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Passive encoder survives hostile environments

A Micronor product story
Edited by the Engineeringtalk editorial team Sep 13, 2004

The MR312 ZapFree incremental rotary encoder (patent pending) is the world's first commercially available, entirely passive encoder for rotation sensing applications.

The MR312 ZapFree incremental rotary encoder (patent pending) is the world's first commercially available, entirely passive encoder for rotation sensing applications.

There are no integral electronics within the encoder housing and the all-optical design requires just a single optical fibre connection, offering the utmost in simplicity, reliability and ease of installation.

The MR312 offers immunity to lightning and atmospheric static that would "zap" conventional encoders; outdistances copper cable by allowing link lengths to 1000m; its inert nature proves ideal for use in hazardous and explosive environments; and its intrinsic EMI/RFI resistance allows for safe and reliable operation in and around medical equipment and other "noisy" industrial environments.

ZapFree by Micronor represents the application of fibre optic technology in a novel and ingenious way to maximise sensor and transducer performance in a wide range of industrial, aerospace and other harsh environments.

Every ZapFree product embodies the fundamental advantages of using fibre optics - EMI/RFI resistance, passivity, light weight and the ability to transmit high datarates over extremely long distances.

The design of the MR312 rotary encoder goes one step further by using telecomms-proven WDM (wavelength division multiplexing) technology by assigning each internal optical path to a wavelength so that all wavelengths/paths can be combined onto a single fibre.

It was deliberate to avoid the use of multiple fibres as this tends to drive up the cost of the optical harness.

A single-fibre cable is inherently more cost effective than any multiwire or multifibre or hybrid cable assembly - and easier to handle and install as well.

It doesn't get any simpler.

Micronor offers the MR312 encoder and MR310 remote encoder interface (REI) as a turnkey solution with industry standard interfaces.

The MR312 is packaged in a standard Size 58 (58mm OD) encoder housing and mechanically interfaces to motors and shafts like conventional encoders.

The optical connection between the MR312 encoder and MR310 remote encoder interface (REI) module is via a single strand of industry standard 62.5/125 multimode optical cabling.

Downstream, the MR310 REI converts the optical quadrature signals to both industry standard open collector outputs (A, B) and line driver outputs (A, A', B, B') for ease of connection to a conventional counter, PLC or computer interface board.

The interface module is packaged in a standard 35mm DIN rail mountable module and draws a maximum 50mA from a readily available 12-32V DC power connection.

The MR312 is an ideal match for applications exposed to lightning, atmospheric static or plasma fields, such as found with aerial trams, ski lifts, wind turbine generators, radar/satellite antennas and semiconductor plasma-etching equipment.

It provides safe use in petrochemical processing plants and other hazardous/explosive environments.

The use of this product ensures reliable machine operation in the presence of electrical noise, RFI and other forms of interference found in and around industrial environments and heavy machinery, ie motors, brakes, clutches, smelters, and power transformers.

For nuclear power plant and space applications, the simple design allows for ease of engineering radiation hardened and space compliant versions.

Simplicity, design elegance and the ability to perform in a wide range of harsh environments are the hallmarks of the Micronor MR312 ZapFree incremental rotary encoder.

The product can operate over a wide temperature range, -40 to +80C, and an extended temperature option covers -60 to +150C.

The MR312 series is initially offered in 100 and 256pulse/rev configurations.

Although offered in a standard Size 58 package, the MR312 can be easily upsized or downsized for specific applications.

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