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MR431-A06 MRI Safe POF Absolute Encoder





ZapFREE® Fiber Optic Absolute Position Sensor

The MR431 ZapFREE® Fiber Optic Absolute Position Sensor measures absolute angular position from 0° to 360° with 0.044° resolution.

This innovative sensor transceives -interference free- up to 30 meters. The system consists of a passive optical sensor (MR431) and active controller (MR430) linked via a duplex 1mm M-POF plastic optical fiber cable assembly (MR439).


Measurement Parameters
Measurement Range 0° to 360° (continuous)
Resolution 13 bits (8192), 0.044°
Accuracy 0.5°
Repeatability ±0.175°
Maximum RPM 500 RPM continuous, 2200 RPM intermittent Note: 2200 RPM for <2 seconds duration, in stop motion allowed
Mechanical Performance
Starting Torque 0.1 N*m with Shaft Seal
Max Shaft Loads 500g at 5mm distance
Optical Interface
Optical Interface Duplex, POF and M-POF
Link Length Up to 30meters (100 feet) with MR430 controller
Explosive Atmospheres Inherently Safe, Simple Mechanical Device
EX Classification Inherently safe, simple mechanical device when used with MR430-1 Controller IECEx Test Report (ExTR) TBD
IEC Ex EPL Mb/Gb/Gc/Db/Dc
MR Attributes ACR Guidance Document for Safe MR Practices
MRI Usage Zones MR431 sensor and MR439 cable assembly is designed for safe use in Zones I-IV
Materials MRI Safe, Non-metallic, Body/Shaft: Acetal
Environmental Performance
Sensor Temperature

Operating: -5°C to +55°C (+23°F to +131°F)

Storage: -40°C to +80°C (-40°F to +176°F)

Cable Temperature

Operating: -40°C to +60°C (-40°F to +140°F)

Storage: -40°C to +80°C (-40°F to +140°F)

Humidity 0%-95% (non-condensing)
Ingress Protection IP65
Physical Attributes
Housing Dimension Ø 25mm x 26mm x Ø 6mm Shaft
Unit Weight 15g (0.53 oz) without pigtail

Specifications subject to change without notice


  • 100% passive sensing design – no electronics whatsoever
  • Absolute 13-bit single-turn resolution
  • Sensor can be installed in all manner of hazardous location and explosive atmosphere – mines, gas and dust
  • Non-metallic and all optical design allows for use in MRI and Radiation applications.
  • Immune to EMI and RFI for safe use in and around medical equipment and “noisy” industrial environments
  • Immune to lightning and high voltages
  • Link lengths up to 30 meters
  • Standard model operates over -5°C to +55 °C (23°F to 131°F)


Call +1-805-389-6600 or email

Ordering Information

MR431-A06 Sensor with 6mm OD Shaft
MR431-1101 Set of 3x synchro clamps and screws
MR439-PXX M-POF Sensor Cables, where XX=length in meters:
05=5m, 10=10m, 20=20m
Contact Micronor sales for OEM custom lengths.

Quick Ship Configurations

MR430-1 DIN rail mount controller
MR430-99-01 SSI/RS485 Interface (J2) Pigtail Assembly, L=1m
MR431-A06 Sensor with 6mm OD Shaft
MR431-1101 Set of 3x synchro clamps and screws
MR439-P05 M-POF Sensor Cable, 5m
MR439-P10 M-POF Sensor Cable, 10m

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