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Catalogue Linear Encoder Brochure

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Linear Encoder Overview

Incremental

Newall Incremental encoders provide quadrature square wave or sine-cosine feedback signals that allow for direct integration to

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

A set of four pickup coils detect variations in the induced field which 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

Newall Absolute 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 re-acquired once power is applied, regardless of duration or

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 aluminium 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 utilised in order to process the positional data and to communicate the output protocols.

Distance-Coded

Newall's Distance-Coded Linear Encoder allows the controller to acquire an 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 encoder is not constrained by any hardware limitations it can calculate and output almost any sequence of marker pulses.

Company Profile

Newall, founded in Peterborough, England in 1968 and now a wholly owned subsidiary of BEI Technologies Inc., a Schneider Electric Company, has dedicated itself to providing the automation, machine tool and other machinery and production industries with leading edge technologies that increase productivity and machine tool efficiency.

In 1973, continuous design and development of Newall's technologies gave rise to the reliable and highly accurate Spherosyn™ and Microsyn™ Linear encoders. The range now also includes incremental and absolute versions, available with industry standard output signals which can be interfaced with all major CNC, NC, PLC and PC products.

The latest SHG and MHG Linear Encoders incorporate a truly unique design in that none of the electrical or measuring components are exposed to harsh workshop environments and they will continue to provide accurate and reliable readings even when fully submerged in water, oil or coolant. For this reason all of the Newall linear encoder range carry an IP67 (NEMA 6) environmental rating.

Newall's products range also includes a wide range of Digital readout systems; each specifically designed and dedicated to increasing machine productivity. The Digital Readout range has developed to become the most advanced readouts available today and combined with the Spherosyn™ and Microsyn™ technology encoders,is one of the reasons why the Newall range is a market leader.

Over 85% of its products are exported, with distribution and service outlets in over 63 countries. Newall actively supports these markets with a worldwide network of fully trained sales and service personnel. In addition offices are located in mainland Europe and the United States. Newall conforms to ISO 900 and, in 1998, it was awarded the prestigious Queen's Award for Export Achievement.

Linear Encoder Overview

The recent advancements of Digital Signal Processors (DSPs) alongside high-speed analogue to digital conversion ICs has allowed the Spherosyn® technology 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


TYPE	Incremental	Incremental	Incremental	Distance-Coded	Absolute
Product Group	SHG-T* & V*	MHG-T* & V*	MAG-TS	SHG-TC	SHG_A*
Protection	IP67	IP67	IP67	IP67	IP67
Accuracy Grade	±10	±5, 10	±25 + (20\|jm/m)	±3, 5, I0	±3,5, 10
Maximum Traverse Speed	2MHz (2m/s at lurn resolution)	2MHz (2m/s at lum resolution)	250KHz (4m/s at I0\|jm resolution)	8MHz (8m/s at lum resolution)	30m/s
Shock Vibration	100g (IEC 69-2-6) 30g (IEC 68-2-27)

NEWALL MEASUREMENT SYSTEMS BEI TECHNOLOGIES, INC. ³