CiA® 446: CANopen device profile for AS-Interface gateways

The CiA 446 profile defines the CANopen interface for gateways connecting Actuator Sensor Interface (AS-Interface, here ASI) circuits. The gateway implements single or double ASI-controllers functionality with one or two ASI-circuits controlling up to 62 ASI-devices each. The actually valid CiA 446 v. 1.0.0 is based on the AS-Interface specification v. 3.0 released in 2004. The latter is also required for interpretation of CiA 446. When implementing the profile, ASI-gateway manufacturers may supply diverse application fields using the same electronic CANopen interface implementation and simply adapting the required functionality. A system designer may choose between ASI-to-CANopen gateway devices from different manufacturers implementing the same profile-compliant functionality. Off-the-shelf CANopen tools may be used for development, analysis, and maintenance purposes.
The profile specifies five classes of single/double ASI-controllers ranging from an M0 ASI single controller (controls up to 31 ASI-devices) to an M4 ASI double controller (controls up to 124 ASI-devices). Depending on the supported controller functionality up to eight TPDOs and RPDOs are pre-defined.
The application objects include digital and analog inputs as well as digital and analog outputs for up to 124 ASI-devices in two circuits. Each analog input and output has four 16-bit channels presented as four Integer16 values. The specified ASI-controller flags inform about the possible signal periphery or power failures, configuration status, automatic addressing functionality, as well as about the modes (e.g. normal, off-line) of the controller. The ASI-controller control word allows switching the controller into a certain mode (on-line, off-line, configuration, protected run-time), storing actual configuration, enabling/disabling automatic addressing, and data exchange. The according ASI-controller status word shows weather the required commands were executed correctly. Further, optional lists of active ASI-devices, detected ASI-devices, and of peripheral faults are provided. A possibility to write and to read a list of projected ASI-devices is given. Reading actual ASI-device configurations (e.g. ID code, I/O configuration) as well as writing and reading the permanent ASI-device configuration may be done via appropriate objects. Additionally, the information may be acyclically read/written from/to each ASI-device. The read/write response is then available on the CANopen network via specified objects.
For devices compliant to the profile it is recommended to use connectors and pinning assignment according to CiA 106. The physical layer definitions follow those in CiA 301. For node-ID assignment via the CANopen interface (e. g. for IP67-rated devices), it is recommended to use the CANopen layer setting services (see CiA 305). Support of the emergency message and the heartbeat functionality is mandatory.