machine vision lights
Work Lights

LED Illumination Methods for Machine Vision Lights

Machine vision lights require accurate and robust illumination. Typically installed close to the target object, LED fixtures are currently the lighting system of choice for such applications. The placement of the LED lamps dictate how the light is casted on the object. LED illumination methods covered below include full bright field, partial bright field and dark field lighting techniques.

Full Bright Field Configuration

Full bright field is applicable to machine vision operations when the sample requires multi-directional illumination. A common setup entails the use of a dome accessory, which diffuses the light beams for maximum reflectivity. Furthermore, the LED lamp must be positioned close to the target (but does not have to be pointed directly at the sample), with the sides of the dome serving as a reflector. By comparison, a flat diffuse configuration incorporates a straight diffusing accessory.

For detecting object orientation and inconsistencies (quality assurance), LED back lighting is the preferred technique. A colored LED light, such as blue, green or red, may be used by the operator for distinguishing markings on labels. Flexibility is introduced to LED machine vision lights when the units are equipped with several lighting features. For example, an LED light bar may offer high-color temperature white light, with an optional red beam that can be toggled.

Partial Bright and Dark Field Illumination

Partial bright field illumination utilizes traditional illumination methods. An LED spotlight is applied to the sample, in the same way individuals point a flashlight at an object. This lighting technique is effective for producing contrast and inspecting detail on the surface of the sample.

In machine vision, dark field illumination refers to angled lighting methods, which can be directional, linear or circular. Glare reduction is one of the greatest benefits of dark field illumination, due to the way light is reflected away from the monitoring device (camera).

Industrial Tank Monitoring with LED
Work Lights

Improving Industrial Tank Monitoring with LED Lights and Sensors

Monitoring storage tanks in industrial facilities must be conducted on a regular, sometimes frequent basis. For locations with numerous tanks at the site, such as food processing buildings and storage silos, this can become an issue. Workers are required to do rounds around the operating floor, taking note of various meter readings and documenting the status of the materials or goods inside the chambers. The installation of LED lights, as well as sensors and cameras can boost such meticulous tasks associated with tank maintenance, inspection and daily operation.

Tank Monitoring Lights

Tank monitoring is supported by powerful lighting systems. Compact LED lights can be mounted on the side of the tank, with the light pointed downwards, into the chamber. Alternatively, the lamps may be positioned to illuminate sensors or level readings, which measure the tank’s contents.

Depending on the type of materials being stored, lights used for tank monitoring should be explosion proof to accommodate combustible environments. Furthermore, waterproof housings are common for tanks that store liquids.

Implementing Sensors and Cameras

Ultrasonic sensors are effective for wireless monitoring of tanks and containers. The units work by taking measurements at specific times during the day or night, automatically recording the readings for logging, research and monitoring.

Various settings can be configured, so that in the event of abnormal occurrences, such as overflow, rapid fluctuations in temperatures and more, the sensor may trigger an alarm system to notify plant managers in real-time. Moreover, the alarm system may come with an Leds or stack light for immediate notification around the site for nearby workers.

Remote viewing of tanks is facilitated by cameras. With such equipment in place, supervisors have the option to monitor multiple tanks at once – even located in different rooms. This makes tank management less demanding and reactions to emergencies much faster.

Low Voltage LED Lights
Work Lights

Class 2 Compliance for Low Voltage LED Lights

During construction, installation for LED lighting systems must carefully observe various safety guidelines set forth by the National Electric Code (NEC). For low voltage LED lights, such as wiring, compliance with Class 2 guidelines are recommended.

The standards are designed to reduce risks surrounding fires, shocks and premature lighting failure.

Power and Electrical Wiring

Class 2 regulations for low voltage luminaries must adhere to specific performance standards. When it comes to power supplies, the low voltage 12V DC driver should be 60 watts or lower. Furthermore, 24V DC drivers should operate at 96 watts or lower. As a refresher, a low voltage LED work lights are stepped down from a standard AC voltage (such as 120V AC) to a low, DC voltage (usually 12V DC or 24V DC).

When a Class 1 circuit and a Class 2 circuit are utilized, the components should be separated, according to NEC guidelines. A solution to this concern is the application of a heavy-duty junction box.

Class 2 electric wiring for permanent lighting installations supersede mainstream rubber-based coatings commonly found in mainstream appliances. This requirement is critical because wiring for permanent installations are typically hidden behind walls. If the wiring components are surrounded by insulation, they could be prone to excessive heat generation.

Labeling and Inspections

Streamlining Class 2 compliance can be done by checking the labels of power supplies and wiring components during purchase. In fact, inspectors generally look for markings from an authorized regulator (NRTL) to ensure compliance. Examples of popular NRTLs include UL and ETL.

To avoid delays during inspection and construction, individuals should be ready to provide a wiring diagram for the intended lighting installation. This is usually a requirement in the permit process. Checking for Class 2 compliance is conducted on low voltage lighting units during the rough-in (initial) inspection process.