Key Takeaways
Understanding the components, capabilities, advantages, and selection criteria of vision sensors is vital. Explore how these devices compare to vision systems, the tools they use for inspection, and what factors to consider when choosing the right solution for your application.
- Core components: Vision sensors integrate optics, lighting, image sensors, and processors for precise image capture and analysis.
- Functionality: They detect presence, measure dimensions, and verify assembly accurately.
- Vision sensors advantages: Compact, cost-effective, and easy to deploy, vision sensors can handle many industrial tasks.
- Vision sensors vs. vision systems: Vision sensors handle simpler tasks, while vision systems tackle complex, multi-step processes.
- Application tools: Pattern matching, edge detection, and measurement tools solve inspection challenges efficiently.
- Selection criteria: Choose based on application needs, such as speed, resolution, and environmental conditions.
In factory automation, many kinds of sensors are used to gather data for inspection or to trigger other devices. These sensors fall into multiple categories but photoelectric, fiber optic, proximity, ultrasonic, and vision are the most common.
Vision sensor capabilities
Sensors are faster than human inspectors, more objective, and work continuously.
Vision sensors detect their targets by pattern, feature, and color, covering wide areas on fast-moving lines. Most support several communications protocols to communicate with upstream and downstream equipment and to indicate whether a part is present or passes inspection.
While point source sensors must be perfectly aligned to work correctly, vision sensors are designed to handle a high degree of variability. This allows operators to use them in pre-configured cells without needing to make costly and time-consuming changes. Vision sensors:
- Offer greater flexibility, efficiency, and versatility than many other types of sensors
- Can perform multiple inspections in a single image
- Generate additional rich data for quality and process improvement
- Handle misalignment easily
Other sensor types
Low-cost photoelectric sensors can perform only a limited number of simple tasks, such as position verification and basic counting. They cannot distinguish between patterns or colors. And with their rigid mounting setup, they cannot handle misalignment or variability common in most work cells. In some cases, different types of sensors act as complementary technologies. Photoelectric sensors may be used in conjunction with vision sensors to communicate whether a part is on its way in order to trigger the camera in a machine vision system.
How do vision sensors work?
Vision sensors perform inspections by finding the part in an image, then looking for specific features on that part. Once the field of view (FOV) is set, an operator can run multiple vision tools within the entire image to inspect multiple features for presence, completeness, or orientation—all in a single image capture. Even though data output is binary (good/no good), data in aggregate can be used downstream to improve processes and perform diagnostics on a particular work cell.
A network of vision sensors can be easily linked to plant and enterprise networks, allowing any workstation in the factory to view results, images, and data for process control. Depending on the specific system or application, vision software configures camera parameters, makes the pass/fail decision, communicates with the factory floor, and supports HMI development.
Most vision sensors:
- Require no programming
- Provide easy guided set-up through user-friendly vision software interfaces
- Integrate easily into larger systems
- Provide single- and multiple-point inspections with dedicated processing
- Offer built-in Ethernet communications
- Can exchange data with other systems to communicate results and trigger subsequent stages of an inspection