MR303 Linear Encoder

ZapFree   MR  


 ZapFREE® MRI Safe Linear Incremental Sensor

 The MR303 series fiber optic linear position sensor is an innovative all-optical, passive design which is immune to any electro-magnetic interferences such as magnetic fields, lightning and high voltages. Its non-metallic construction makes the sensor entirely MRI safe, being both immune and invisible to magnetic fields.

In operation, the MR303 Linear Position Sensor is optically connected to an MR302 Controller via a duplex multimode fiber optic link. An incremental film strip passes through the optical pick-up and the phase offset of two light beams create the classical A/B quadrature signals accessible via the controller interface.

As an incremental system, the absolute position must be set every time the system is powered up. To automate this process, Micronor has developed a special “homing” zone left or right of the film’s active area. In operation, the mechanical system starts up in the “homing” zone and moves towards the first line in the active area. This corresponds to the reference or index position on a conventional encoder. As the sensor moves into the active area, the counter can correctly track the absolute position.


Measurement Parameters
Resolution 100 μm
Maximum Speed 40m/s (based on 100kHz controller bandwidth)
Optical Interface
Connector LC Duplex
Fiber Type Duplex 62.5/125μm, Graded Index Fiber, 0.27NA, Type OM-1
Maximum Distance Up to 2000 meters with MR302 series encoder
MR Attributes
MRI Usage Zones

Reference: ACR Guidance Document for Safe MR Practices 2007

MR303 sensor is designed for safe use in all MR Zones I-IV

Materials Used

Acetal, ceramic, glass (No ferromagnetic metal or conductive materials are used)

NOTE: The LC Duplex optical connector has some small metal parts. The pigtail length shall assure that the connector end is safely secured outside the MRI bore

Explosive Atmospheres
EX Classification Inherently safe, simple mechanical device when used with MR302 Controller
IEC Ex EPL Mb/Gb/Gc/Db/Dc
NEC Exempt
Environmental Attributes

Operating: -10°C to +60°C (14°F to +140°F), 0-95% RH, Non-Condensing

Storage: -25°C to +70°C (-13°F to +158°F), 0-95% RH, Non-Condensing

Ingress Protection IP30, Keep free from contaminants
Physical Attributes
Dimensions 30 x 28 x 15 mm (1.18 x 1.10 x 0.59 inches)
Weight (without cable) 10 g (0.3 oz), Cable weight ~10g/m

Specifications subject to change without notice


  • Medical
  • MRI
  • Robotics
  • Industrial


  • 100% passive optical sensor
  • 0.1 mm positional resolution
  • MRI safe design
  • Immune to EMI, RFI, lightning and ground loops
  • Immune and invisible to magnetic fields
  • Inherently Safe, Simple Mechanical Device
  • Fiber optic link can extend up to 2000 meters
  • DIN rail mount and OEM controller available


Call +1-805-389-6600 or email


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