Encoders: Heavy duty magnetic rotary and tiny micro inductive models debut
Baumer introduces MHXX Series of magnetic rotary encoders, while Maxon Motor USA introduces the Mile inductive encoder for micromotors.
Encoders, also called transducers, encode position or orientation and convert it to a digital signal. With the Sensors Expo in full swing in Chicago, announcements of new encoder designs are everywhere. Two of many represent the range of options: Baumer has introduced the MHXX Series of hollow-shaft, large-bore, magnetic rotary encoders, while Maxon Motor USA has introduced the Mile encoder for micromotors, which it says is the world’s smallest inductive encoder.
For high resolution, high dynamic measurement of position, speed and velocity, Baumer’s MHXX Series magnetic rotary encoders can be used on equipment and machinery used in motion control, textile production, wood/timber processing, packaging, machine tool, medical, electric motor and general industrial applications.
These non-contact encoders contain no bearings, so measurement is contact-free and components do not wear. They feature very thin rotors and read heads that adapt easily to the axis of rotation and are specifically designed for use on shafts from 20 mm to 740 mm. The design allows large clearances between the rotor and the sensing head for easy mounting, and the encoder’s disk may be mounted using set-crews, clamping rings, or clamping fixtures.
Baumer's IP67-rated encoders withstand vibration to 30 g and shock to 300 g and operate efficiently in temperatures from -40issible air gap tolerance depending on size of bore.
Baumer makes a range of other sensors, encoders, and machine vision products, including tiny inductive sensors.
Maxon Motors USA is calling its new Mile encoder the smallest of its kind in the world: an inductive encoder with a diameter of 6mm where the contrast is generated with eddy currents. Typical areas of application are medical technology, robotics and industrial applications in harsh environments.
According to Maxon, the general basis of inductive encoders is that the inductance of one or more coils changes in relation to the material used. For example, a semi-circular iron core representing the material measure could be directed to a coil, which then changes its inductance. However, there are drawbacks to simple inductive encoders, such as the temperature dependence of the soft iron/ferrite. External magnetic fields can also change the permeability of the material used, well below saturation point, according to the company.
“This is why highly accurate inductive encoders are ironless,” said a spokesman.
“With the Mile encoder, the contrast is generated with eddy currents. These encoders have long been featured in large motors, but have not been produced for micromotors until now. Maxon Motor has invested heavily in the development of these greatly miniaturized inductive encoders.”
The Mile encoder delivers 64 pulses at up to 120,000 rpm, has 3 channels, line driver and integrated commutation outputs. The Mile also is available in combination with the company’s EC6 brushless DC motor, extending the length of the combination by only 1mm.
– Edited by Renee Robbins , senior editor
Control Engineering News Desk