MR324 Hollow Shaft Encoder

MR382-2 Sensor
September 17, 2015
MR320 and MR30X System Series
August 29, 2018

MR324 Hollow Shaft Encoder


ZapFREE® Hollow Shaft Fiber Optic Incremental Encoder

The MR324 ZapFREE® Heavy Duty Hollow Shaft 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 MR320 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.

 ZapFree  NEC  


Measurement Parameters
Resolution 1024ppr
Max Speed

2,500 RPM (All MR320 functions activated)

3,000 RPM continuous (MR320 Quadrature Outputs and Analog Outputs activated ONLY)

3,300 RPM short term (< 1 minute, MR320 Quadrature Outputs ONLY)

(NOTE: At 3,000 RPM, MR324 housing temperature rises by 25°C above ambient due to bearing friction. Environmental temperature must be reduced accordingly. There is also a tradeoff between operating speed and use of the MR320 Auxiliary fucntions (analog outputs, divider, multiplier, etc.) Contact Micronor to discuss your requirements..

Mechanical Parameters
Moment of Inertia 2.06E-4 kg*m. (Pocket Hole version), 2.09E-4 kg*m. (Through Hole version)
Starting Torque 3.53E-3 N*m (Pocket Hole version)
System MTBF L10 Bearing life calculated at 2500 RPM: 2.12E+07 hours (2411 years)
Optical Interface
Optical Interface LC Duplex, 62.5/125μm Graded Index Fiber, 0.275NA, Type OM1
Link Length Up to 2500 meters with MR320 Controller
Explosive Atmospheres Inherently Safe, Simple Mechanical Device
EX Classification

Inherently safe, simple mechanical device when used with MR320 Controller

IECEx Test Report (ExTR) GB/CML/ExTR  16.0039/00

EX EPL Mb/Gb/Gc/Db/Dc
NEC Exempt
Environmental Attributes

Standard: -40°C to +80°C, 0%-95% RH (non-condensing)

Extended: -60°C to +150°C, 0%-95% RH (non-condensing)

Ingress Protection

Through Hole Version=IP54 (dust protected, protected against splashing water)

Pocket Hole Version=IP66 (dust proof, protected against powerful water jets)

Physical Attributes
Housing Dimension Ø 100mm x 49mm
Unit Weight 655 g (23 oz)
Materials Body: Anodized Aluminum; Shaft Clamp 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” electronics-based encoders
  • Outdistances copper, link lengths to 2500m
  • Standard Temperature range: -40°C to +80°C;
  • Extended Temperature option: -60°C to +150°C
  • Special versions can be engineered for radiation and thermal-vac environments


Call 805.389.6600

Ordering Information