CANopen-based system controls crochet looms
Source: CAN Newsletter June 2011
The control system for the crochet looms by Comez, situated in Cilavegna, Italy, has been developed by the Italian CMZ electronic systems in Treviso. This company is specialized in designing CAN-based control systems for the textile machine industry. The already realized projects range from the first treatment of cotton fiber (or other fibers) to the final stages such as stitching and embroidering tissue. The flexibility of the controller architecture has enabled the controller provider to use the same system for other types of machines, for example for Jacquard looms.
The crochet loom essentially produces bands, laces, dress fabrics and technical fabrics, trimmings, and fringes. In terms of electronics in the system there is a host controller managing up to 32 actuators of various types. Each actuator consists of a brushless motor with integrated smart-drive. Most common is the actuator that drives the bars back and forth synchronously with the advantange of the product read by a machine encoder.
The band is divided into several lines that describe the drawing to be implemented. In each line the actuators must have a specific position. The value of the encoder identifies the line of the drawing, each line is divided into two phases: a ”data updating phase” (during which actuators receive information about position to take) and a ”movement phase”. Another type of actuator is the type ”gearing” that moves in gearing with the machine encoder with a ratio that may vary in each line.
At the maximum speed of the machine the duration of each phase is 15 ms. The connection between the host controller and actuators is done through a CAN network. The host controller provides NMT master functionality. It also performs the supervision of the network and the transmission of parameters to the actuators, which are intelligent nodes compliant to the CiA 301 (CANopen).
