CANopen is a widely used standard for CAN systems. Input and output data (process data objects) can be communicated in several ways:
- Event driven: Telegrams are sent as soon as their contents have changed.
- Cyclic synchronous: A SYNC telegram causes the modules to accept the output data that was previously received, and to send new input data.
- Polled: A CAN Remote Frame causes the modules to send their input data.
The Beckhoff CANopen devices support all types of CANopen communication, and correspond to the device profile for digital and analog input/output modules (DS401).
Nine transmission rates from 10 kbaud up to 1 Mbaud are available for different bus lengths. The effective utilisation of the bus bandwidth allows CANopen to achieve short system reaction times at relatively low data rates. The Beckhoff CANopen devices have a powerful implementation of the protocol, and are certified by CiA, the CAN in Automation Association. Through active participation in the CiA’s technical committees, Beckhoff is contributing to the further development of this bus system, and has in this way itself gathered profound CANopen expertise.
Apart from the standard variant (B510), the CANopen modules are also available with integrated tee-connector (B518). This makes the fieldbus wiring much easier. The tee-connector that used to be necessary is replaced by a second M12-type fieldbus input/output. This makes the cabling more compact. Straight or angled versions of pre-assembled plugs or field-assembled plugs can be used.
The node address is set in the range from 1 to 99 using two decimally coded rotary switches. The transmission rate set is detected automatically by the CANopen box (auto baud rate). “Electronic Data Sheets” (*.eds files) for CANopen configuration tools are available. Special I/O parameters not covered by the CANopen standard can be set by means of the KS2000 software (serial connection to the configuration interface of the Fieldbus Box) or via service data object (SDOs).
The extensive diagnostic functions of the Beckhoff CANopen devices allow rapid fault localization. The diagnostic messages (emergency messages) are transmitted over the bus and collated by the master. The status of the network connection, the device status, the status of the inputs and outputs and of the power supply are displayed by LEDs.
Compact Box modules for CANopen are available for all relevant industrial signals. In addition to digital and analog input and output modules including thermocouple and RTD inputs, there are also incremental encoder interfaces available for displacement and angle measurement in addition to serial interfaces to solve a large number of communication tasks.
The CANopen Coupler Box gathers the I/O data from the Extension Box modules over the interference-free IP-Link fibre optic cable. The Coupler Box detects the connected modules and automatically allocates the input and output data to the process data objects. Both data consistency and a clear separation of input and output data are ensured. The Coupler Box has four digital inputs and four digital outputs. Other kinds of signals are available in the Extension Box.