Leuze Releases New Cost-Effective Optical Presence Sensor
Leuze has released the 5B, a new cost-effective photoelectric sensor series that are easy to align and suited for most commercial manufacturing and production environments.
For more than 60 years, Leuze has been at the forefront of sensing technology for the automation industry. Their product lines include switching, measuring, identification, and data transmission sensors. Leuze focuses on providing sensors for the automotive, packaging, and laboratory industries. Recently Leuze released the 5B, a non-contacting presence sensor that uses photoelectric technology.
Leuze’s new 5B optical sensors. Image used courtesy of Leuze
Retro-Reflective, Through-Beam, And Diffuse Sensing
In the automation world, sensors have to detect a lot of things in a typical manufacturing environment, materials, motion, tooling, parts, pallets, and more. Proximity sensors rely on conductive (metallic) material to trigger a signal, however, these devices may not work for every application. A very common alternative is to use a photoelectric sensor to detect proximity.
Photoelectric sensors function by shining a beam of light from a sending unit to a reflector that bounces the beam back to the device (retro-reflective). These devices can also be configured to transmit the beam directly to a dedicated receiving unit (through-beam). Photoelectric sensors are also available deploying sending and receiving electronics in one unit and eliminating the need for a reflector (diffuse sensor).
Three operating modes of optical sensors (retro-reflective, through-beam, and diffuse). Image (modified) used courtesy of Leuze
When these devices detect the light signal, the sensor opens or closes a transistor output (depending on whether the sensor is configured as light on or dark on) which signals the PLC or triggers a relay to energize. This style of sensor is a reliable way of detecting the presence of virtually any material. Typically, these sensors are very compact and come equipped with mounting features and standard M8 connectors or pigtail wire bundles.
A common downside to photoelectric sensors is they require precise alignment between the sending and receiving units. They also do not work well in any environment that would obstruct the receiving unit from detecting the light beam, or when the presence of ambient light in the environment could potentially cause false triggers.
The 5B Optical Sensor
Leuze designed the 5B with the packaging and automotive industries in mind. According to the company, photoelectric sensors should be reliable, easy to set up, and affordable. The new 5B product line is available in three variations, with retro-reflective, through-beam, and diffuse sensors, all of which are IP67 rated.
All of the 5B's variations have an easy-to-use potentiometer to adjust the device's sensitivity to its environment during operation. To ensure accurate sensing and operation, Leuze designed the 5B with a visible light spot and external mounting options for precise alignment. Fitted with a 360° visible LED indicator, the sensor provides operators and technicians with a quick way to determine the energized state. Simply adjust the sending unit until the visible light spot hits the receiving unit or reflector, then look for the status LEDs to change state.
The 5B sensors are also relatively compact, measuring 11 x 32.4 x 20 mm, making them an excellent choice for tight locations. The electrical connections come in pigtail or standard M8 threaded connectors.
Photo sensor box-detection application. Image used courtesy of Leuze
Benefits And Features of Photo Sensors
A common problem with diffuse photoelectric sensors has to do with their limited ability to detect shiny surfaces. A shiny surface can mirror and deflect the light beam away from the sensor, causing obvious results from the depolarized light signal. Leuze says its 5B series sensors are able to successfully sense the proximity of objects with depolarizing glossy surfaces including shrink wrap and shiny printed packaging.
For engineers needing to specify through-beam sensors for applications with high-frequency on/off cycles, the 5B through-beam sensor is capable of up to 900 Hz. Leuze's diffuse model is capable of up to 1000 Hz. Both the through-beam and diffuse model's sensing range extend to 15 meters, while the retro-reflective sensor extends to 6.5 meters. All three models offer a tamper-proof light/dark switching configuration by means of external wiring.