IE38 Hollow Shaft Incremental Rotary Encoder 12-24V 100-1000PPR

IE38 Hollow Shaft Incremental Optical Rotary Encoder — Precision Pulse Sensing for Industrial Automation

The IE38 Hollow Shaft Incremental Rotary Encoder delivers reliable AB two-phase quadrature pulse output for precise measurement of rotational speed, angle, position, and linear displacement. Designed for industrial-grade automation applications, this compact 38mm body encoder operates on a wide DC 12–24V supply and is compatible with PLCs, microcontrollers, and motion-control systems right out of the box.

Key Features

• AB Two-Phase Quadrature Output: Direction-recognizable counting pulse signal generated via rotating optical grating disc and optocoupler technology for accurate bi-directional sensing.
• Wide PPR Selection: Available in 100, 200, 360, 400, 500, 600, and 1000 pulses per revolution (PPR) to suit a broad range of measurement requirements.
• Multiple Bore Sizes: Accommodates shaft diameters of 5mm, 6mm, and 8mm — select the bore that fits your application.
• Wide Voltage Input: DC 12–24V supply voltage for versatile integration into industrial and DIY automation setups.
• NPN Open-Collector Output: Directly interfaces with PLCs (NPN input mode, common connected to 0V) and microcontrollers with internal pull-up resistors — no additional circuitry needed in most setups.
• Maximum Mechanical Speed: Up to 1,000 RPM for dynamic motion measurement tasks.
• Compact & Lightweight: 38mm encoder body with small footprint makes installation straightforward in tight spaces.
• 1.5m Shielded Cable: Pre-wired with a 1.5-meter shielded cable (Red: +V, Black: GND, White: A-phase, Green: B-phase, Mesh: Shield) for quick, clean wiring.
• CE Certified: Meets CE certification standards for use in professional and industrial environments.

Technical Specifications

Typical Applications

• Rotational speed and angle measurement in industrial machinery
• Automatic length measurement and cutting control systems
• Automatic filling and dispensing machines
• Steel bar length-fixing and cutting controllers
• Height and position sensing instruments
• Robotics platforms and university/competition robots
• CNC, conveyor, and servo motor feedback systems

Wiring Guide

• Red — Positive supply (+V)
• Black — Negative / Ground (GND)
• White — A-phase output
• Green — B-phase output
• Mesh/Shield — Shielding (connect to ground at one end)

Note: Always verify wiring against the product nameplate label before powering on. Incorrect wiring may damage internal circuitry. Use an elastic/flexible coupling — do not rigidly connect the encoder shaft. Keep encoder output wires routed separately from power lines to avoid signal interference.

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Frequently Asked Questions

Q: What is the difference between NPN and PNP output on this rotary encoder, and which should I choose?

A: This IE38 encoder uses NPN open-collector output, meaning the output transistor pulls the signal line LOW when active. This is the most common type for PLC input modules wired in NPN (sinking) mode, where the common terminal is connected to 0V. If your PLC or controller uses PNP (sourcing) inputs, you will need to ensure the correct variant is selected at purchase. When in doubt, check your PLC's input specifications for the required input type.

Q: Why is there no signal visible on my oscilloscope when I connect the encoder?

A: The NPN open-collector output requires an external pull-up resistor (typically 1kΩ–10kΩ to the supply voltage) on each output line (A and B) before a voltage signal can be read by an oscilloscope. Most PLCs and microcontrollers have internal pull-up resistors, so this is only necessary for direct oscilloscope measurement or for controllers without internal pull-ups. Add one pull-up resistor per output phase and the signal will display correctly.

Q: Can I use this encoder for both speed and direction detection?

A: Yes. The AB two-phase quadrature output allows your controller to determine both the speed (from pulse frequency) and the direction of rotation (from the phase relationship between the A and B signals — A leads B for one direction and B leads A for the other). This makes the IE38 suitable for closed-loop motion control, position tracking, and bi-directional displacement measurement.

Q: What bore size and PPR should I select for my application?

A: Choose the bore size (5mm, 6mm, or 8mm) that matches your shaft diameter. For PPR, higher values (e.g. 600 or 1000 PPR) provide finer resolution and are better for precise position or length measurement; lower values (e.g. 100 or 200 PPR) are sufficient for basic speed sensing and are easier to process at high RPM. Always use an elastic/flexible coupling between the encoder and the shaft to protect the encoder bearings and extend service life.