Two phase stepper motor introduction:
The actual stepper motor control is very simple, the application are fools, manufacturers do a good job of stepper motor driver, stepper motor how to work by the driver to control, we do not need to do an in-depth understanding of the stepper motor, as long as you know the application of the stepper motor driver method can be. Of course the simple stepper motor operating characteristics, or must know, I will introduce below!
The role of subdivision:
Two-phase stepper motor, the basic step angle of 1.8 degrees, that is: 200 pulses motor turn a circle, called the whole step.
The function of the subdivision can be set on the driver of the stepper motor:
When set to 2 subdivisions (also called half-steps), the step angle is 0.9 degrees, 400 pulses turn a circle.
When set to 4 subdivisions, the step angle is 0.45 degrees and 800 pulses go around.
When set to 8 subdivision, the step angle is 0.225 degrees and 1600 pulses go around.
The higher the subdivision, the smaller the length of a pulse sent by the host computer, the higher the precision! This is well understood, a pulse to go 10 mm, 10% error, a pulse error of 1 mm, a pulse to go 1 mm, the same 10% error, a pulse error of 0.1 mm.
Of course, we can not set the fine fraction very large, to achieve the purpose of each pulse to walk a particularly small length.
You remember the two-phase stepper motor 200 pulses to turn a circle on the line! The larger the subdivision, the larger the number of pulses for one revolution of the stepper motor!
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If we want the stepper to travel 400 mm at 600 revolutions per minute, how do we calculate the number of pulses and the pulse frequency that the OP needs to send out?
How do we control the speed of the stepper motor (i.e., how do we calculate the pulse frequency):
Assuming that the setting is four fine fractions, the number of pulses required for the motor to make one revolution, i.e., 800, to achieve a stepper motor speed of 600 rpm, the calculation of the frequency of pulses that should be sent by the host computer:
The concept of frequency is the number of pulses sent in one second.
So, first calculate the number of revolutions per second of the stepper motor
600/60 = 10 revolutions per second
Then calculate the number of pulses needed for 10 revolutions/sec.
10 X 800 = 8000
That is, the pulse frequency is 8000, or 8K.
Conclusion, in order to realize the stepper motor speed of 600 rpm, the host computer should maintain a pulse output frequency of 8K.
Now do you understand? In order to calculate the pulse frequency must know the two prerequisites are:
1, know the number of pulses required for one revolution of the stepper motor;
2, know the rotational speed of the stepper motor, the rotational speed unit is: revolutions per
How to calculate the number of pulses required by a stepper motor.
Assuming that the setting is four fine fractions, the number of pulses required for the motor to turn a circle is 800, and to realize that the stepper motor travels a distance of 400 mm, the calculation of the number of pulses that should be sent by the upper computer:
If the output shaft of the stepper motor and screw (pitch: 10mm) direct connection, or through the pulley drive, wheel circumference of 10mm. That is, the stepper motor to turn a circle, the length of the mechanical walking 10mm.
The number of pulses of one revolution of the motor is 800, then the length of a pulse walking:
10mm / 800 = 0.0125 mm
The number of pulses required to travel 400mm:
400 / 0.0125 = 32000 pulses
Conclusion, in order to realize a distance of 400 mm traveled by the stepper motor, the number of pulses that should be sent by the host computer is 32000.
Do you understand now? The three prerequisites that must be known in order to calculate the number of pulses are:
1, know the number of pulses required for one revolution of the stepper motor;
2, know the stepper motor to turn a circle of the walking length;
3, know the total length of travel required by the stepper motor;
If we want to improve the accuracy, we can increase the subdivision, if the subdivision is set to 64 The number of pulses required for one revolution of the motor is:
64 X 200 = 12800
The length of a pulse traveled is:
10mm / 12800 = 0.00078 mm
The number of pulses required to travel 400 mm:
400 / 0.00078 = 512000 pulses
To achieve a speed of 600 rpm, the frequency of pulses that should be sent by the host computer is:
( 600 / 60 ) X 12800 = 128000
That is: 128K
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Post time: Aug-11-2024
