L297 driving a stepper help!

Other Hardware Motors, Mechanics, Power and CNC
1

I just started with Arduino and micro controllers altogether so I don't really know what im doing.
I just got a 5v bipolar stepper motor (21-02485) and also a L297 driver off ebay to use with my arduino uno

after searching around the web, after i got my motor, i found this picture of the motor i have connected straight to the arduino. is this even possible to do with out risking breaking my arduino? this would make everything much simpler :smiley:

after buying the L297 driver ic I ran ran across a lot of people who used it along with other driver ICs like L298. why is this? do I need that also?
http://ryanschenk.com/2010/03/driving-a-040-stepper-with-arduino/

my main question really is how do you set this IC up to control a stepper motor or can you?
it looks like the main inputs are:
CLOCKStep clock. An active low pulse on this input advances the motor
one increment. The step occurs on the rising edge of this signal.

CW/CCWClockwise/counterclockwise direction control input.
Physical direction of motor rotation also depends on connection
of windings.
Synchronized internally therefore direction can be changed at any
time.

SENS1
Input for load current sense voltage from power stages of phases
A and B.
SENS2
Input for load current sense voltage from power stages of phases
C and D.
this might help?
http://ryanschenk.com/2010/03/driving-a-040-stepper-with-arduino/
should i just buy a L293D IC?

Also thanks so much for any help

2

so I don't really know what im doing.

For a start read:-
http://www.thebox.myzen.co.uk/Workshop/Motors_4.html

i found this picture of the motor i have connected straight to the arduino

You can find pictures of most things, in this case it is just a picture doing that would damage your arduino. The maximum current output from a pin is just over 30mA and even if the motor took so little current the lack of diodes would zap your arduino.

I ran ran across a lot of people who used it along with other driver ICs like L298. why is this? do I need that also?

One chip does the driving, that is the actual switching of the current. The other chip does the controlling like working out how to switch the coils so that your software just has to have one pin for direction and the other to tell it to step. Without the extra chip your software could keep track of what coils to switch next. Also another function of these extra chips is to rapidly turn on and off the coils to make sure the current is kept down to the right level. The other way of keeping the current down is to just use the appropriate voltage. This driver board does all that for you. Pololu - A4983 Stepper Motor Driver Carrier

3

hello I am new to arduino,

I currently have the arduino uno with a l297 and l298 IC and applied motions stepper motor (HT23-597) i have it in series bi-polar ........

I have seen several schematics on the internet and on datasheets and no matter what i do I cannot get the motors to run reliably or with run with much torque.

I am following the diagram on page 8 of the l298 datasheet
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00000240.pdf

i have on L297 :
CW/CCW, RESET, ENABLE to 5v
FULL, CONTROL to GND
Vref to a voltage divider giving me 2V
CLOCK to a digital pin on the arduino uno
L298:
Rs1 and Rs2 i have 2W 1ohm resistors
Vs i can vary between 5v to 12v (separate power supply)

How do I send a good clock signal???
I have tried simply doing a digitalwrite HIGH and LOW with a delay after each command and the motor spins fine by tweaking the delay times and voltage applied but it ends up with almost no torque.

I read something about ramping up and down the speed???

I cant figure out what I am doing wrong

Could someone please help thank you

4

How much voltage/current are you providing the motor?

The torque a stepper motor produces depends greatly on those two things. Stepper motors are often run above their rated voltage as well. The speed you try to run the motor will also make a difference. This is inherent in stepper motors; you can only move so fast before the motor starts skipping steps.

When you say it does not run reliably, what do you mean?

5

I am have tried applying 5v and 12v neither gives me a reliable reading.

My motors actually skip steps and sometimes never move. I was able to move the motor a few times but would not work usually.

A smaller motor i happen to have works ok but when i put the applied motions motor it does not work.

I am almsot at the point at saying that the motors have some weird special internals that are only made to work with the applied motions driver and not a third party driver.

I have tried a delayMicroseconds(); and ramping the nubmber but i still have same results

I am really lost this is supposed to be a simple circuit any ideas?

thank you

6

I am almsot at the point at saying that the motors have some weird special internals that are only made to work with the applied motions driver and not a third party driver

No that is not going to happen.

Slow things down so it works reliably, if this does not happen when you do:-
Your problem could be one of two things:-

  1. you don't have enough current capacity in your power supply or driver
  2. you have wired it up wrong - that is misidentified the coil connections
7

My first guess would be that you have insufficient current for the driver, but without knowing more it's kind of hard to tell.

8

Thank you all for the help!!!! it was much appreciated and much needed.

Update on my project: I was able to wire two L298 chips in parallel in order to increase current and I also used a better power supply.

I have not tested out my circuit fully yet but I think I have enough torque for my application. I will update as soon as I conduct more tests.

THANK YOU ALL