CANopen in selvedge weaving machine
Source: CAN Newsletter March 2008
By Kurt Hockemeyer (Gebr. Klöcker)
The CANstepper by Klöcker is a mechatronical actuator that consists of a rotary drive unit with computing power and with built-in complex electronics including CAN. The drive has proven its performance and long term stability in applications in the textile industry, where lightweight fibers and needles have to be moved at high speeds under extreme environmental conditions, i. e. vibrations, dust and 24 hours/7days-operation. A special application, for example, is its usage as a leno device on weaving machines for selvedge binding of the woven fabric implemented according to CiA 414. profile. The drive provides high dynamic positioning capability of tiny parts. For instance, up to 30 half turns per second with correspondingly alternating rotation reversals can be carried out, depending on the connected inertia. This feature makes the drive a suitable front end module in applications, where the focus is on high-speed positioning of little masses by a small number of angular degrees, rather than large torques, a huge number of rotations or extreme accuracy in positioning. Consequently, for multiple small power drive applications in distributed systems, this drive unit fills the gap between ordinary magnets (cheap and fast, but limited stroke only) and servo motors (too complex and powerful, and cost intense). The drive features up to 10 W average and 30 W peak electrical power input.
All electronic components, including micro-controller, non-volatile memory and motor drivers etc. as well as firmware necessary for operation and open-loop control of the stepper motor are integrated into the housing using SMD technology on flexible printed circuit boards. No separate control box is needed, for a minimum configuration 24 VDC and a CAN network have to be supplied only. According to the CAN specification, many drives can be operated on the same network. They are connected with each other just by a cable. Two 9-pin Sub-D connectors (male/female) support the linear topology of the CAN network.
