Miniature drives seldom work alone in automated systems. Most have to work in tandem with another drive, and that means they must offer simple networking. Many drives simply use either RS-232 or CAN, the controller-area-network protocol. So brushless dc motors coupled with integrated control electronics using CAN or RS-232 interfaces appear destined for a wide range of automation jobs.
The Faulhaber 3564 BC Series of motors from MicroMo Electronics is typical of this new connectivity and control paradigm. The 80 50 40-mm unit contains a 3 electronically commutated dc motor with a high-resolution encoder and programmable positioning and velocity control electronics. Digital signal processing reduces scan times to 100 msec, resulting in motor response times of less than 500 msec.
Control is either through an RS-232 interface at 115 kbps, which provides trace functions every 3 msec, or via CANopen with trace functions to 1 msec. Trace functions let monitoring software track drive operations through its network connection. Addressable interfaces on each motor eliminate multiplexer boards. Drives connect in a daisy-chain arrangement with other drives. Programs and control parameters are saved directly in the drive using a compression format. No data is lost during power failures. The drive is ready to run as soon as power returns.
Many small motors connect directly to CANopen networks using CiA's drive profiles. Automatic data-rate detection and parameter setting over the network simplifies the task of connecting these small drives.
MicroMo Electronics Inc.