Camera-Based Linear Positioning (PCV, PXV)

The PCV, PXV, safePXV, and safePXV/PUS Data Matrix positioning systems from Pepperl+Fuchs use Data Matrix codes for precise positioning. They consist of a 2-D camera system—a read head—and a Data Matrix code tape or metal code bar. This unique combination ensures maximum precision and extremely reliable positioning.

The self-adhesive code tape or metal code bar is attached to a fixed part of the system or plant, such as the wall of an elevator shaft or the mounting rail of an electric monorail system (EMS). The 2-D read head is mounted on a "vehicle" that moves parallel to it, e.g., on the elevator car or on the carrier of the EMS. Code redundancy and large reading windows enable the PCV, PXV, safePXV, and safePXV/PUS Data Matrix positioning systems to reliably detect a position, even if the code tape is dirty or damaged. They can also bridge code tape gaps without any problems.

The systems differ in reading window and Data Matrix code size: PXV, safePXV, and safePXV/PUS offer even greater mounting tolerance with their large reading windows. The positioning systems can be parameterized via Data Matrix code cards, PC, or the controller, which makes them easy to get up and running. Typical applications for Data Matrix positioning systems include the positioning of skid and electric monorail systems, lifting and elevator systems, studio technology, and cranes. 

With the safePXV and safePXV/PUS, Pepperl+Fuchs offers two safety versions of the PXV positioning system that enable safe absolute positioning up to SIL 3/PL e. The safePXV positioning system is based on a combination of 2-D camera technology and multicolor Data Matrix code tape. The preinstalled firmware checks the plausibility of the X position values using red and blue illumination color in combination with a mulitcolor code tape. The safe X position data can then be processed in the PLC without additional plausibility checks—all because of the reliable, self-monitoring sensor technology.

The safePXV/PUS positioning system consists of the safe evaluation unit (Position Unit Safe, PUS) and a safePXV/PUS read head. The evaluation unit acts as a safe gateway to the fieldbus: It processes the redundant signals from the safePXV/PUS read head, creates a safe position X value, and derives a safe speed value from it. In addition to the safe and non-safe data, it also transmits diagnostic data, Y tolerance warnings, or a quality rating of the code tape. The system supports the common safety protocols PROFINET & PROFIsafe and EtherCAT®/Fail Safe over EtherCAT® (FSoE) in order to transmit the acquired data from the sensor to a safe control system. The safe X position or safe speed can be used to realize common safety functions such as safe limited position (SLP) or safe limited speed (SLS) by the supervising SPLC or other.