L297 Stepper motor driver

[Andy1845c]

Since I haven't been able to figure out how to make my rotary encoder drive my bipolar stepper motor..... I ordered a couple L297 drivers.

I was going off this schematic **broken link removed**

I know they are driving a unipolar motor there, but shoudn't this also work with a bipolar motor?

It says on the L297 datasheet that the 297 is normally used with the 298 bridge driver. Since I am not the brightest crayon in the box, I didn't read the entire datasheet before I placed my order, and missed the part about the 298.
I am trying to get it to work with the ULN2003 like in the schematic in the link.

Is there any reason this won't work? I haven't been able to get it working.

In the link, why is the CLOCK going into the CW/CCW pin and the DIRECTION going to CLOCK? Is this correct?

Are the 3.3k resistors just pull ups?

 

[arhi]

I know they are driving a unipolar motor there, but shoudn't this also work with a bipolar motor?

Nope, You cannot drive bipolar with uln2003, you need l298 or sn754410 or lm18298, amr2916 ...

 

[arunb]

for the L297, you need the L298 bridge driver, they work perfectly well for bipolar motors, for unipolar you could consider using the SLA7062M series.

**broken link removed**

thanks
aa

 

[Andy1845c]

Thanks guys. I guess its time for another parts order.

 

[Oblong]

Toshiba makes an inexpensive mos bipolar driver. If you are just using it for experimentation and your using small steppers it may be worth a look. No sense spending money if you don’t have to.

Digikey

**broken link removed**

Datasheet

**broken link removed**

 

[Ubergeek63]

Thanks guys. I guess its time for another parts order.

Check out the Allegro parts, they have good parts at reasonable prices and blow away those stupid bipolar ST parts.

A single $5 mosfet output part with synchronous rectifier functionality and your choice of input interfaces-serial, parallel, or step and direction.

Dan

 

[Andy1845c]

This project is making me feel like an idiot. lol

After arunb and arhi assured me that I can't use a uln2003, I am staring at the circuit and it all the sudden makes sense why it won't work with a bipolar motor and will with a unipolar.... kinda like duh.....I shoulda realized that

So I jump over to digikey and order a L298 thinking if I order one now from Digikey it should come on Monday.... and then I grumble about them being like six bucks a pop.

Oh well, I guess the only way you learn is by making dumb mistakes.

 

[arhi]

6$ for 298 ??!?!?! that's a rip-off .... you could make the h bridge your self with few transistors ..

 

[Andy1845c]

yup, thats from Digikey too. It sounds like a Radio Shack price....

Digi-Key - 497-1395-5-ND (STMicroelectronics - L298N)

 

[arhi]

yup, thats from Digikey too. It sounds like a Radio Shack price....

Digi-Key - 497-1395-5-ND (STMicroelectronics - L298N)

2.5$ in this god forsaken country I like them as they are easy to mount to cooler and work nicely for 2 dc motors (forward & revers) ... they also drive single bipolar stepper easily (from uC or from 297, whatever is your choice .. I never used 297)

check other FULL-BRIDGE DRIVER's available in your local store or you can make one yourself,
**broken link removed**

I'm sure there's plenty of ppl here able to help chose proper transistors for the voltage and current you need for the stepper

 

[Oblong]

I'm surprised at the amount of people who still use that bipolar dinosaur.

ALLEGRO makes some good DMOS full bridge drivers. Heres just one.

Digi-Key - 620-1063-ND (Allegro Microsystems Inc - A3949SLP-T)

 

[Ubergeek63]

I'm surprised at the amount of people who still use that bipolar dinosaur.

ALLEGRO makes some good DMOS full bridge drivers. Heres just one.

Digi-Key - 620-1063-ND (Allegro Microsystems Inc - A3949SLP-T)

I thought I just said that!

The fact of the matter is that hobbyists jump on the first schematic they find that does what they want and worhip it as if it were holy scripture.

 

[Andy1845c]

The fact of the matter is that hobbyists jump on the first schematic they find that does what they want and worhip it as if it were holy scripture.

lol, at least give me some credit for looking and finding a solution on my own, and not posting something along the lines of "Plz give me circuit for stepper motor driver, need very ugently - email it to me so I don't have to check back here" lol

I'll readily admit to not knowing everything (anything?). Its all a learning experiance.

