The Autonics BRQ Series is a side-sensing cylindrical photoelectric sensor family built around a plastic M18 body, red light source, transistor output, and 10–30 VDC operation. The range includes through-beam, polarized retroreflective, and diffuse reflective variants, with cable and connector options, NPN or PNP open-collector output models, IP67 protection, sensitivity adjustment, and Light ON / Dark ON selection by control wire on applicable models.
The BRQ Series is a cylindrical photoelectric sensor platform designed to detect objects without physical contact by using emitted and received light. In this series, the sensing axis is arranged from the side of the body rather than the front face, which is useful when machine geometry, bracket space, or target movement direction makes a side-looking layout easier to implement. The family is offered in through-beam, polarized retroreflective, and diffuse reflective sensing types.
At the hardware level, BRQ uses a plastic housing, M18 × 1 threaded mounting format, red light emission at 660 nm, solid-state transistor output, and either cable type or M12 connector type construction depending on model. The series is intended for indoor industrial use within its rated environmental and electrical limits, with IP67 protection for resistance to dust and water ingress.
A photoelectric sensor operates by transmitting light and evaluating how much of that light is received back at the receiver. The sensor changes output state when the light condition crosses the internal operating threshold. In practical terms, this lets the device detect object presence, passage, interruption, or reflection without mechanical contact, which is why photoelectric sensors are widely used where speed, repeatability, and low wear are important.
In the through-beam version, the emitter and receiver are separate bodies. Detection occurs when an object blocks the beam between them. This configuration offers the longest sensing distance in the photoelectric family and is generally the strongest option when long range and resistance to dust contamination are priorities. In the BRQ Series, through-beam variants are available at 10 m and 20 m.
In the polarized retroreflective version, the sensor works with a reflector. The technical overview explains that the emitter side uses a horizontally polarized filter and the receiver side uses a vertically polarized filter. The reflector rotates the reflected light by 90°, so the receiver accepts valid reflected light from the reflector but rejects false return from many glossy objects. This is why polarized retroreflective sensing is preferred when shiny, mirror-like, glass, or transparent surfaces would confuse a standard retroreflective sensor. In the BRQ Series, this type is rated at 3 m using the MS-2S reflector.
In the diffuse reflective version, the sensor receives light reflected directly from the target itself. This makes wiring and installation simpler because there is no separate receiver or reflector, but performance depends much more strongly on the target’s size, color, material, and reflectivity. The BRQ diffuse models are available in 100 mm, 400 mm, and 700 mm variants, and the manual defines the standard sensing targets using non-glossy white paper.
The BRQ Series also includes a sensitivity adjuster, allowing the installer to set the operating point within a stable detection region. The manual describes a practical tuning method: identify the activation point in the received-light condition, identify the activation point in the interrupted-light condition, and then set the adjuster midway between those points for stable operation. That is an important detail because photoelectric sensing performance is not only about nominal distance; it also depends on how much operating margin remains after installation.
The BRQ ordering structure breaks the family into material, sensing direction, sensing distance, sensing type, power supply, output format, emitter/receiver role, appearance, connection type, and control output. In practical catalog terms, the key user-facing distinctions are sensing method, rated distance, role, connection style, and NPN vs PNP output.
The available sensing types in this side-sensing family are:
Through-beam
Separate emitter and receiver models. Rated distances: 10 m and 20 m. Minimum sensing target: Ø 7 mm or larger opaque object.
Polarized retroreflective
Integrated sensor body used with MS-2S reflector. Rated distance: 3 m. Minimum sensing target: Ø 75 mm or larger opaque object. Suitable where glossy or transparent targets can defeat standard reflective sensing.
Diffuse reflective
Integrated sensor body reading return light from the target surface. Rated distances: 100 mm, 400 mm, 700 mm depending on model. Can detect opaque and translucent materials, with hysteresis up to 20% of sensing distance.
The family is also available as:
Below are the core technical specifications that matter most in engineering selection and commissioning:
Because the BRQ platform combines compact cylindrical mounting, side-looking optics, IP67 protection, red light source, and three different sensing principles, it is suitable for a broad range of machine-level detection tasks. That includes conveyor part presence sensing, object passage confirmation, station entry/exit confirmation, chute or guideway part detection, packaging line count sensing, bracket-mounted edge detection, and short-range machine interlocks where a non-contact optical sensor is preferred. This application list is an engineering inference from the family’s sensing principles, rated distances, and installation characteristics rather than a literal manufacturer application table.
The three sensing principles should be applied differently:
When choosing a BRQ model, start with the same selection logic Autonics uses for photoelectric sensors in general: target characteristics, sensing distance, installation environment, case material, sensing type, power supply, output type, and connection style.
