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A suitable controller allows you to control the stepper motor, specifying the step and direction signals. What are the characteristics of such components?
What is a stepper motor?
Before we get to the description of the controller, it’s worth explaining what the driver itself is stepper motor. It is a mechanism included in the group of electric motors – its operation is based on the principle of pulsed electric power. The operation of the motor depends on the number of pulses at the input, as well as the frequency at which they are applied.
A standard 2-phase stepper motor consists of two key components:
- Rotor, or moving part of the motor – such as a permanent magnet;
- stator or stator – the stationary part on which the coils per phase are located in selected combinations.
The sequential power supply to the coils produces a voltage torque that puts the rotor into rotary motion, resulting in mechanical energy. Unlike motors that perform a constant rotational motion, stepper motors do not have mechanical-electrical components that work with a commutator to force current to flow in the corresponding parts of the rotor winding. Stepper motors are often compared to servo drives, which provide more positioning capabilities, but are more costly.
What is the principle of the stepper motor?
The main task of a stepper motor is to convert electrical energy into mechanical energy. Among the main features of components of this type, it is worth mentioning the precision of movement – the rotation of the rotor by a certain angle causes the controlled object to move by a proportional distance.
The motor’s rotor is set in motion by pulses generated in the control system, making it move a certain number of steps. The drive, however, comes from electromagnets, which, when voltage is applied, become the winding of the stationary part of the motor (stator).
What is a stepper motor controller?
Stepper motor controller is an important component of the motor that allows you to adjust its speed and direction. Its primary function is to power the phases of the stepper motor to achieve continuous motion. Since stepper motors move by taking a certain number of steps per shaft revolution, a component is needed to precisely control this movement – this is the controller.
All stepper motor controllers allow you to set both the current value and the step division. Depending on the model selected, the configuration options for the second of these parameters can range from 1 to as high as 1/512. The various solutions also differ in terms of the characteristics of the motors to which they can be connected – the most important issue here is the number of motor leads.
Stepper motor controller – how it works
The stepper motor controller is to generate the appropriate signal (step – “step”; or direction – “dir”) to move the motor axis. It is produced based on the input of these two values. In the case of the step signal, each pulse means that the motor takes one step, while the direction signal allows you to adjust the device’s path.
Stepper motor controller – types
We can roughly divide stepper motor controllers into two types – constant-voltage and constant-current devices. Their main difference is the value used to generate torque: in the first case it is voltage, and in the second – amperage. Constant-voltage controllers feature lower efficiency, which is combined with a lower price, while constant-current controllers are more expensive but offer greater efficiency. Specific models may also differ in current characteristics or recommended motor power (in the case of stepper motors – measured in the Nm unit). When buying a controller, you should also pay attention to the minimum, typical and maximum supply voltage, which will allow you to adjust the appropriate solution to the characteristics of the rest of the system.
Stepper motor and controller - application
Stepper motors – and therefore also their drivers – are devices that find application in many areas. However, they are primarily used where a way to accurately control movement is needed. Stepper motors can drive equipment such as:
- plotters – in devices of this type are used for precision cutting and drawing;
- 3D printers – Stepper motors are used to precisely position the print head;
- Industrial robots – to control the movement of individual parts of the machine;
- Electron microscopes and spectrometers, where stepper motors help move the objects under study accurately and safely.
How to select a stepper motor controller?
In order to choose the right controller for your system, you need to think first of all about the characteristics of the motor that will be operated by this equipment. The controller should be able to deliver power to the motor with the right value. Also of considerable importance is the current rating for the controller, which should not differ by more than 5% from the corresponding parameter in the motor itself.
It is also worth considering how the controller is configured. This process can take place, among other things. using software that can offer the ability to set additional parameters, such as the idle current function. Importantly, some controllers can only be used with a controller that generates step and directional signals, while others can be controlled using various communication protocols.
Botland store has in its offer numerous models of stepper motor controllers, which can be used in CNC equipment, small automation and robotics projects, measuring equipment and many other systems with various functionality. We provide reliable information on the parameters of each electrical component in our range, as well as access to an extensive knowledge base – welcome to the online store Botland.
