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TIC T500 coil current stabilization time after energize


#1

Hello,
I recently bought a Tic T500 step controller and decide to test it with this step motor:

I followed the instructions on the relative page on the Pololu website and tried to used the USB software on my PC. I set the motor current to 1.5A and microstep to fullstep. I’ve connected a 10A 24V power supply to the controller. By using the controller I noticed some strange things:

The first time I energize the whole thing (first switch ON power supply, then energize motor from TIC software), I hear a buzzing noise coming from the motor. This noise disappears in 15-20 seconds. If I try to command the motor during this time, it does not move (blocking noise) or it moves “randomly”. If I wait 15-20 seconds without commanding and then try to command, the motor responds good at high pulse rate (>500pulses/s). At low pulse rate (<500 pulses/s) it goes like 90% of the steps forward and 10% backward.

I’ve tried to use the controller with another stepper motor from the same company (not the same stepper but similar characteristics) and I had the same behavior. I tried to lower the current to 600mA but the behavior remains (the buzzing noise from the motor disappears).

As a last thing, I tried to command these motor with a A4988 driver with STEP-DIRECTION signals given by a microntroller and I had no issues at 1.5A even by applying the step signal after a small amount of time after ENABLE signal (less than 100ms).

Does anybody any idea on which is problem I’m experiencing? Is it the motor type? Do I have a faulty TIC Driver?

I have to say that I have checked the wiring of the motor and of the TIC and it does not seem to be related to it.

Thank you in advance.


#2

Hello.

I am sorry you are having trouble with your Tic T500. Do you have a 12V supply you could test your system with to see if the behavior changes?

-Nathan


#3

Hi Nathan,
thank you for your fast response. I have tried with 12V and it behaves much better. The noise on the motor at high current (1.5A) still remains (much lower) but the step motor behaves good directly after energizing.

Can you please explain me why 12V is better than 24V and how to choose the right supply voltage for my motors? I have read this page https://www.pololu.com/docs/0J71/4.1 but I can’t find the answer to my question.

Thank you.


#4

The problem is a result of the voltage on the board dropping too quickly from a combination of the higher supply voltage, low resistance of your motor, and low inductance of your motor. The voltage and resistance together determine what the current would want to go to (over 10A at 24V and 1.8 ohms), and the inductance affects how quickly the current would change (the stepper motor driver needs some time to react to the current to regulate it). If the supply voltage is too high for the stepper motor being used, the board cannot react in time to keep the voltage on the board from dropping too much, which causes the driver to reset (and therefore lose steps). We are working on a revision to make this particular Tic more robust to this scenario, but at the moment, we do not have some exact guideline for where the limit of voltage, resistance, and inductance is.

-Nathan


#5

I understand now the problem, thank you for the explanation. In my application I need to use a I2C stepper driver and energize and denergize after operation (to avoid electrical noise of the motor). I read that you are working on making this Tic more robust on this scenario. Do you think I can I use it with 12V with reliable operation? If it is not possible with this Tic, can you suggest me another driver (maybe another one of the TIC (Tic T825 or Tic T834)) that has I2C port and is more reliable for this kind of usage?


#6

Yes, we did some testing with a similar motor here and it seems like your motor should work reliably with the Tic T500 at a 12V supply voltage.

-Nathan


#7

Hello.

We spent some time looking into the behavior you noticed, and we have just released a new revision of the Tic T500 that works better with low-resistance, low-inductance stepper motors at high supply voltages. This revised design should eliminate the specific step-losing issue it appears you encountered. We can arrange for free replacements if you email us with your order information.

-Nathan


#8

Hi Nathan,
thank you for your response. So the new revision is working even at 24V with my motor and with my manner of using the TIC?
By the way, I bought my TIC T500 at an Italian reseller: https://www.robot-italy.com/it/3135-tic-t500-usb-multi-interface-stepper-motor-controller.html. Do you think you can do something about that too?
Thank you very much.


#9

Yes, the new revision should work under those conditions, and yes, we can get you a free replacement even though you ordered from a distributor. Please still email us your order information so that we can coordinate with Robot-Italy so that they do not separately have to send you a replacement.

-Nathan