analog vs. digital servos

Analog vs. Digital Servos: Which Is the Better Option?

October 14, 2021

Servo motors control everything from the remote control cars of our youth to the CNC machines in your shop today. There are two main types of servo motors: analog and digital.

This article will compare analog vs. digital servos in depth. We'll go into all the differences between digital and analog servos and explore the best applications for each.

What Is a Servo Motor?

Whether you're talking about digital servos or analog servos, the basic definition is the same. A servo is an electronic device that precisely and accurately controls motion direction, velocity and torque. The main components of a servo include the:

  • Motor
  • Encoder
  • Driver
  • Potentiometer

A servo includes wires to the control signal and power source. It is controlled by a series of pulses.

What Is Pulse Width Modulation?

An understanding of analog and digital servos requires an understanding of pulse width modulation. PWM is a system that uses a series of electrical pulses of varying lengths to send a signal between two devices, such as a cell tower and phone, remote control and RC car or servo drive and motor.

PWM systems are essentially like a person flipping a switch on and off but at incredibly high speeds. The system may produce anywhere from 50 to hundreds of pulses per second, but when it doesn't send pulses, it's essentially turned off and no electricity leaves it.

What Is an Analog Servo?

Analog servos are the standard in many applications. An analog servo sends 50 or more pulses a second and shuts off in between. Because it offers very accurate control even when there are substantial changes in the load on the motor, an analog servo motor is often used when motion or velocity must be precisely controlled.

The advantages of analog servos include:

  • Easy setup and installation
  • Instantaneous updating (no microprocessor time)
  • Adaptability to form and factor
  • High bandwidth
  • Wide selection of choices

But they also have some disadvantages, mainly because they require manual tuning.

What Is a Digital Servo?

Digital servos use a high-powered microprocessor to produce hundreds of pulses per second. The microprocessor on a digital servo motor gives it some programming and intelligence capabilities. Other advantages include:

  • Easy configuration (no manual tuning required)
  • High power density
  • Precise fault indication — can transmit the reason for a fault
  • Flexible control type after configuration
  • Centralized or distributed network control

What Is the Difference Between Digital and Analog Servos?

When you discuss the differences of digital vs. analog servos, the main factors are:

  • Pulse rate
  • Output consistency
  • Power usage

Digital servos can send pulse signals at a rate at least five times faster than analog servos. As a result, digital servos offer a quicker and smoother output than analog servos, which often deliver sluggish torque.

On the downside, the higher pulse rate of a digital servo demands higher power consumption than required by an analog servo. A digital servo motor also tends to be more expensive than an analog one.

Analog vs. Digital Servos: Which to Choose?

While the function of analog vs. digital servos is basically the same, each is more appropriate for specific uses.

In most simple applications, analog servos will serve your purposes well enough. However, it's wise to invest in digital servos for more complex applications, such as advanced motion control or systems where you need to store sequences in the servo's memory.


Find Parts for Analog and Digital Servos at Industrial Automation Co.

Whether you use analog servos or digital servos, Industrial Automation Co. wants to make getting parts for your equipment as easy as driving a remote control car. We offer servo drive amplifiers for all major brands, including Mitsubishi and Allen-Bradley. You can count on our products for the reliability and durability you expect from an industry leader. Start shopping now and find the amplifiers you need.