Getting up and running with your Tic stepper motor controller from Pololu is
easy. This video will guide you through the basic steps to connect your Tic to
its software and control a stepper motor from your computer.
The first thing you should do once you receive your Tic is head on over to
pololu.com and navigate to the product page for your Tic. In this video, we're
using the assembled version of the Tic T825. On the product page, locate the resources.
Then open the user's guide in a new tab. Once you have the users guide
open, we recommend you familiarize yourself with its contents. It's
especially important to read the overview, installation instructions for
your operating system, the led feedback section, and the first
three sections for setting up your controller. Note that with any of the
users guides of pololu.com you can view the document as a printable PDF. You can
also view the document on a single page. This is especially useful if you'd like
to search the document for specific words.
Once you've looked over the users guide a bit, head to the getting started sub
section that contains the installation instructions for your operating system
and follow the steps listed there to download and install the Tic control
center software. Once you've installed the software, open it on your computer.
It's good practice to check things are working in small chunks rather than
doing your first checks after you've spent hours making a really complicated
system. With the Tics, and probably most USB products, it's especially easy to do
some basic checks before wiring or soldering anything up just by plugging
it into USB and confirming everything's working. You should start by running the
control center software and connecting the Tic to your computer. When you plug
in your Tic, the software might automatically connect to it but if it
doesn't you should be able to select your Tic from the connected to
drop-down box. Once the software is connected, the green LED should be
flickering indicating there is USB activity, and the red and yellow LEDs
should be solid and blinking respectively indicating that there is no
power supply to Vin, which is what we expect since we haven't connected power
for our motor yet. If your LEDs are doing something different,
refer to the LED feedback section of the users guide. If you can't connect to the
Tic, revisit the installation section of the user's guide. Make sure you follow
the instructions carefully and refer to the troubleshooting information to get
the Tic to connect. Now that you've confirmed the Tic is working you can
set up your controller with your stepper motor and power supply. If you haven't
already selected a power supply and stepper motor for your project you
should refer to section 4.1 of the user's guide.
For this video, we're using a three amp adjustable power supply set to 12 volts
and a NEMA 17 size stepper motor. This stepper motor and many others are
available on our website and can be found by searching for stepper motors
and selecting the category at the top of the search results.
Note that the NEMA designation is based solely on size, not electrical
characteristics. Any stepper motor with a 1.7 inch square face is considered NEMA 17
Other characteristics about the motor such as holding torque, voltage and
current ratings, and height vary within the NEMA 17 designation. Section 4.2 of
the users guide discusses how to connect your stepper motor and power supply to
your Tic. For our 4 wire bipolar stepper motor we need to connect one coil to the
A outputs on the Tic and the other coil to the B outputs.
By referring to the product page for our stepper motor, we know that the black and
green wires are one coil and the blue and red wires are another coil. So we
will connect the black wire to A1, the green wire to A2, the blue wire to B2,
and the red wire to B1. Note that if you happen to flip which way the wires are
connected for any coil, for example, swapping red and blue, the motor will
turn in the opposite direction. And if you happen to pair up wires for
different coils, the motor either won't go or should be noticeably erratic.
If you power up your Tic and realize you wired your stepper motor incorrectly
your Tic will probably be fine, but before fixing your connections be sure
to disconnect your input and USB power. Failing to turn off power while changing
connections is a gamble that can lead to your electronics breaking. Next, connect
your power supply to the GND and Vin pins on the high current side of the board.
Now you can connect the Tic to your computer. Before starting our
stepper motor we need to set the current limit. This is what enables us to use a
12 volt supply with a 2.8 volt stepper motor. As long as we set the current
limit to the stepper motor's rated current, we can use a 12 volt input.
From the stepper motors product page, we know our motors rated current is about 1.7A.
