Question 1

1. Why is error proofing important in manufacturing?

Accepted Answer

Error proofing ensures the quality of products leaving a manufacturing plant. The sooner defects are found, the less expensive it is to fix. The image below is a representation of the escalating cost of defects the further they go into the assembly process.

Question 2

2. How is error proofing accomplished?

Accepted Answer

A. There are three general methods for error proofing:

Single point solutions – high accuracy lasers, background suppression sensors, distance measurement
2D vision systems – most expensive and highest cost
Manual checks – least effective due to labor costs and inconsistency

Manual checks are decreasing over time and the single point solutions increasing over time.

Question 3

3. How does PMD time-of-flight technology compare to other single point solutions for distance measurement? What are the advantages of OGD sensors compared to standard sensors?

Accepted Answer

Standard background suppression sensors are lower-cost alternatives, but they can rapidly lose accuracy as sensing distance increases.
Ultrasonic sensors are also lower-cost, but they can be negatively affected by background noise, ambient temperature and target size.
Traditional time-of-flight sensors can be more accurate, but that accuracy comes at a higher cost and typically in a larger housing.
The OGD eliminates the duplicated effort of mounting and wiring both a transmitter and a receiver (or reflector) - the total cost of your solution can be significantly reduced.
The window function, a user-definable object detection range, makes it possible to process objects of different sizes with a single device. Even with changing production lines, there is no need to reconfigure the sensors.

Question 4

4. Why can I only set the set point in the programming menu and not the reset point?

Accepted Answer

The difference between the set and reset points is known as hysteresis. It keeps the output stable if the measured value varies around the set point. The OGD sensors have a fixed hysteresis that depends on the reflectivity of the background and it is shown on the datasheet. For black backgrounds, the hysteresis is approximately 5 mm and for white backgrounds, it is approximately 3 mm.

Question 5

5. What is reflectance?

Accepted Answer

The reflectance indicates the percentage of luminous flux reflected by a surface. The brighter the surface, the higher the reflectance: A white wall reflects up to 85 percent of the light, bright wood panelling only up to 35 percent.

Question 6

6. What are the advantages of time-of-flight measurement compared to conventional triangulation sensor technology?

Accepted Answer

The OGD sensor measures distances with PMD technology, a time-of-flight method that detects objects much more reliably than, for example, CMOS sensors. The sensor especially demonstrates its strength when detecting shiny surfaces or black surfaces with low reflectance. While the OGD can still detect the objects, an CMOS sensor will no longer provide a result.
Even multi-coloured objects such as chipboard or pieces of meat are reliably detected thanks to the PMD technology.
Background suppression and laser light make the OGD extremely reliable even if exposed to external interference such as movements and reflections.
The sensor can detect objects even at extreme alignment angles, while a triangulation sensor must be aligned at an angle of 90° to the object.

Question 7

7. Which OGD part numbers have an output configurable based on reflectivity?

Accepted Answer

All OGD sensors measure reflectivity via IO-Link, but on select part numbers you can set the OGD to display and send a switching signal based upon reflectivity. These part numbers are: OGD250, OGD251, OGD550, OGD551, and OGD582.

OGD laser distance sensor: FAQs