects, enhancing workflow efficiency while upholding safety standards.

SPECIFICATIONS

Coding: A or B Coding

Beam Count: 5

Beam Spacing: 10mm

Range: 0 – 3.5 metres (for M Series), 0 – 5 metres (for MH Series)

Connectivity: M12 5-pin connector

OFFERED PRODUCTS

ReeR MICRON M5-A
ReeR MICRON M5-B
ReeR MICRON M5H-A Long Range
ReeR MICRON M5H-B Long Range

types of Reer eos2 and eos4 safety light curtain Available

Model Number	Protected Height (mm)	Controlled Height (mm)	Overall Height (mm)
EOS4 151X	160	150	213
EOS4 301X	310	300	363
EOS4 451X	460	450	513
EOS4 601X	610	600	663
EOS4 751X	760	750	813
EOS4 901X	910	900	963
EOS4 1051x	1060	1050	1113
EOS4 1201X	1210	1200	1263
EOS4 1351X	1360	1350	1413
EOS4 1501X	1510	1500	1563
EOS4 1801X	1810	1800	1911

Model Number	Protected Height (mm)	Controlled Height (mm)	Overall Height (mm)
EOS2 153X	160	150	213
EOS2 303X	310	300	363
EOS2 453X	460	450	513
EOS2 603X	610	600	663
EOS2 753X	760	750	813
EOS2 903X	910	900	963
EOS2 1053X	1060	1050	1113
EOS2 1203X	1210	1200	1263
EOS2 1353X	1360	1350	1413
EOS2 1503X	1510	1500	1563
EOS2 1803X	1810	1800	1911

Model Number	Protected Height (mm)	Controlled Height (mm)	Overall Height (mm)
EOS4 153X	160	150	213
EOS4 303X	310	300	363
EOS4 453X	460	450	513
EOS4 603X	610	600	663
EOS4 753X	760	750	813
EOS4 903X	910	900	963
EOS4 1053X	1060	1050	1113
EOS4 1203X	1210	1200	1263
EOS4 1353X	1360	1350	1413
EOS4 1503X	1510	1500	1563
EOS4 1803X	1810	1800	1911

Model Number	Protected Height (mm)	Controlled Height (mm)	Overall Height (mm)
EOS2 155X	160	150	213
EOS2 309X	310	300	363
EOS2 459X	460	450	513
EOS2 609X	610	600	663
EOS2 759X	760	750	813
EOS2 909X	910	900	963
EOS2 1059X	1060	1050	1113
EOS2 1209X	1210	1200	1263
EOS2 1359X	1360	1350	1413
EOS2 1509X	1510	1500	1563
EOS2 1809X	1810	1800	1911

Model Number	Protected Height (mm)	Controlled Height (mm)	Overall Height (mm)
EOS4 155X	160	150	213
EOS4 309X	310	300	363
EOS4 459X	460	450	513
EOS4 609X	610	600	663
EOS4 759X	760	750	813
EOS4 909X	910	900	963
EOS4 1059X	1060	1050	1113
EOS4 1209X	1210	1200	1263
EOS4 1359X	1360	1350	1413
EOS4 1509X	1510	1500	1563
EOS4 1809X	1810	1800	1911

Types of REER Micron Measurement Light Curtain Available

MODEL NUMBER	Overall Height (mm)	Controlled Height (mm)	Range (m)
MICRON MI 150 AC	223	145	2.5
MICRON MI 300 AC	363	295	2.5
MICRON MI 450 AC	523	395	2.5
MICRON MI 600 AC	663	595	2.5

MODEL NUMBER	Overall Height (mm)	Controlled Height (mm)	Range (m)
MICRON MI 750 AC	823	745	2.5
MICRON MI 900 AC	973	895	2.5
MICRON MI 1050 AC	973	895	2.5

Integration and Connection - Accessories

ReeR offer a range of cables for their light curtain products, with the CD line designated for emitter light curtains and their 5-pin M12 Connectors. The CD line are offered in lengths from 5 metres and up to 25 metres.

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ReeR offer a range of cables for their light curtain products, with the C8D line designated for receiver light curtains and their 8-pin M12 Connectors. The C8D line are offered in lengths from 5 metres and up to 25 metres.

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ReeR offer a range of cables for their light curtain products, with the C12D line designated for SAFEGATE receiver light curtains and their 12-pin M12 Connectors. The C12D line are offered in lengths from 5 metres and up to 25 metres.

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