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A Brief Introduction To CANopen®
CANopen® is a network technology optimized for the usage in industrial control environments, in machine internal networks and in embedded systems (any control unit deeply "embedded" in a device with electronics). The lower-layer implementation of CANopen® is based upon CAN (Controller Area Network) which is implemented on microcontrollers of more than 22 chip manufacturers.

In industrial control terms CANopen® is a "Fieldbus", such as DeviceNet, Smart Distributed Systems, InterBus-S and others. Some applications use derivations from RS485 for similar embedded networks. However, with RS485 the network designer / developer needs to invent many communication routines whereas CANopen® features a pre-defined set of network communication functionality.

As the basis technology is included in so many low-cost and low to medium-performance components, it is well suited for cost-sensitive / high-volume applications, other applications using 8-bit to 16-bit microcontrollers and low-power applications. Some typical applications are shown in our listing of application examples.

The functionality provided by CANopen® allows the configuration of each network node by a network master or configuration tool. The configuration parameters set the communication behavior of a device and allow to set which process data is stuffed where (data field) into which message (message identifier) and when this message is triggered. Typical message trigger events can be a detection in the change-of-state of the process data or a repetitive timer (e.g. transmit every 100ms).

If all nodes know their configuration upon startup, a "full-blown" master / configurator is not required to be present in the network, allowing for minimized implementations.

In addition, most of the communication functions in CANopen® are specified as "optional". This means that a specific device does only need to implement the functions it utilizes, greatly contributing to an application-optimized implementation.

In order to be able to easily exchange nodes from different manufacturers, CANopen® nodes need to be further standardized. So called Device Profiles specify the expected communication behavior for a particular application. A number of Device Profiles are available and new ones are constantly added. Existing Device Profiles cover generic I/O modules, encoders, inclinometer, drives and many other devices.

To get some hands-on experience, simply download the CANopen® simulation environment CANopen Magic ProDS Eval from www.CANopenMagic.com.

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