Motion control: Absolute and ‘turbo fast’ motor feedback system
Sick Stegmann Inc. introduces the TTK70 motor feedback system, an absolute, non-contact linear measuring system that delivers measuring lengths up to 4,000 mm, resolution of <1μm and system accuracy of <10 μm, at operating speeds up to 10 m/s. The result is precise and highly reliable absolute position determination for linear motors in a diverse range of applications, according to the company.
TTK70 consists of a read head and a magnetic tape featuring a magnetic code that forms the measuring scale – 10 mm wide, and up to 4,000 mm long. The code consists of an incremental and an absolute track (twin-track tape). Absolute position values are calculated by the read head by first detecting the absolute starting position during start-up of the linear motor. All further positions of the drive are determined via the incremental position on the magnetic track, i.e. sine/cosine signals. The values are transmitted via the Hiperface interface to the evaluation electronics of the linear drive – a market-standard method of communication that is available for the first time for linear measurement, according the company. The result is an interface standard for all common servo drives, that covers all applications, with only one signal type.
The metal housing of the read head provides IP-65 protection, has two mounting holes designed for high tightening torques and even with the plug connection is hardly bigger than a matchbox. Inside, the TTK70 features the sensor PCB, aligned with the measuring plane and equipped with Hall sensors on two parallel tracks. When installed, their placement coincides with the position of an incremental and an absolute track on the magnetic tape.
"The development of the TTK70 is a direct result of the market trend towards increased use of direct drives, and its magnetic principle of operation offers clear advantages over optical linear systems in terms of price, susceptibility to contamination and overall reliability," says William Shatto, application engineer.
Sick-Stegmann is a wholly owned subsidiary of SICK AG in Waldkirch, Germany. The company offers drive manufacturers both rotary and linear motor feedback systems with an integrated Hiperface interface, which is popular in applications such as erosion machines, handling systems in semiconductor production, automatic assembly and placement machines, vertical lifting systems, pick-and-place applications in electronic production, and elsewhere.
– Edited by Renee Robbins, senior editor
Control Engineering News Desk