The CBD (Communication Board DeviceNet) facilitates communication between SIMOREG converters and higher-level programmable controllers or other field devices by means of the DeviceNet protocol. The CBD board is inserted in the electronics box of the SIMOREG 6RA70 unit using the LBA and ADB adapter boards.

The CBD board supports the transfer of process data and parameter data using “DeviceNet Explicit Messages” and “DeviceNet I/O Messages”.

With DeviceNet, Explicit Message Connections provide generic, multi-use communication paths between two units. This allows typical requirements-oriented or response-oriented functions (e.g. board configuration) to be implemented.

In contrast, DeviceNet I/O Message Connections provide communication paths for special purposes between the transmitting and receiving units. Application-specific I/O data are transferred via an I/O connection. The significance of the data within an “I/O message” is determined by the associated “Connection ID”. The DeviceNet alarms can be subdivided into three main groups:

• DeviceNet configuration data, e.g. channel assignment, timeouts and I/O configurations, whereby “Explicit messages” are used
• Process data, e.g. control words, setpoint/reference values, status information and actual values, whereby “I/O messages” are used
• Parameter data for reading/writing drive parameter data, whereby manufacturer-specific PKW objects and “Explicit messages” are used.

The drive is controlled by process data (e.g. ctivation/deactivation and setpoint input). The number of process data words (4, 8 or 16) is either determined on switch-on by the value of certain CB parameters or dynamically by DeviceNet. The purpose for which the individual process data words are used is determined in the drive and differs in accordance with the actual function of each individual drive. The process data are processed with the highest priority and shortest time segments. The master uses the manufacturer-specific PKW object for the purpose of reading drive parameters with DeviceNet or modifying them, whereby the Explicit Messaging Channel is used. The user therefore has access to all parameters in the basic unit (CU) and any existing technology board (TB) via DeviceNet. Examples for this include read-out of detailed diagnostic information, error messages, etc. In this manner, additional information for drive monitoring could be requested from a higher-level system (e.g. a PC) without affecting the transmission of process data.

Control and operation of SIMOREG 6RA70 converters over DeviceNet

In the process data area, all the information is transferred that is necessary for controlling a drive within a specific technical process. The control information (control words) and setpoints are sent to the drive from the DeviceNet master. Information about the status of the drive (status words) as well as actual values are transferred in the opposite direction. The CBD communication board saves the received process data in the Dual-Port RAM in the order in which they were transferred in the message frame. An address is assigned to each word in the Dual-Port RAM. The content of the Dual-Port RAM in the drive (CU and, if necessary, TB) can be freely assigned by setting parameters. It can, for example, be specified that the second word in the process data area of the message frame should be used as a speed setpoint for the ramp-function generator follow-up. The same mechanism also applies for other setpoints and for each individual control word bit. This mechanism also applies for data exchange in the opposite direction when actual values and status words are transferred to the master. Diagnostic LEDs provide the user with information quickly about the current status of the CBD. More detailed diagnostic information can be read directly out of the diagnostics memory of the CBD with the help of a diagnostic parameter.

The CBD board operates with the “Predefined master/slave connection set”, that is defined in the DeviceNet specification. Both “Poll” and “Bit strobe” I/O messages are supported.

The CBD complies with the “DeviceNet Device Profile for Communication Adapters” (Device Type 12). This profile was selected to ensure that all features and extended functions of the SIMOREG 6RA70 converter can be used be the DeviceNet master. For the same reason, the CBD board has not implemented the “DeviceNet DC Drives” profile.