High-accuracy feedback of angular motion, compact dimensions, non-contact (frictionless) operation and resistance to contamination — despite having an optical grating — are said to be the main benefits of the new ECA 4000 absolute ring encoder range from Burgess Hill-based Heidenhain (GB) Ltd (
www.heidenhain.co.uk).
These units, which join the long-established ERA 4000 incremental ring encoder models, provide a direct upgrade path: the ECA variants offer 60% smaller position error and 45% faster operation. Typical applications are controlling the position of swivelling heads, spindles and rotary tables on tool and gear grinders, machining centres and CNC lathes. The units can also be used to control robots.
Owing to the ECA 4000’s wide mounting tolerances, it is said to be easy and quick to assemble to the host equipment. Each ring employs a three-point method that allows the installer to align the centres of the encoder drum and machine bearing in just a couple of minutes.
ECA 4000 encoders are available in a range of external drum diameters, from 104 to 560mm. Internal diameters range from 70 to 512mm, so that designers can pass cabling and other services through the centre to help streamline the machine.
Each ring size has a unique line count around the outside, up to 44,000 in the case of the largest model, for which an accuracy of ±1.5arc-sec is specified for the twin-track graduations. Each ring offers resolutions
better than 0.01arc-sec, while fast reaction times — even at speeds up to 2,500rev/min — make the encoders suitable for use with direct-drive motors.