Mr. Hornberger, what is so special about 'safePxV'?

Armin Hornberger: It is the world's first optical absolute positioning system that has TÜV approval for PLe and SIL3. Pepperl+Fuchs laid the foundation for this in 2011 with the 'PCV' system - PCV stands for Position Coded Vision. At that time, the system was designed for a code band with DataMatrix codes. The DataMatrix code is not only functionally better and more resistant to soiling than a one-dimensional code, it also offers the option of integrating the required SIL3/PLe data volume. Furthermore, position lengths of up to 100,000 m are possible and the position output is not only along the travel path, but also vertically.

You emphasize that only one sensor is required for PLe and SIL3 - how did this work with safe absolute positioning until now?

Armin Hornberger: As German engineering is very inventive, different solutions have been developed for different applications. However, it is generally true for almost all applications that at least two diverse signals are used. Processing these using a safe program module in a safety controller often leads to safety level PLd/SIL2. To achieve the highest level, an independent third signal is usually used.

What does the technological implementation in the new sensor look like?

Armin Hornberger: The basis of the whole thing is the two-dimensional DataMatrix code. It contains two independent DataMatrix codes. This can be recognized by the two colors red and blue. In return, the 'safePxV' sensor has a two-color illumination, red and blue. If the sensor flashes with red lighting, it detects the blue DataMatrix code; if it uses blue lighting, the red codes are detected. This is done randomly and with an internal plausibility check. As a result, the safe PLe/SIL3 position is displayed on the sensor using the Profinet/Profisafe protocol.

What is the difference between 'safePXV' and 'safePGV'?

Armin Hornberger: We make the distinction based on the application. The 'safePGV' - Position Guided Vision - is suitable for navigating driverless transport systems in warehouse and conveyor technology, feeding and production. In addition to the safe X-position, the sensor also provides all the values required for reliable vehicle control. In automotive production, for example, a minimum distance between vehicles can be guaranteed at all times and the protection of all employees involved can be ensured. In addition to the safe data, the system operator can also access angles and Y-positions, meaning that track deviations can be corrected at any time without any problems.

The 'safePXV' is particularly suitable for the safe absolute positioning of electric monorail systems in the automotive industry. In contrast to the 'safePGV', it supplies pure X data, i.e. the position values in the X direction of movement.