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MR345 Rotary Incremental Encoder



ZapFree  NEC  


ZapFREE® Size 125mm Fiber Optic Incremental Encoder

The MR345 ZapFREE® Heavy Duty Fiber Optic Incremental Sensor is an entirely passive, intrinsically safe, fiber optic incremental rotary encoder – ideal for a wide range of harsh and hazardous environmental applications. The passive, all-optical sensor connects to the remote controller via a standard duplex 62.5/125 multimode optical fiber link.

The remote MR340 Controller Module transmits and converts optical signals to/from the sensor. The controller’s multiple built-in interfaces insure compatibility with industry standard motor drives, PLCs, quadrature counters and motion control systems.


Measurement Parameters  
Resolution 1024ppr
Max Speed 3600 RPM Continuous
Mechanical Parameters  
Rotor Moment of Inertia 6.65E-4 kg*m.
Starting Torque 1.79E-3 N*m
Max Shaft Loads Radial = 300N (67 lbf), Axial = 200N (22 lbf)
System MTBF L10 bearing life calculated at 50% of max radial and axial load at 3000 RPM:

1.128E+05 hours (12.9 years)

Optical Interface  
Optical Interface ODVA IP-LC Receptacle, 62.5/125μm Graded Index Fiber, 0.275NA, Type OM1
Link Length Up to 2000m (3280 ft). with MR320 Controller
Explosive Atmospheres Inherently Safe, Simple Mechanical Device
EX Classification Inherently safe, simple mechanical device when used with MR340 Controller
IECEx EPL Mb/Gb/Gc/Db/Dc
Environmental Attributes  
Temperature/Humidity Operating: 40°C to +80°C ; Storage : 40°C to +80°C, 0%-95% RH (non-condensing
Ingress Protection IP67 (temporary submersion)
Physical Attributes  
Housing Dimension Ø 125mm x 92mm
Unit Weight 1505 g (53 oz)
Materials Body: Anodized Aluminum; Shaft and Bearings: Stainless Steel

Specifications subject to change without notice


  • 100% passive sensing design – no electronics whatsoever
  • Sensor can be installed in all manner of hazardous locations and potentially explosive atmospheres – mines, gas and dust
  • Immune to EMI and RFI for safe use in and around medical equipment, VFD drives and other “noisy” industrial environments
  • Immune to lightning and high voltage which “zaps” electronic-based encoders
  • Outdistances copper, link lengths to 2000m
  • Temperature range -40°C to +80°C;
  • Special versions can be engineered for radiation and high temperature environments
  • Compatible with MR340-1 DIN Rail Mount Controller


Call +1-805-389-6600 or email

Ordering Information

MR345-F12D00 Size 125mm Encoder, 1024ppr, IP-LC Interface
MR340-1 DIN Rail Mount Controller

Quick Ship Configurations

MR340-0 DIN Rail Mount Controller
MR345-F12D00 Size 125mm Encoder, 1024ppr, IP66, IP-LC Interface

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