Electrical signals carry power and information with ease, but they sometimes have a problem with electromagnetic interference. Arcing is another concern, especially in flammable or explosive environments. For one encoder, the solution is simple: Don't use electrical signals, use light. Two-color light enters the encoder, passing through a slotted disk and a pair of filters. The light then reflects off a mirror, returning through the filters and disk — back into the fiber where it originated. An electronic module determines shaft angle and direction by counting pulses and measuring phase differences between the two wavelengths. Readings are in standard quadrature format at a resolution of 100 or 256pulse/rev, depending on the model.

VITAL STATS

On display: MR312 ZapFree Encoder

Key feature: Passive optical design

What it means to you: Eliminates arcing risks and EMI/RFI concerns

What else: Low power consumption (less than 50 mA from a 12 to 32-Vdc source); compact design; reliable to 6,000 rpm; -40 to 80°C temperature range (-60 to 150°C optional); programmable divider function; two programmable analog outputs (mA and V); serial interface for direct computer control.

Innovator: Micronor Inc., Newbury Park, Calif.

For more info: Call (805) 499-0114 or visit www.micronor.com.
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