Leuze (Germany) offers the CML 700i light curtain with a CANopen option. The interface features data-rates up to 1 Mbit/s.
The light curtains of the CML 700i series are designed as measuring and object-detecting, configurable, multi-sensor units. Depending on the configuration and model, the devices are suitable for a variety of tasks with various resolutions and can be integrated in different control environments. The total system of the light curtain consists of a transmitter and a receiver, including the connection and interconnection cables. The products can be linked via CANopen to a host controller.
Due to the fastening concept and the optional plug outlet to the rear, the CML 700i light curtains can be integrated. Moreover, this results in a blind area of just 23 mm and the possibility to mount the light curtain without detection gaps close to the transport system. Thanks to the plug design, the user can also cascade the devices if measurement lengths of greater than 3 m are required. An integrated alignment mode and the display of the received signal level in the display simplify and accelerate alignment.
The CANopen interface uses M12 connectors and implements a manufacturer-specific profile. It features asynchronous and synchronous PDO communication and Heartbeat functionality. The device characteristics start with the beam spacing parameter providing the numbers of physical/logical individual beams and cascades (16 individual beams). The light curtain supports different operation modes including parallel, diagonal, and crossed beam scanning. The counting direction and the smoothing are also configurable. It is also possible to accumulate measurement values and retained them over the duration of the integration time configurable in milliseconds.
To prevent mutual interference, multiple light curtains can be operated with a time offset with respect to one another (cascade). In this case, the host controller generates the cyclical trigger signal; the light curtains start their measurement after delay times, which are to be set to different values. For many applications, the supplier recommends that the teach values should be stored in non-volatile memory. Depending on the function reserve selected for the teach event, the sensitivity is higher or lower (high function reserve = low sensitivity; low function reserve = high sensitivity). Up to four beam areas can be deactivated. With auto-blanking activated, up to four beam areas are automatically suppressed during teaching. The auto-blanking should only be activated during commissioning of the light curtain to suppress interfering objects. In process mode, auto blanking should be deactivated.