Quadrature Output Dual Channel Speed Sensors – HD Series

The HD series quadrature output sensors are based on Hall Effect sensor technology, which can sense a change in target motion from true zero to 15 KHz. The HD series offers dual channel output and, where required, directional logic. The output frequency of HD sensors has a square pulse waveform (digital) that directly relates to the number of turbine blades, gear teeth, etc. that have been sensed. These pulses, in turn, can be correlated to determine flow rate, RPM, or velocity.

HD sensors are based on the H series which incorporate a magnet within the sensor, enabling them to sense ferrous metal as well as magnet targets. Maximum air gap sensing distances are typically 0.100″ and these sensors can be optimized to detect fine as well as large pitch targets.

General Operation

The HD series sensors consist of two hall-effect elements biased with a magnet to detect the change in magnetic field strength caused by the rotation of a ferrous target gear. When the target gear passes by sensor element A, the output switches from a logic 0 to a logic 1 at half the pitch (P/2) of the target gear. As the target gear continues, the output switches from a logic 1 to a logic 0 at the gear pitch (P).

Sensor element B is placed at a distance of one fourth of the pitch of the target gear (P/4) from element A. The output of element B is shifted by one forth (P/4) from the output of element A. In electrical terms, this creates a phase shift of 90°. When the gear turns in the counterclockwise direction, output A leads output B. When the gear turns in the clockwise direction, output A lags output B.

The descriptions above are only a theoretical ideal model to explain the fundamental operation of the HD series sensors. The realities of the physical world such as mechanical tolerances, magnetic field variations, and other physical phenomenon cause deviations from the ideal model. Visit our Practical Application Guide to learn more.

Input Power
  • 4.7 to 24 VDC regulated, 15 mA maximum @ no load
  • Reverse polarity protected
Open Collector Type Output Options
  • TTL/CMOS (Standard): fan-out of 5 TTL/CMOS loads
         – VOL < 0.4V
         – VOH > VOUT X (RLOAD / (RLOAD+1000)
  • Open Collector
  • Supply tracking
         -VOL < 0.4V
         – VOH > (VSUPPLY – 0.2) X (RLOAD / (RLOAD+1000)

Push-Pull Type Output Options

  • Push-Pull Fixed Voltage
         – VOL < 0.4V @ 30mA
         – VOH > VOUT – 0.4V @ -30mA
  • Push-Pull Supply Tracking
         – VOL < 0.4V @ 30mA
         – VOH > VSUP – 0.6V @ -30mA
  • Differential Push-Pull, Fixed or Supply Tracking

Up to 0.100″ dependent on target geometry, magnet construction and sensor construction (for those based on the H series)

Interconnection Options

  • Pigtail with wires or cable
  • NPT threaded body with wire or cable pigtail for explosion proof environments
  • Connector per customer specifications

Unconditional one (1) year warranty if used within specifications

Physical Features

  • Operating temperature:
    -40°C to +125°C

    Units that operate up to +150°C are also available
  • Storage temperature:
    -40°C to +150°C
  • Body material: 300 series stainless steel
  • Encapsulation: epoxy potting or hermetically sealed, welded construction
  • High Shock and Vibration Resistance – contact factory for details


  • Alignment of the sensor to target rotation is required for optimal performance, ensuring proper orientation of the hall effect element to the magnetic field
  • Our Quadrature sensors are aligned and tested with a 12 pitch gear. The alignment mark on the sensor housing is based upon the 12 pitch gear. In the event that a gear with a different pitch is used, the alignment mark should only be used as a starting point and the sensor should be rotated during installation while monitoring the output in order to obtain the proper Quadrature signal. If the proper alignment marking for use with a different pitch gear is desired, please contact the sales department with gear details prior to ordering.
CE compliant to EMC Directive 2004/108/EC for use in residential, commercial, light industrial and heavy industrial environments

Open CollectorSupply TrackingHD-116Flange MountConnector
Open CollectorSupply TrackingHD-117Flange MountCable
Open CollectorSupply TrackingHD-1185/8-18 ThreadCable
Open Collector5VHD-119Flange MountConnector
Open Collector5VHD-120Flange MountCable
Open Collector5VHD-1215/8-18 ThreadCable
Open CollectorIsolated, Supply TrackingHD-122Flange MountConnector
Open CollectorIsolated, Supply TrackingHD-123Flange MountCable
Open CollectorIsolated, Supply TrackingHD-1245/8-18 ThreadCable
Open CollectorIsolated, 5VHD-125Flange MountConnector
Open CollectorIsolated, 5VHD-126Flange MountCable
Open CollectorIsolated, 5VHD-1275/8-18 ThreadCable
Open CollectorSupply Tracking, DirectionHD-128Flange MountConnector
Open CollectorSupply Tracking, DirectionHD-129Flange MountCable
Open CollectorSupply Tracking, DirectionHD-1305/8-18 ThreadCable
Open Collector5V, DirectionHD-131Flange MountConnector
Open Collector5V, DirectionHD-132Flange MountCable
Open Collector5V, DirectionHD-1335/8-18 ThreadCable
Open CollectorNoneHD-67Flange MountConnector
Open CollectorNoneHD-134Flange MountCable
Open CollectorNoneHD-1355/8-18 ThreadCable
Open CollectorDirectionHD-136Flange MountConnector
Open CollectorDirectionHD-137Flange MountCable
Open CollectorDirectionHD-1385/8-18 ThreadCable
Push/PullSupply TrackingHD-139Flange MountConnector
Push/PullSupply TrackingHD-140Flange MountCable
Push/PullSupply TrackingHD-1415/8-18 ThreadCable
Push/Pull5VHD-142Flange MountConnector
Push/Pull5VHD-143Flange MountCable
Push/Pull5VHD-1445/8-18 ThreadCable
Push/PullDifferential, Supply TrackingHD-145Flange MountConnector
Push/PullDifferential, Supply TrackingHD-146Flange MountCable
Push/PullDifferential, Supply TrackingHD-1475/8-18 ThreadCable
Push/PullDifferential, 5VHD-148Flange MountConnector
Push/PullDifferential, 5VHD-149Flange MountCable
Push/PullDifferential, 5VHD-1505/8-18 ThreadCable
Push/PullSupply Tracking, DirectionHD-151Flange MountConnector
Push/PullSupply Tracking, DirectionHD-152Flange MountCable
Push/PullSupply Tracking, DirectionHD-1535/8-18 ThreadCable
Push/Pull5V, DirectionHD-154Flange MountConnector
Push/Pull5V, DirectionHD-155Flange MountCable
Push/Pull5V, DirectionHD-1565/8-18 ThreadCable
Push/PullIsolated, Supply TrackingHD-157Flange MountConnector
Push/PullIsolated, Supply TrackingHD-158Flange MountCable
Push/PullIsolated, Supply TrackingHD-1595/8-18 ThreadCable

Dimensions in inches
Specifications +/-10%
Mounting threads UNF-2A

hall effect speed sensor