 

[Oblong]

Sorry Ubergeek63 just skimmed through.

The allegro part I posted is just single channel.

But I did find an inexpensive one from Panasonic I'm going to try it out my next order.

Under $3.00.

Digi-Key - AN44065A-VFCT-ND (Panasonic - SSG - AN44065A-VF)

Data sheet

**broken link removed**

 

[Ubergeek63]

lol, at least give me some credit for looking and finding a solution on my own, and not posting something along the lines of "Plz give me circuit for stepper motor driver, need very ugently - email it to me so I don't have to check back here" lol

I'll readily admit to not knowing everything (anything?). Its all a learning experiance.

Hey, credit given joyously!

I just have seen and answered the question numerous times and each time the parts initially suggested are L297 class darlington output parts that require 4V over what the stepper wants to see requiring involved heat sinking and a lot more power than you want to drive the motor with.

https://www.electro-tech-online.com/custompdfs/2009/02/3982.pdf

$3.74 from digikey in singles if you can handle SMT. 2A max output, syncronous rectification, step and direction control. Since it is 0.4 ohms Rds instead of 1.5V Vsat, the chip dissipates quite a bit less.

Dan

 

[Andy1845c]

$3.74 from digikey in singles if you can handle SMT. 2A max output, syncronous rectification, step and direction control. Since it is 0.4 ohms Rds instead of 1.5V Vsat, the chip dissipates quite a bit less.

Dan

Yeah, wish I would have know to just order that IC in the first place. Oh well, next time i'll give it a try. Looks like it would save considerable $$$ and board space.

I've yet to give SMT a try. I have actually never etched a board before. I was going to try and make one for this project after I build and test it on protoboard.

 

[Ubergeek63]

I've yet to give SMT a try. I have actually never etched a board before. I was going to try and make one for this project after I build and test it on protoboard.

The 0.050" spacing is not real hard to work with.

0.5mm (TSSOP) is, on the other hand, quite hard to work with. I have had to mod board at that pitch, lifting to pins and soldering wires to them to correct PCB errors on prototype boards.

Dan

 

[Andy1845c]

Well, my L298 came today.

I have spent 3 hours trying to get it to work on protoboard. No luck.

Is there anyone here real familiar with the 297/298?

I don't think I have killed it with reverse polarity or anything.

I have the the circuit wired like Fig. 2 on page 8 of the 297 datasheet.
**broken link removed**

Except I don't have the OSC, SENSE or INH pins used.

I have ENABLE and VREF pulled high and CONTROL pulled low.

CLOCK is hooked to a 555 timer running very slow. I have an LED on it so I know that part is working.

I really don't know what else to say or try. I have pulled all the wires out and redone it several times figuring I wired somthing wrong. Its just not working.

Its really kind of a mess to try on protoboard. Lots of wires. The L298 in that "multiwatt" package dosn't fit in protoboard very well and its alot harder to tell the pins apart then the DIP package ICs......


AAAARRRRGGGGGGGGGGG.............................. I doubt anyone can help me since I don't even know what to write, but I need to vent!!!!!

EDIT: Damn, my 1000th post is about my defeat! Talk about insult to injury. lol

 

[arhi]

I have not used the 297 298 combo for stepper for some time now but from what I remember

I did:
- connect them as figure2
- not used RS1, RS2 (tied 1,15 of 298 and 13,15 of 297 to gnd - but you should use RS1,RS2 0.5R)
- sync left floating (not connected to anything)
- control - this one is important but I don't remember if it should be high or low, but you have to connect it high or low, check both options you cannot kill anything
- enable to high
- reset to high
- half/full - whatever you like but you have to tie it high/low, do not let it float
- cw/ccw - same as half/full - tie to high or low, do not let float
- get 555 to supply the clock

so the only thing I do not remember is control, I know I tried both options (high and low)

one more thing, the first time I connected it - the power was going trough but the stepper was not moving ... I then reversed 3/4 (initialy the 1,2 and 3,4 from the stepper were connected to 298's 2,3 and 13,14, as it was not working i reconnected them to 2,3 and 14,13)

I hope it is clear

 

[Andy1845c]

Thanks arhi.

I will work on it some more tonight after work.

If I dig out my scope and put it on one of the output pins on the L297, I should be able to see it going high and low, correct? It would be nice if I can trouble shoot this one stage at a time.