The earliest photoelectric sensors used an incandescent bulb as the light source. While its white light was generally an advantage for registration mark sensing, the disadvantage was the relatively short life of the bulb under normal operation, even shorter when in an application with vibration. The glass of the bulb typically darkened as the filament deposited tungsten onto the inner bulb walls, reducing the light delivered.
Around 50 years ago, the incandescent light source gave way to the light emitting diode (LED), which had a very long life, excellent in applications with vibration, and it maintained its intensity well over its long life. LED’s are offered in visible red, IR, green blue, and white. The sensor, with its LED source, naturally emits light that spreads out with distance, so lenses are employed on the sensor to control the light beam to achieve the desired performance. Even with lensing designed for fixed focus/focal point performance, beyond the focal point the light disperses once again. In short, the traditional photoelectric sensor with a LED source is frequently limited to applications with shorter sensing distances because of this uncontrolled dispersion of light.
Tri-Tronics recently introduced their SmartDot sensor. It uses a visible red laser as the light source. The primary advantage of a laser is the collimated light beam that it produces. Compared to a traditional sensor with a LED light source, the beam remains tight over very long distances. This collimated beam facilitates using the laser to simply see small target area of larger parts, and see small targets at large distances. It also allows sensing an intended target which is beyond unintended targets that are nearer to the sensor. For example, a laser can look through a narrow opening and see the target beyond, even at long distances.
The Tri-Tronics SmartDot sensor features an OLED display, which provides the user with all the relevant information, including a graphic of threshold and setpoint point, scope function, menu steps, and operating instuctions. Numerous on-board timers are accessed via the menu. The sensor provides either NPN/Sinking or PNP/Sourcing output. With a sensor response time of 240 microseconds, it can easily handle fast sensing events. The Tri-Tronics SmartDot sensor is available with either a potted-cable or quick-disconnect.
The Tri-Tronics SmartDot is available in 3 different models: short range proximity (6 inches max), long range (18 inches), or retro-reflective (5 foot).
Excel Automation/Eagle Sensor & Controls is an Authorized Distributor for Tri-Tronics products (since 1989 & 1978 respectively). Contact us for technical, application, or sales support.