Adafruit customer service forums • View topic - Stepper motor leads
You can read our famous Step Motor Basics Guide all on one page here or skip to any .. of this as “friction heating” as the magnetic dipoles in the iron switch back and forth. The relationship between restoring torque and shaft error angle is. The relationship between phase (groups of coils) and polarity for the code below for how our simple one turns forward one turn backward. Definition of stepper - an electric motor or other device which moves or rotates in a series of small discrete steps., a portable block used in step aerob.
Swapping A1 with A2 or B1 with B2 in the above diagrams just reverses the direction of the motor. Swapping both will leave the direction unchanged. You have the option of using the two coils for each phase in parallel or in series. When using them in parallel, you decrease coil inductance, which can lead to increased performance if you have the ability to deliver more current.
However, since the Tic actively limits the output current per phase, you will only get half the phase current flowing through each of the two parallel coils. We generally recommend using a series connection. The following diagram shows how to connect such a stepper motor to the Tic with each pair of phase coils in parallel left or series right: Configuring and testing the stepper motor This section explains how to configure and test your motor over USB using the Tic Control Center software.
It is a good idea to test the motor over USB like this to make sure that the motor is working and that you can get the desired performance out of it before you connect a different kind of input to the Tic and try to use that to control the motor.
This screenshot shows the default settings for the Tic T The default motor settings for the Tic T Setting the current limit Assuming that you are not limited by the Tic or your power supply, we recommend setting the current limit of the Tic to the rated current of your motor. The current limit is specified in the Tic Control Center in units of milliamps mAwhich are one thousandth of an amp ampere. So if you want to set your current limit to 0.
Note that the current limit can only be set to certain specific values. After you type in a current limit, the control center will use the closest valid setting that is less than or equal to the current limit you typed. You can use the up and down arrows to browse through the valid current limit settings.
The different Tic models have different sets of allowed current limits. Press Resume to start. The Tic will detect that VIN has dropped too low 7. If this is happening in your system, what you will see is that the Tic drives the motor briefly and then switches back to the previous state, where the motor is de-energized because of a safe start violation.He Keeps Going Back And Forth With The Relationship. What Do I Do?
If your power supply voltage is around 2. An inadequate power supply can also cause other problems, such as disrupting the USB communication or making the Tic reset. If your system is having problems like this, you should try getting a better power supply or lowering the current limit to address these issues before continuing. You should make sure that your stepper motor can turn in both directions. If the stepper motor is not moving correctly, you should turn off your motor power, check all of your connections and soldering joints, if applicableand try again.
Checking the heat After you have gotten your motor to move, you might want to let the motor hold position for a while to see how hot the motor and the Tic get. Unlike a DC motor, stepper motors consume power and generate heat while they are not moving.
After your system heats up and reaches a steady state, if the motor or the Tic are hotter than you would like them to be, you might consider lowering the current limit. Allowed coil current transitions in full step mode.
Arrows to the right correspond to one motor rotation direction and arrows to the left correspond to the other. Another way to visualize this is with a graph of the coil currents for each of the four full steps, with one axis representing the phase or coil A current and the other axis representing the phase B current: Coil currents for the four 4 steps that make up full-step mode I In the other available step modes, the Tic uses microsteps instead of full steps to generate magnetic fields that point to places between the full steps.
In the above graph, currents I3, I7, I11, and I15 match the four full-step currents, where the magnitude of the current through both coils is equal. All other steps point between these full steps by setting different current limits for the two coils. The most extreme example of this occurs on steps I1, I5, I9, and I13, where the current through one coil is equal to the full current limit setting on the Tic while the current through the other coil is zero.
Therefore, if you change the step mode, you might have to change those other settings to account for the change. For example, the default maximum speed for the Tic is pulses per second.
Step Motor Basics | Geckodrive
If you change the step mode from full step to half step, you would have to change the speed to pulses per second to maintain the same angular rate of change. Since the step mode affects those other parameters, it is a good idea to set it first. Setting the decay mode T and T only The Tic T and Tic T have a decay mode setting that affects how fast current through the motor coils decays during each step.
The Tic T has three decay modes: The Tic T has five decay modes: The decay mode matters most when microstepping is used. Generally, using slow decay generates less electrical and audible noise, but it can result in missed microsteps when the coil current is decreasing.
Fast decay is much noisier both electrically and audibly, but it creates more evenly sized microsteps. Mixed decay is a combination of both fast and slow decay that tries to minimize noise while keeping microsteps as even as possible. Most motors have a maximum starting speed around pps or so. So in most cases you can start the motor at a higher speed than the resonant speed.
If you have to start at a speed below the resonant speed, accelerate through the resonant range quickly. Another solution is to make the step angle smaller.
The motor will always overshoot and undershoot more for bigger step angles. If the motor doesn't have to travel far, it will not build up enough force torque to overshoot a large amount. Anytime the step angle is made smaller, the motor will not vibrate as much. This is why half-stepping and microstepping systems are so effective at reducing vibration. Make sure the motor is sized properly to the load. By choosing the proper motor you can improve performance. Dampers are also available.
Dampers fit on the back shaft of a motor and absorb some of the vibrational energy. They'll often smooth out a vibrating motor inexpensively.
Tic Stepper Motor Controller User’s Guide
The most obvious difference between 2-phase and 5-phase see interactive diagram below is the number of stator poles. While 2-phase motors have 8 poles, 4 per phase, the 5-phase motor has 10 poles, 2 per phase. The rotor is the same as that of a 2-phase motor. Since the pitch is still 7. Simply based on construction, the resolution of the 5-phase has steps per revolution versus the 2-phase with steps per revolution.
The 5-phase offers a resolution 2. With a higher resolution you get a smaller step angle, which in turn reduces vibration. Since the step angle of the 5-phase is 2. In both 2-phase and 5-phase, the rotor must overshoot or undershoot more than 3.
Because the step angle of the 5-phase is only 0. The chances of losing synchronism with a 5-phase stepper motor are very low.
Drive Methods There are four different drive methods for stepper motors: In the wave drive method also called the 1-phase ON methodonly one phase is turned on at a time. When we energize the A phase a a south pole, it attracts the north pole of the rotor. Each time only one phase is energized. The wave drive has a four step electrical sequence to rotate the motor.
If both phases A and B are energized as south poles, the north pole of the rotor will be equally attracted to both poles and line up directly in the middle. In sequence as the phases are energized, the rotor will rotate to line up between the two energized poles. The "2 phase on" method has a four step electrical sequence to rotate the motor. What advantage does the "2 phase on" method have over the "1 phase on" method?
The answer is torque. In the "1 phase on" method, only one phase is turned on at a time, so we have one unit of torque acting on the rotor. In the "2 phase on" method, we have two units of torque acting on the rotor, 1 at the 12 o'clock position and 1 at the 3 o'clock position.
Five phase motors are a bit different.
Rather than using the "two phase on" method, we use the "four phase on" method. Each time we turn on 4 of the phases and the motor takes a step.
The five phase motor goes through a 10 step electrical sequence. In this case, we energize the A phase. The rotor lines up. At this point we keep the A phase on and energize the B phase.
Now the rotor is equally attracted to both an lines up in the middle. Now we turn off phase A but leave on phase B. The motor makes another step. And so on and so forth. By alternating between one phase on and two phases on, we have cut the step angle in half. Remember that with a smaller step angle, the vibration is reduced. For a 5-phase motor, we alternate between 4 phases and 5 phases on. The half step mode has an eight step electrical sequence.