What is servo control? A beginner’s guide

October 18, 2023
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What is a servo controller?

A servo controller is a device that governs the movement of a servo motor. But, hold on, let’s first describe a servo motor.

A servo motor is different from your typical motor. Imagine turning on a fan. It spins continuously until you shut it off. That's like a standard motor. While standard motors run continuously as long as they're powered, a servo motor’s movement is all about controlled positions. 

Think of a servo motor like a dial or a thermostat; you can set it to a specific point, and it stays there. Now, the servo controller is what tells the servo motor where to go and ensures it stops at the right spot.

So, in essence, the servo controller is the brain, giving directions, while the servo motor is the executor, following those directions to a T.

Components of a servo controller

Dismantling a servo controller might not be on your to-do list, but understanding its inner workings can be fascinating. There are three primary components that keep the servo controller ticking, and here's a breakdown of each:

1. Actuator: This is like the heart of the system. The actuator is responsible for the actual movement. Whether it's rotating an arm, pushing a lever, or any other mechanical action, it's the actuator that's doing the heavy lifting. It takes the command from the controller and translates it into physical motion.

2. Sensor: Think of this as the eyes and ears of the servo controller. The sensor continuously monitors the position of the actuator. This feedback is crucial because it tells the controller where the actuator currently is in comparison to where it should be. It's this constant loop of information that ensures the precision of a servo motor.

3. Control Circuit: If the actuator is the heart and the sensor is the eyes and ears, then the control circuit is undoubtedly the brain. It processes the information from the sensor, makes decisions based on that feedback, and then sends commands to the actuator. It ensures the actuator's movement aligns perfectly with the desired position.

To visualize this, imagine trying to park your car in a tight spot. The actuator is your car's engine, propelling it forward. The sensor is like your eyes, constantly judging the distance to the curb. And the control circuit? That's you, processing what you see and adjusting the gas or brake accordingly to park perfectly.

How does a servo controller work?

Here's a step-by-step breakdown of how servo controllers achieve their great precision:

  1. The servo controller gets a command to move the servo motor to a specific position. This could be from an operator, a computer, or any other control device.
  2. Once the command is received, the control circuit comes into play. It evaluates the current position of the motor (thanks to the feedback from the sensor) and determines the best way to achieve the desired position.
  3. Based on the decisions made by the control circuit, the actuator springs into action. It moves in the required direction to align with the desired position.
  4. While the actuator is on the move, the sensor doesn't take a break. It constantly sends feedback to the control circuit about the motor's current position.
  5. Based on the feedback, the control circuit might realize that the motor has moved a tad too far or not far enough. It then sends corrective commands to the actuator to make necessary adjustments, ensuring the motor reaches the exact desired spot.
  6. Once the motor is in the desired position, the servo controller ensures it stays put, resisting any external forces that might try to displace it.
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Benefits of using a servo controller

The growing popularity of servo controllers isn't mere hype. These devices have a lot of advantages that cater to the practical needs of many industries. Here's a rundown of why they're increasingly becoming the go-to choice:

Energy Efficiency: Unlike motors that run continuously, servo motors use power efficiently, especially under the guidance of their controllers. They consume energy only when moving and often revert to a low-power state when stationary. This translates to significant energy savings over extended periods.

Precision and Accuracy: We've touched on this before, but it's worth emphasizing. The continuous feedback loop between the sensor and the control circuit ensures the servo motor's movements are incredibly precise, achieving desired positions without overshooting or undershooting.

Versatility: One of the standout features of servo controllers is their adaptability. They can be fine-tuned to cater to a broad spectrum of tasks. Whether it's the rapid movements required in manufacturing or the gentle precision needed in medical applications, a servo controller can handle it.

Durability and Longevity: Servo controllers are designed for demanding environments. Their robust construction ensures they can handle rigorous usage without frequent breakdowns. Plus, their ability to operate without continuously running reduces wear and tear, ensuring a longer lifespan.

Compactness: Many modern servo controllers are designed to be compact, making them suitable for applications where space is a premium. This compact design doesn't compromise their performance, ensuring power-packed performance in a small footprint.

Enhanced Productivity: In an industrial setting, time is money. Servo controllers ensure operations are swift, reducing the time taken for tasks. This enhanced speed and efficiency can significantly boost productivity levels.

Practical tips if you are new to servo controllers

Here are some hands-on tips to guide you through the maze and ensure you get the most out of these devices:

  1. Before diving into the specifics of servo controllers, have a clear understanding of what you need. Are you aiming for ultra-precise movements, rapid operations, or perhaps both? Knowing your requirements will guide your choice.
  2. Consider your environment. Not all servo controllers are built the same. Some might be suitable for industrial environments, while others are tailored for cleaner, more controlled settings. Factor in temperature, potential contaminants, and other environmental conditions when selecting a servo controller.
  3. If you're retrofitting an existing system, check how seamlessly the servo controller integrates. Compatibility with your current hardware and software can save significant time and potential headaches down the road.
  4. Ensure connections are tight, components are clean, and software is updated. A well-maintained servo controller not only performs better but also has a longer lifespan.
  5. Ensure safety protocols are in place, especially if they're being used in environments with humans. Features like emergency stop controls and protective barriers can be invaluable.
  6. Ensure that everyone handling the servo controllers is adequately trained. Proper knowledge can prevent mishaps and ensure the devices are used to their fullest potential.


Servo controllers bridge the gap between human intention and mechanical execution, ensuring that tasks are carried out with meticulous attention to detail. As industries evolve and the push for greater efficiency grows stronger, the role of servo controllers is set to become even more pivotal. 

So, the next time you witness a robot making its precise moves or a conveyor belt running like clockwork, take a moment to appreciate the servo controller, working tirelessly behind the scenes.

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