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Using ULN2003 to drive a bipolar stepper motor

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Maverickmax

Maverickmax

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Hi

I want to be sure that it is okay to drive 12V on ULN2003 in order to drive the stepper motor while AT89C51 operates at 6V?

Please advise me asap

MM
 

uln2003 example

Yes this is OK ULN2003 is open collector driver.

Do not forget to use pullup resistors (for example 4K7 to +5V) as 8051 can not source enough current to switch ULN2003 when fully loaded.

best regards
 
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    K

    kewal

    Points: 2
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uln2003 chip

The supply voltage is not an issue, since you will be simply driving some transistors, through series base resistors. No problem there.

However, I do have some reservations about using the ULN2003 to drive a stepper motor. As i recall, it has internal diodes. If you use a stepper motror with center-tapped windings, then the diode on the half of the winding that is not driven will clamp the voltage, resulting in higher current. Therefore, DO NOT connect the COM pin anywhere, leave it floating.
 

uln2003 pin diagram

C-Man said:
Yes this is OK ULN2003 is open collector driver.

Do not forget to use pullup resistors (for example 4K7 to +5V) as 8051 can not source enough current to switch ULN2003 when fully loaded.

best regards
Click to expand...

Ok, Im currently using (M42SP-7) bipolar stepper motor which consists of 4 wires. Thus should I use four pull-up resistors on each connection (PIN 1 to 4) between 8051 and ULN2003?

Look forward to hear from you asap

MM

Added after 1 hours 5 minutes:

Hi again

I want to be sure that Im not mistaken on few things.

Basically I use AT89C51 chip to control a M42SP-7 stepper motor via ULN2003 chip. I have learnt summat from C-man stating that I need to put pull-resistor to 5V between 8051 and ULN2003.

By the way, is any way to test quickly the stepper motor to move without the use of microcontroller chip and ULN2003?

MM
 

working of uln2003

I blew my bloody ULN2003 up! Im sooo pissed off! Fortunately I had to run and bought another one from Maplin 20 mins ago.

I think the reason of my chip blew up is due to 12V connected to the A to A and B to B windings of stepper motor. I did exactly the same thing as shown below:


I use to drive ULN2003 with 12V instead of 5V. Please be aware that Im using AT89C51 chip

Any suggestion?

Im soooo pissed off!
 

uln2003 connection

Do you know the resistance of the coil per phase?
I meam, does the motor draw more than 0.5A/ phase?
Just measure the resistance of each phase and see what current it will draw at 12V.

Also, try connecting a 1~2k resistor from the COM pin to +12V, to suppress spikes.

To test the motor without the micro is possible, but it takes patience. Just disconnect the wires from the ULN2003 and connect them to ground by hand, one after another. If the motor is OK, you will see the shaft move one step at a time. When you find the proper sequence, you will see the shaft move step by step in the same direction. If you want, connect the coil to ground through an ammeter. That will give you the current in each phase, so you will know if it's safe for the ULN2003.
 

    Maverickmax

    Maverickmax

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uln2003a example

it all depends on the current drawn by the motor ..... it its high......ic will get damaged....better use transistors in darlington mode or evem mosfets like irf640,540, or tip144
 

uln2003 working

you can use L298 too.it's good choice
 

bipolar uln2003

VVV said:
Do you know the resistance of the coil per phase?
I meam, does the motor draw more than 0.5A/ phase?
Just measure the resistance of each phase and see what current it will draw at 12V.

Also, try connecting a 1~2k resistor from the COM pin to +12V, to suppress spikes.

To test the motor without the micro is possible, but it takes patience. Just disconnect the wires from the ULN2003 and connect them to ground by hand, one after another. If the motor is OK, you will see the shaft move one step at a time. When you find the proper sequence, you will see the shaft move step by step in the same direction. If you want, connect the coil to ground through an ammeter. That will give you the current in each phase, so you will know if it's safe for the ULN2003.
Click to expand...


