Application Note
February 2016
Controlling a Stepper Motor
with SpTool
1. Introduction:
A stepper motor is a brushless DC electric motor that
divides a full rotation into a number of equal steps. The
motor's position can then be commanded to move and hold
at one of these steps without any feedback sensor (an openloop controller), as long as the motor is carefully sized to the
application in respect to torque and speed.
There are two basic winding arrangements for the
electromagnetic coils in a two phase stepper motor: bipolar
and unipolar.
With SpCard and SpTool you can control both, unipolar and bipolar motors.
Before making any connection, be aware about the specification of your motor. As a
rule bipolar motor has 4 wires and stepper motors with 5 or 6 wires can be connected
as bipolar or unipolar depending of the connections. Once you have choose the type of
motor you want to use it will be quite easy to configure the control with SpTool.
2. User Guide:
a. Open SpTool: you will see a configuration window like this. Choose Motors,
Stepper and add it in the desired Pin.
b. The application has 6 different modes: choose the one you desire for your
motor. The first three modes allows you to move the motor permanently and
the last three ones allows you to select the number of steps. In the following
boxes you can select the speed in HZ (pulses per second), the number of steps
(just in case the mode allows it), the direction and the state (on/off).
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Buck Synchronous
Note: different modes such as Wavedrive, Full-Step and Half-Step differ in the type
of control that implements. You can see the different waveform in the next image.
As a rule Wavedrive and Full-Step give the
double of speed than Half-Step, but Half-Step give the
double of torque and double of steps (more precision).
c. The speed of your motor depend on the number of poles, the reduction of the
specific motor and the mode selected:
angular velocity =
speed(Hz)
𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑜𝑙𝑒𝑠 ∗ 𝑟𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 ∗ 2𝑘
k=0.5 in Wavedrive and full-step modes.
K=1 in half-step mode.

For example a motor in full-step mode with 4 poles and without reduction will spin
100 rounds each second if you choose 400 Hz of speed. In case your motor has a
reduction of 50 it will spin 2 rounds per second.

The number of degrees per round depend on the number of poles the mode and the
reduction of the motor also. For example, a motor in full-step with 4 poles and without
reduction will give 4 steps each round (90 grades per step). The same motor with
reduction of 64 will give 256 steps per round (1.4 grades per step).
For more information contact with:
Developed by: Gonzalo Salinas gonzalo.salinas@spcontroltechnologies.com
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