Incremental rotary encoder | Optical | HB5M

  • Hollow bore (hollow shaft / thru-bore) bearing design
  • Rugged anodized aluminum housing
  • Heavy duty ball bearings track up to 6,000 RPM
  • Positive latching polarized connector
  • 2-channel quadrature, TTL squarewave outputs
  • 3rd channel index option
  • Differential line driver output option
  • 32 to 5,000 cycles per revolution (CPR)
  • 128 to 20,000 pulses per revolution (PPR)
Manufacturer:US Digital


The HB5M is a hollow bore (hollow shaft / thru-bore) optical encoder with a machined aluminum enclosure and an anodized protective finish. The HB5M optical incremental encoder is designed to easily mount to an existing shaft to provide digital feedback information. Typical applications include motor feedback, process control, robotics, textile machines and elevator controls.

The HB5M bearing style encoder features a hollow bore that accepts shaft diameters from 5mm to 8mm in diameter. The encoder slips over the shaft and is locked into place with two 4-48 set screws. A flexible anti-rotation mount makes the encoder more tolerant of shaft runout than a standard kit encoder. The HB5M can accommodate shaft runout up to 0.030" axial and 0.010 in. radial. The flexible tether provides mounting for two 4-40 machine screws on a 1.812" bolt circle.

The HB5M housing comes standard with a closed cover or an optional hole in the body to allow a shaft to pass completely through the encoder.

The differential version has an internal differential line driver (26C31) that can source and sink 20mA at TTL levels. The cable that connects to this encoder should have 3 twisted pairs for the data channels plus power and ground. The recommended receiver is the industry standard 26C32.

The mating connector is polarized and latches into the encoder. Depressing the latch tab allows the connector to be unplugged. Mating connector assemblies are available from US Digital. Custom cables are also readily available (see the Cables / Connectors page).

Attribute NameAttribute Value
Documentation from Manufacturer
Output Signal Type
Measuring Principle
Pulse count - max. (ppr)
Not specified
Housing Diameter (mm)
Shaft Type
Shaft Diameter (mm)
5, 6, 1/4'', 5/16", 8
Revolutions - max. (rpm)
Protection Rating Housing
Not specified
Connector, Cable
Housing Material



Sweden, Solna, Signalistgatan 14, 16972.

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