Incremental Encoder Signal Converter

What are the functions of an Incremental Encoder Signal Converter?

An Incremental encoder is an electro-mechanical device that converts angular motion or relative position of a shaft into digital or pulse signals by employing an optical disk. Incremental encoders can be used in positioning and motor speed feedback applications. See below for more information about how incremental encoders work.

An Incremental Encoder Signal Converter converts the pulses from an incremental encoder into analog or digital formats. It is an essential device for reading and processing the output from the encoder.  

FUTEK’s USB520 Incremental Encoder Signal Converter is able to process quadrature leading and lagging pulses, with speed measurement up to 150,000 pulses per second and angle measurement up to 10,000 pulses per rotation. The encoder data is read up to 10 Hz, or 10 samples per second. 

Additionally, signal converters (aka amplifiers), modulate electrical signals and are capable of performing the following signal conditioning steps:

Excitation Voltage

Some sensors require an excitation voltage to feed the Wheatstone bridge and generate their output signal as a ratio of the input excitation voltage. Thus, you need to establish if your DAQ or PLC can support the sensor’s input voltage or excitation voltage requirements. Simply put, an unstable excitation voltage input leads to an unstable sensor output. In case you need an amplifier module for PLC or DAQ and they do not provide a stable input excitation voltage, the amplifier will be the excitation voltage source to ensure the sensor provides a reliable and consistent output signal.


Analog sensor signals are susceptible to electrical noise and/or residual ripple voltage, which can distort or skew measurements. Noise needs to be filtered out before you can capture an accurate signal. DAQs and PLCs designed to interface directly with full-bridge sensors will include pass band and other forms of signal conditioning and filtration. In a low noise signal conditioner, electronic filters eliminate some effects on accuracy by removing electrical noise and ripple effect above and below the analog sensor’s signal range, resulting in a low signal-to-noise ratio.


Sensors can output a signal in the nanovolt through millivolt range. When your DAQ or PLC is limited to measuring volts, you will need an amplifier to convert millivolts to a larger signal. Some PLCs and DAQs come with built-in amplification; others will require an external amplifier. What if your existing DAQ or PLC does not provide built-in amplification, signal conditioning, and a stable power source for sensor excitation? In that case, you will need an amplifier to fill in the shortfalls in your instrumentation.

The USB integration works hand in hand with SENSIT Test and Measurement software, which allows users to monitor the actual output of the sensor in real-time. FUTEK developed DLL Libraries to allow USB520 to also work with other software such as LabView® and Visual Studio.

USB520 Features

  • Supports Encoder Input: Quadrature Leading and Lagging Pulse
  • USB 2.0 Communication Link;
  • USB Bus-Powered (5V);
  • Input/Output Short Circuit Protection;
  • Streaming ASCII Output;
  • Offered with DLL/Mac Dynamic Library;
  • CE Approved Class A (required for Medical and Aerospace applications);
  • Industrial metallic enclosure;
  • Integrated DIN rail mount;
  • Supports, VDC, mA, mV and TTL type input.


incremental encoder signal converter


Sampling Rate Up to 4800 SPS
Bandwidth (Hz) Sampling Rate (SPS) / 4
Internal Resolution 24 bits
Resolution (Noise Free) See Chart on Page 3
Non Linearity (max) ± 0.005% of FSR
Output Digital Packetized Data
Integrated Digital Filter 50 Hz/60 Hz Rejection (100 dB)
On Chip Memory 1 Kilobyte
Stored Calibration Up to 16 Points
Weight 0.43 lb (195 g)
On Chip Sensor Profiles Up to 4
ASCII Output Update Rate 10 SPS
IP Rating IP50
Encoder Input Quadrature Leading and Lagging Pulse (TTL type)
Speed Measurement Up to 150k Pulses Per Second¹
Angle Measurement (α) Up to 10k Pulses Per Rotation (PPR)¹
Angle/Speed Measurement (Update Rate) 100 ms
Bridge Excitation 4.6 VDC
Standard Input Range ± 3.4 mV/V (factory default)
Optional Input Range Up to ± 400 mV/V
Min. Bridge Resistance 50 Ohm
Max. Bridge Resistance 5000 Ohm
Supply Voltage Selectable 5,9,10,12,15,18,20,24 VDC/1W
Standard Input Range ± 10 VDC (Factory Default)
Supply Voltage Selectable 5,9,10,12,15,18,20,24 VDC/1W
Standard Input Range 0-20 mA (Factory Default)
Sensor Connector Binder 09 0132 90 12
Mating Connector Binder 99 5129 00 12
USB 2.0 Connector Type B
¹ Speed = ∆ α × 60 / PPR  
Operating Temperature -13°F to 185°F [-25°C to 85°C]
Storage Temperature -40°F to 257°F [-40°C to 125°C]
RoHS 2011/65/EU
CE EN61326-1:2013; EN55011:2009
(Amended by A1:2010)
5 18 20.5
50 16.5 19.5
100 16.3 19.2
300 15.8 18.2
1200 14.6 17.0
2400 13.6 16.0
4800 13.6 16.0

What is an Incremental Encoder?

An Incremental encoder is an electro-mechanical device that converts the angular motion or relative position of a shaft into digital or pulse signals employing an optical disk. Incremental encoders are commonly used in rotary encoders.

This device consists of a rotating disk, a light-emitting source, and light-receiving elements (photosensor). The disk, which is mounted on the rotating shaft, has patterns of opaque and transparent sectors coded into the disk. As the disk rotates, these patterns block the light emitted onto the photodetector, generating a digital or pulse signal output, also known as quadrature pulse signal.

Incremental encoders provide rotational or angular speed. They can measure the change in position, but not the absolute position of the shaft. Since there are few constructive elements involved, it is a relatively simple and inexpensive transducer.

Commonly, the incremental encoder uses two output channels (A and B) to detect angular position. Using two code tracks with sectors positioned 90° out of phase, the two output channels of the quadrature encoder indicate both position and direction of rotation. If A leads B, for example, the disk is rotating in a clockwise direction (i.e. quadrature leading pulse). If B leads A, then the disk is rotating in a counter-clockwise direction (i.e. quadrature lagging pulse). Therefore, by monitoring both the number of pulses and the relative phase of signals A and B, you can track both the relative position and direction of rotation.

Advantages of Incremental Encoders

  • Typically lower cost relative to absolute encoders;
  • Good for simple pulse counting or frequency monitoring applications such as speed, direction, and position monitoring;
  • Less complex than absolute encoders;
  • High noise immunity.
incremental encoder signal converter