1. Define the target first.
Check whether the object is opaque, translucent, glossy, transparent, small, irregular, or color-sensitive. Through-beam is the least dependent on target reflectivity. Diffuse reflective is the most dependent on target surface condition. Polarized retroreflective sits between them and is especially valuable for glossy or transparent objects.
2. Choose the sensing principle from the machine layout.
If you can mount two opposing devices, through-beam usually gives the strongest margin. If you can place only one body but can mount a reflector, polarized retroreflective is typically the cleaner choice. If neither a second body nor reflector is practical, diffuse reflective is the easiest physical installation.
3. Select rated distance with margin, not just nominal reach.
Diffuse reflective range depends on target reflectivity and size, while retroreflective performance depends on reflector geometry and alignment. The technical overview also notes that reflected-target characteristics affect sensing area and distance, so selecting a model too close to the application limit reduces stability.
4. Check electrical compatibility.
Confirm 10–30 VDC power availability, output type required by the PLC or controller, and cable vs connector preference for maintenance and replacement. BRQ offers NPN and PNP open-collector output models and both cable and M12 connector options.
5. Confirm environmental fit.
The BRQ Series is intended for indoor use and must not be applied in flammable, explosive, corrosive, high-humidity, direct-sunlight, high-radiant-heat, heavy-vibration, heavy-impact, or saline environments outside rated conditions. It should also be kept away from strong noise sources unless grounding and wiring practices are correct.
One of the most common mistakes is selecting diffuse reflective sensing for a target whose surface changes significantly in color, gloss, or material. The technical overview explicitly notes that reflective sensing distance varies with target reflectivity and size, so a setup that works with white paper may become unstable on dark or glossy material.
Another frequent mistake is ignoring mutual interference when multiple sensors are mounted closely. The manufacturer gives explicit countermeasures: maintain spacing based on sensing area, alternate emitter and receiver in through-beam layouts, or use shielding and slits where needed. Reflective types also need spacing and shielding.
Installers also often underestimate the effect of background reflection and disturbing light. Rough mounting surfaces, nearby walls, large background objects, direct sunlight, arc welding, and inverter fluorescent sources can all affect optical stability. The overview recommends shielding, increasing background distance, angling the receiver more than 30° away from disturbing light, and using slits or shields where required.
A fourth mistake is incorrect operation-mode wiring. On applicable models, Dark ON and Light ON are selected through the control wire, and the manual warns that the control wire must be connected correctly when selecting operation mode. Miswiring this lead can make the sensor appear faulty when the real issue is simply inverted logic.
Finally, many field problems come from treating the device like a simple switch rather than an optical instrument. BRQ requires correct target alignment, proper sensitivity setting, and at least 0.5 s after power input before use. Long cable routing near high-voltage lines, missing surge suppression on inductive loads, and ignoring grounding guidance also reduce stability.
Check whether the target and sensing principle match the selected model. A diffuse reflective sensor may not switch reliably on very dark or low-reflectivity targets, while a retroreflective model requires correct reflector placement and alignment. Also verify Light ON / Dark ON wiring through the control wire.
This usually points to marginal received light, background reflection, mutual interference, or incorrect sensitivity adjustment. Re-tune the sensitivity adjuster, confirm stable indicator behavior, increase spacing from adjacent sensors, and reduce disturbing light or reflective background.
Review environmental and wiring conditions. Noise from switching regulators, inverters, servo systems, or poor grounding can affect sensor behavior. Keep wiring short, separate from high-voltage/power lines, and follow the manufacturer’s noise-reduction guidance.
Confirm that the correct reflector is used and that the sensor and reflector are mounted facing each other, at least 0.1 m apart, parallel to the sensing side. Also review whether the target size falls below the stated minimum sensing target.
Check beam alignment, spacing, and target size. The minimum sensing target is Ø 7 mm for the through-beam model, and the overview notes that slits can be used in some through-beam systems to narrow beam coverage when interference or small target detection is an issue.
Through-beam uses separate emitter and receiver and gives the longest distance. Polarized retroreflective uses one sensor and a reflector, with better behavior on glossy or transparent targets. Diffuse reflective reads light reflected directly from the target and is simplest to install, but is more sensitive to target surface properties.
Yes. The manual defines both NPN open-collector and PNP open-collector models.
BRQ is specified for 10–30 VDC ±10% with ripple P-P of 10% or less.
Yes, applicable models support operation-mode selection through the control wire. The manual shows wiring for Dark ON and Light ON.
The product carries an IP67 protection rating, which supports resistance to dust and temporary water exposure within rated use. It is still important to avoid mechanical abuse, excessive cable bending, and environments outside the manufacturer’s stated limitations.
Connector-type models use an M12 4-pin plug arrangement. Cable-type models are also available.
The family uses an M18 × 1 cylindrical body style, with side-sensing optical geometry.