Siemens PLC originally controlled the stepper driver in this way

Stepper motors are often used for positioning control . It can control the angle of rotation (relatively speaking, distance) by the number of pulses output by the PLC , and the frequency of the pulses controls the rotation speed of the stepper motor. However, it is simple, economical and convenient to use in occasions where the control accuracy is not very high; for occasions that require high control accuracy, a servo control system must be used.
Stepping system = stepping driver + stepping motor. The stepper motor is driven by a stepper driver, which is equivalent to a drive power supply , and it is controlled by an external pulse signal and direction signal (here is an example of Siemens PLC output pulse), and then controls the rotation angle and speed of the stepper motor.

Step driver + step motor + Siemens PLC (CPU 222 CN)

related definition

1. Driver: The medium used for PLC to control the stepping motor, responsible for amplifying the pulse signal given by the PLC, and then transmitting it to the stepping motor, so that the motor operates according to the parameters given by the PLC and the driver.

control process

2. Step angle: The angle at which each pulse causes the stepper motor to rotate. The most common one is 1.8°. This generally cannot be changed.
Example: Without setting the subdivision, how many pulses does the PLC need to send out to control a stepper motor with a step angle of 1.8° to rotate one revolution (360°)?
360°/X=1.8°/1, so X=200 pulses.
3. Subdivision: In practical applications, it is found that if the step angle is large, the angle of each rotation will be large, which will cause vibration and the corresponding control error will also become larger. Therefore, the segmentation function was introduced. This means that the step angle can be increased by a few minutes through the driver’s DIP switch to make the motor rotate more smoothly.
Example: The step angle is 1.8°, and 10 subdivisions are set. Then every time the PLC sends out a pulse, the motor only rotates 0.18°, and the stepper motor rotates once (360°). How many pulses does the PLC need to send out?
360°/X=0.18°/1, so X=2000 pulses.
Summary: The larger the step angle, the fewer the number of pulses; the smaller the step angle, the more the number of pulses.

Introduction to stepping system hardware (taking Pfield stepper motor as an example)

1. Stepper driver

Pfield Drive Instructions

There are generally two types of direction control for stepper motors:

A) Pulse + direction: When PUL generates a pulse, the motor will rotate, and the direction is determined by DIR.

B) Forward pulse + reverse pulse: When PUL has a pulse, it will run forward; when DIR has a pulse, it will run anyway. However, PUL and DIR cannot generate pulses at the same time.

2. Stepper motor

Stepper motor parameters

When the AB two-phase windings are exchanged, the motor can be reversed.

Wiring diagram with PLC

The signal voltage of the stepper motor is 5V, and the voltage used by Siemens PLC is 24V, so to connect to the driver, a 1.2K, 1/4W resistor needs to be connected in series, as shown in the red part of the picture above.
Siemens PLC (CPU222) can output two types of high-speed pulses:
1. PTO (duty cycle 50%)
2. PWM (duty cycle can be changed)
The above two high-speed pulse output instructions can be used to control the stepper driver, and then the stepper motor, and then control the movement and speed of some specific equipment.

Siemens PLC originally controlled the stepper driver in this way

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