Driver for unipolar stepper motor
The Unipolar Stepper Motor Driver block represents a driver specifically configured for use with the Unipolar Stepper Motor block. It connects the two winding center-tap connections A0 and B0 to the positive supply with a voltage equal to the value you provide for the Output voltage amplitude parameter. The A+, A-, B+, and B- ports are grounded in the appropriate sequence to create the stepping motion. The block initiates a step each time the voltage at the PWM port rises above the Enable threshold voltage parameter value.
If the voltage at the REV port is less than or equal to the Reverse threshold voltage parameter value, pulse A leads pulse B by 90 degrees. If the voltage at the REV port is greater than the Reverse threshold voltage value, pulse B leads pulse A by 90 degrees and the motor direction is reversed.
At time zero, A- and B+ are grounded.
If you set the Stepping mode parameter to Half stepping, the Unipolar Stepper Motor Driver block can produce the output waveforms required for half stepping. In this mode, there is an intermediate state between the full steps, in which just one of the A or the B half-windings is powered. As a result, the step size is half of the stepper motor's full step size. At half steps, windings that are not powered are short-circuited. This approximates the effect of a freewheeling diode connected across the windings.
When the voltage at the PWM port rises above this threshold, the Unipolar Stepper Motor Driver block initiates a step. The default value is 2.5 V.
When the voltage at the REV port rises above this threshold, pulse B leads pulse A by 90 degrees, and the motor direction is reversed. The default value is 2.5 V.
Amplitude of the output pulse trains. The default value is 10 V.
Select Full stepping or Half stepping. The default value is Full stepping.
The block has the following ports:
Top A-phase electrical connection
A-phase center tap connection
Lower A-phase electrical connection
Top B-phase electrical connection
B-phase center tap connection
Lower B-phase electrical connection
Triggering input step voltage
Input floating reference voltage
Input voltage that controls motor direction