The Tic T825 can provide up to 1.5A without additional cooling,
and since we don't have a heatsink on our Tic or fan in our setup,
we'll set our current limit to 1.5A. In the Tic control center, select the input
and motor settings tab. The current limit setting can be found in the motor box
and is expressed in milliamps(mA). Enter your current limit. Note that even though 1500
was entered, the current limit setting is 1472mA. This is because the limit
can only be set in increments, so the control center will use the closest
valid setting that is less than or equal to the value you entered. Once you've set
the current limit click apply settings, and click the green resume button to
energize the stepper motor. If everything is working, the current you have selected
will start flowing through the coils and the message at the bottom of the
control center should say driving. Remember, even though the motor is not
moving there can be quite a bit of current flowing, so the Tic and the
motor can become very hot. Now, go to the status tab and use the set
target interface at the bottom of that tab to command your motor to go to
different target positions. If the set target checkbox is checked, you can move
the stepper motor by dragging the scroll bar.
Increase the values on either end of the range to have the motor take more steps
in either direction.
If you want your stepper motor to take smaller steps, go back to the input and
motor settings tab and change the step mode to a lower value.
You might also want to set the decay mode for your Tic, which dictates how
fast the current through your motor coils decays during each step and matters most
when microstepping is used. Generally, using slow decay generates less
electrical and audible noise, but it can result in missed microsteps.
Fast decay is much noisier both electrically and audibly, but it creates
more evenly sized micro steps. You can also select mix decay which
automatically decides between when to use slow or fast decay and should work
well for typical applications. See section 4.3 of the user's guide for
more details about selecting a decay mode. After you've set the motor's step
mode, current limit, and decay mode, you should set its maximum speed and maximum
acceleration. The Tic represents speeds, velocities, and speed limits in units of
pulses or microsteps per 10,000 seconds. The Tic can send up to 50,000 pulses/s,
so the maximum allowed speed setting is 500 million. However, depending
on your motor and its configuration, your motor might not be able to move that
fast. To demonstrate what might happen if your motor can't keep up, we'll switch
back to full step mode with a mixed decay. Then to find the motor's max speed,
we'll use the control center's set velocity option to play around with the
max acceleration and speed settings to find out what this motor is capable of.
To do this, first we want to make sure that the control center doesn't limit
what we can set our speed to during our test. So set the Tic's max speed to
50,000 pulses/s. It's also helpful to increase the max acceleration.
This setting dictates how quickly your motor will achieve its set speed. On the
default of 400 pulses/s², it can take quite a bit of time to
achieve higher speeds.
Add a couple zeros to the settings so you don't have to wait around forever
for the motor to get up to its set speed. Note that if you find your stepper motor
is losing steps during the speed test, this could be a sign that your
acceleration setting is too high, and you should consider lowering it. Next, on the
status tab make sure you're in set velocity mode. Enter plus and minus
5,000,000 in the boxes at the end of the scroll bar so that the scroll bar range
is set to be plus and minus 50,000 pulses/s. Then in the set target
velocity box under the scroll bar, enter a relatively small number for the target
velocity. We'll start at 1,000 pulses/s. Since our stepper motor has
200 steps/revolution, this means our motor's output shaft will rotate five
times a second. Keep stepping up the target velocity
until you reach a point where your motor stops or starts behaving erratically.
Once the motor does get stuck or stops behaving normally, it's usually best to
reset the speed to zero. Then if you want a more precise idea of where the speed
limit needs to be set, reset your motor speed back up to the last speed it was
running at and take smaller steps as you increase the speed to dial in what the
max speed should be.
It seems like 16,000 pulses/s is a good max speed for this motor in
its current configuration. Keep in mind that your motor's max speed is highly
dependent on configuration settings like step mode, decay mode, current limit, and
max acceleration. It's also dependent on external factors like input voltage and
load. If you aren't achieving the performance from your motor that you
would like, consider playing around with these variables to see what's possible
That covers the basics for using Pololu's Tic stepper motor controller.
This video provided an overview of some of the topics covered in the Tic stepper
motor controller's user's guide. If you got stuck on any step of this video,
please refer to the Tic's user's guide for troubleshooting advice. Refer to the
rest of the user's guide for more in-depth information about the Tic
including instructions for setting up one of the many control interfaces
available on the Tic. If you get stuck anywhere along the way, refer to our
support page for our general troubleshooting advice and information
on contacting our technical support team. This page also gives a general overview
of what information you should provide when contacting us so that we can
provide better support faster and get you up and running with your project.
Finally, we always like to hear what customers make with our products. Post
your project to the share your project section of our forum, or share it with us
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