MR304 Encoder

MR304 Fiber Optic Incremental Encoder




ZapFREE® Size 11 Incremental Rotary Encoder

The MR304 Mini Rotary Encoder is a Size 11, small form factor incremental encoder offering resolution to 512ppr. It is intermountable with resolvers, synchros and conventional electronics-based encoders of the same size.

The MR304 Encoder is a 100% passive sensor which operates entirely in the optical domain. The sensor provides immunity to any electro-magnetic interferences such as lightning, radiation, magnetic fields and other harsh environment conditions. The innovative design provides 100% electrical isolation as well as immunity to high voltages – ideal for harsh environment applications such as feedback for welding robots, measuring anode position in smelters, and monitoring pantograph operation in electric rail applications.



Resolution 256, 360, 512ppr
Maximum Speed 10,000 RPM, Mechanical Limit
Optical Interface
Connector LC Duplex
Fiber Duplex 62.5/125μm Graded Index Fiber, 0.27NA, Type OM-1
Maximum Distance Up to 2000 meters with MR302 series Controller
Explosive Atmospheres Inherently Safe, Simple Mechanical Device
EX Classification Inherently Safe. Simple Mechanical Device when used with the MR302 Controller
IECEx Test Report (ExTR) GB/CML/ExTR 16.0039/00
IEC Ex EPL Mb/Gb/Gc/Db/Dc
NEC Exempt
Temperature -40°C to +80°C (-40°F to +176°F), 0-95% RH, Non-Condensing
Ingress Protection IP40
Physical Attributes
Dimensions Ø25 mm x 50.9 mm (Ø0.98 x 2.00 inches)
Weight 55 g (1.94 oz)
Materials Anodized aluminum housing, SS shaft, SS bearings

Specifications subject to change without notice



  • Medical
  • MRI
  • Robotics
  • Industrial
  • Transportation
  • Oil & Gas


  • 100% passive optical sensor
  • Size 11 small form factor
  • Up to 512ppr resolution
  • Immune to EMI, RFI, lightning and ground loops
  • Immune to magnetic fields
  • Inherently safe, Simple Mechanical Device
  • Fiber optic link can extend up to 2000 meters
  • DIN rail mount and OEM PCB controller available


  • 0.5-meter circumference
  • Tufted rubber coating
  • For textile, bare metals and varnished surfaces
  • For use with 8400.00.020 Arm and Clamping Flange-style 58mm Encoder with 10mm OD shaft




Call +1-805-389-6600 or email

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