A company of Schneider Electric

How They Work
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Scale
Newall's scale consists of high-precision nickel-chrome ball bearings inserted into a stainless steel (Sphersoyn™/SHG) or carbon fiber (Microsyn™/MHG) tube. The ball bearings are then pre-loaded against a traceable standard in a temperature-controlled environment.

Linear Encoder
The linear encoder is made up of a series of coil assemblies along with the supporting electronics. After final assembly the reader head cavity is filled with an epoxy resin to fully encapsulate and protect the electronic circuitry.

Linear Encoder Overview
The recent advancements of Digital Signal Processors (DSPs) alongside high-speed analogue to digital conversion ICs has allowed the Spherosyn™ technology (Download Technology Guide - 975k) to provide feedback for a wide range of signal protocols. This allows all Newall encoders to carry an IP67 (NEMA 6) environmental rating and will continue to provide accurate and reliable readings even when fully submersed in water, oil or coolant. No other linear encoder can equal the durability and reliability of the Newall encoders. Newall encoders can interface with all major CNC, NC, PLC and PC products.

• IP67 rating (NEMA Type 6)
• Withstands dust, dirt, oil and other harsh environmental conditions
• No mechanical wear characteristics
• Requires no cleaning or maintenance
• High tolerance to shock and vibration

Incremental Encoders
Newall Incremental linear encoders provide sine-cosine or quadrature square wave feedback signals that allow for direct integration to servo driven applications.

Newall encoders are based upon Spherosyn™ technology and operate on the principle of electromagnetic induction. Inducing a 10kHz sinusoidal current through a single drive coil within the reader head generates an electromagnetic field. This field interacts with the nickel chrome elements contained in the scale.

A set of four pickup coils detect variations in the induced field that are then combined and processed by the electronic circuitry to generate a signal that varies as the head moves along the scale. Depending on the position of the reader head as it passes over each element, the phase shift of this pickup signal relative to the drive signal will vary between 0 and 360 degrees. A high-speed digital-signal processor (DSP) converts the analogue signal to an industry standard differential quadrature signal. The DSP also generates the periodic reference marker pulse.

Absolute Encoders
Newall Absolute linear encoders provide a true absolute position immediately upon power-up. The encoder does not use batteries or static memory to retain the positional data. True position can be reacquired once power is applied, regardless of duration or power-off movements.

The scale is comprised of a stainless steel tube that houses a column of precision nickel-chrome elements. Coded inserts are placed between the elements in such a manner as not to interfere with the geometry of the system contact.

The aluminum cast reader head contains a coil assembly, the supporting electronics and a sensor array that detects the target that is embedded in the coded scale inserts. The cavity of the reader head is filled with an epoxy resin that fully seals the electronics and thus provides an IP67 rating. A high-speed Digital-Signal-Processor (DSP) is utilized in order to process the positional data and to communicate the output protocols.

Distance Coded Encoders
Newall Distance Coded linear encoder reference markers allow the controller to acquire absolute position by moving the encoder systems across two uniquely spaced reference markers.

By using its internal absolute position count the encoder can mimic the Distance Coded index marks that are generated by glass scales. An index pulse is generated at uniquely spaced intervals in the range of 4 to 10mm, varying by 20-micron increments. As the system is not constrained by any hardware limitations it can calculate and output almost any sequence of marker pulses.