**broken link removed**

According to a data sheet of M42SP-7, since Im using 12V, the resistance would be 50Ohms. However I have checked it with my meter as you suggested. It says 11ohms. Hence the current would be approximately 1.2Amp! (No wonder the ULN2003's flying debris went past my face!)

I will give it a try using without microcontroller chip and report here asap.

Alternatively I have tried to use 4050N Buffer with 4 1k resistors TIP3055 transistors and diodes. So far there was no explosion. However I want to express some concern regarding connecting 12V to 4 windings of bipolar stepper motor. As being caution, I make sure that I didn't leave it running too long, I have notice that all of the transistors were very hot. Then I disconnected the connection between 12V and 4 windings of stepper motor, the transistors didnt get very hot.

As attached a diagram below, it is very similar my circuit apart from transistor as I am using TIP3055 at the moment

I would appreicate your time to answer my questions

Thank you

MM


[/url]
 
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pin diagram of uln2003

Hi

How I know that I have connect the 4 wires connected to transistor and connect to 12V correctly? Cuz I think I have made mistake by connecting them in order. Not entirely sure yet

MM
 

uln2003 example circuit

Hi

Here is my stepper motor's connector and diagrams as shown below:

Do you spot any mistake in my diagram? Is there mistake especially on stepper motor's connection with 12V?

Look forward to hear from you asap

MM
 

uln2003 8051

You can try 4 darlington transistor like BDX53

In most cases, stepper motors must be current regulated, for example you can see the L297/L298 schematic where there are shunt resistors and PWM current regulation for the motor windings

I see that you have a little motor, so I think that 1.2Amper is too high
 

detail of pin diagram of uln2003 chip

Is it true that it would be simple to use unipolar instead of bipolar stepper motor
because of its complexity?

Is it feaisble to drive L298 with bipolar stepper motor via AT89C51?

MM
 

bipolar stepper motor uln2003

if that motor of insurance is bipolar, you needed another interface for the handling, like bridge of H in each coil or l293
 

pic16f irf640

The motor you have is bipolar. It only has 4 wires. I would think that is why the ULN2003 blew up.
It is easier to use unipolar motors, however, with the bipolars you get more torque.
Of course you can use the L298 with your micro.
 

uln2003

You can remove the transistors and use the L298 in your circuit without any problem and with the same software

Maybe you can implement some kind of current regulation in your sofware or using an esternal circuit
 

uln2003,connection to center tapped stepper motor

While I am waiting for L29N to be turn up at my doorstep (I have ordered two of these last night).

However I appear do have a unipolar stepper motor (12VDC,200ohm,0.9deg),

Further information can be found here:

**broken link removed**

I reckon I should give it a try with ULN2003 because it draw current about 30mA below 500mA due to a measurement on the resistance of the motor - 400 Ohm. Why do I need pull-up resistor on 4 lines between microcontroller chip and ULN2003?

MM
 

como funciona el chip uln2003

Well, your motor has only 4 wires. As you can see from the drawings in the file you provided, the unipolar motors have 5 wires.
So I would say that your motor is bipolar.

The pullups are advisable (at least on the old 8051s) because the ports only have weak pullups and the ULN2003 is nothing but a couple of transistors driven through resistors. That can take some significant current, possibly resulting in lower input voltage (the pullup is not really strong to drive the 2.7k resistor inside the ULN2003). This may or may not be the case with the AT91...
 

pic16f690 stepper motor uln2803a

In your photo I see a bipolar motor with 10 ohm windings

So now are you using a different motor?

If it is 12 volt 200 ohm (and unipolar) you can use the ULN2003
 

m42sp-7

Giuss said:
In your photo I see a bipolar motor with 10 ohm windings

So now are you using a different motor?

If it is 12 volt 200 ohm (and unipolar) you can use the ULN2003
Click to expand...

Yes that is what I intend to do it asap

Regards

MM
 

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