ServoWire is ... flexible

IEEE-1394 provides technology to guarantee delivery of real-time servo information each loop update.

The second type of data transfer supported in 1394, asynchronous communications, provides a mechanism for flexibly managing real-time command and status communications on the network.

 Upon completion of all isochronous transfers in each loop update, the remaining bandwidth is available for asynchronous transfers. Asynchronous communications can be used to:

• enable or disable the drive
• dynamically adjust tuning parameters
• modify drive setup
• monitor system variables in real-time
• transfer diagnostic messages and reset errors
• and more.

Many applications can benefit from the ability to adjust system parameters under software control while the servos are operating. One example is adjusting system inertia while motor loads vary in a winding/unwinding operation. The variable INERTIA@ is used by MotionBASIC to let an application program adjust servo loop variables as the roll diameter changes. Dynamically setting servo loop parameters based on roll diameter and tension "on-the-fly" provides repeatable performance and consistent operation over a wide range of operating conditions.

This approach allows high-performance servo systems to handle the combination of large roll diameter changes and load-to-motor inertia mismatches, that can be as large as 1,000 to 1 in high performance winding applications.