Stepper motors - How do they work
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Posts: 46,084
Hey All,
I was recently approached by an EE who wanted to know if I know how
steppers worked. I really didn't know much more then him. How exactly do
they work? How would I control one from my stamp? I have five small ones
that I bought thinking they were DC. I'd really like to use them.
-William
Original Message
From: rick rowland <see3peoh@i...>
To: <basicstamps@egroups.com>
Sent: Wednesday, May 24, 2000 12:58 AM
Subject: [noparse][[/noparse]basicstamps] Stepper motors
> Hello,
> Many of my science and mathematics customers want more precision on our
> mobile platforms than we get from servos. So, the answer is stepper
> motors? Anyone willing to share sources, ideas, stamp software, etc to
> run steppers. What I need are motor/gears to run a 3 inch wheel and push
> around 2-3 pounds. Most of the subject matter of past e-mail covered
> hacked parts or surplus. So, I would like to also find a "dependable"
> source to send our customers to.
> TIA
>
> Rick Rowland
> http://www.smallrobot.com
>
>
>
>
I was recently approached by an EE who wanted to know if I know how
steppers worked. I really didn't know much more then him. How exactly do
they work? How would I control one from my stamp? I have five small ones
that I bought thinking they were DC. I'd really like to use them.
-William
Original Message
From: rick rowland <see3peoh@i...>
To: <basicstamps@egroups.com>
Sent: Wednesday, May 24, 2000 12:58 AM
Subject: [noparse][[/noparse]basicstamps] Stepper motors
> Hello,
> Many of my science and mathematics customers want more precision on our
> mobile platforms than we get from servos. So, the answer is stepper
> motors? Anyone willing to share sources, ideas, stamp software, etc to
> run steppers. What I need are motor/gears to run a 3 inch wheel and push
> around 2-3 pounds. Most of the subject matter of past e-mail covered
> hacked parts or surplus. So, I would like to also find a "dependable"
> source to send our customers to.
> TIA
>
> Rick Rowland
> http://www.smallrobot.com
>
>
>
>
Comments
http://www.seattlerobotics.org/encoder/may98/steppers.html It will give you
a hookup diagram and there is even a link for the code to drive it. It is
not the way I would write the code, but it looks like it would work. I have
some more compact code at home that I can post if needed.
Here is a site that gives a great explanation of how steppers work:
http://www.cs.uiowa.edu/~jones/step/
Tim
[noparse][[/noparse]Denver, CO]
>
Original Message
> From: William Cox [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=dW6uP43Ddi_JLp3e2jrXzuhIv4odfLt4E0QShrcUNFEChUZjb8WrLfPRImcv6L3gCiLcD5NWgKGSCPl4tfwxWaEduQ]william@c...[/url
> Sent: Monday, May 29, 2000 5:49 PM
> To: basicstamps@egroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
>
>
> Hey All,
> I was recently approached by an EE who wanted to know if I know how
> steppers worked. I really didn't know much more then him. How exactly do
> they work? How would I control one from my stamp? I have five small ones
> that I bought thinking they were DC. I'd really like to use them.
> -William
>
stepper motor with
a "standard 23 frame size"
what does this mean??
Original Message
From: "Tim Goldstein" <timg@k...>
To: <basicstamps@egroups.com>
Sent: Monday, May 29, 2000 7:04 PM
Subject: RE: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> One of the easiest hook-ups I have seen is at
> http://www.seattlerobotics.org/encoder/may98/steppers.html It will give
you
> a hookup diagram and there is even a link for the code to drive it. It is
> not the way I would write the code, but it looks like it would work. I
have
> some more compact code at home that I can post if needed.
>
> Here is a site that gives a great explanation of how steppers work:
> http://www.cs.uiowa.edu/~jones/step/
>
> Tim
> [noparse][[/noparse]Denver, CO]
>
> >
Original Message
> > From: William Cox [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4jCL2YMl__uTLSbQG3f8KLoRUMxOQkJ02m5SukXtL7oqzsp7QGMIQuo4ejYfs6OcKl8R8ug9QXfCGet_ayPw0Hwu]william@c...[/url
> > Sent: Monday, May 29, 2000 5:49 PM
> > To: basicstamps@egroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> >
> >
> > Hey All,
> > I was recently approached by an EE who wanted to know if I know how
> > steppers worked. I really didn't know much more then him. How exactly do
> > they work? How would I control one from my stamp? I have five small ones
> > that I bought thinking they were DC. I'd really like to use them.
> > -William
> >
>
>
>
>
flange, not the type that mount on 2 ears) are built to standard frame sizes
so they can be interchangeable. The dimensions describe the diameter of the
shaft, the bolt circle of the mount, the diameter of the mounting shoulder,
the diameter of the motor body, etc. They do not define the length of the
motor, the electrical characteristics, steps per revolution, or the output
torque. The standards are issued by an organization called to as NEMA (I
think this stands for National Electrical Manufacturers Association) and are
usually described as NEMA 23, NEMA 34 etc.
So, a NEMA 23 (standard 23 frame size) means that the motor has a 1/4"
output shaft and the mounting hole bolt circle is about 1.75" in diameter
(this dimension id from memory, so don't do making a design based on it.).
Normally NEMA 23 motors will have an output torque between 40 - 150 in/oz. I
have seen smaller and larger output values, but they are pretty rare.
Tim
[noparse][[/noparse]Denver, CO]
Original Message
From: rad0 <rden0@h...>
To: <basicstamps@egroups.com>
Sent: Friday, June 02, 2000 4:01 PM
Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> I saw a reference to a
> stepper motor with
> a "standard 23 frame size"
>
> what does this mean??
>
>
>
Original Message
> From: "Tim Goldstein" <timg@k...>
> To: <basicstamps@egroups.com>
> Sent: Monday, May 29, 2000 7:04 PM
> Subject: RE: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
>
>
> > One of the easiest hook-ups I have seen is at
> > http://www.seattlerobotics.org/encoder/may98/steppers.html It will give
> you
> > a hookup diagram and there is even a link for the code to drive it. It
is
> > not the way I would write the code, but it looks like it would work. I
> have
> > some more compact code at home that I can post if needed.
> >
> > Here is a site that gives a great explanation of how steppers work:
> > http://www.cs.uiowa.edu/~jones/step/
> >
> > Tim
> > [noparse][[/noparse]Denver, CO]
> >
> > >
Original Message
> > > From: William Cox [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=OnNsnhhUTj6qVbEL5GtdoupUqxwsZMwhgIFhY0OuvB-xpJwCAl7mXoBZgSA8fi2Y4Bt_FwNSSbr3rDtbAhPO4Bsp_Q]william@c...[/url
> > > Sent: Monday, May 29, 2000 5:49 PM
> > > To: basicstamps@egroups.com
> > > Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> > >
> > >
> > > Hey All,
> > > I was recently approached by an EE who wanted to know if I know how
> > > steppers worked. I really didn't know much more then him. How exactly
do
> > > they work? How would I control one from my stamp? I have five small
ones
> > > that I bought thinking they were DC. I'd really like to use them.
> > > -William
> > >
> >
> >
> >
> >
>
>
>
>
>
one more I'll just ask before I get started,
a servo motor differs from just a stepper motor
because of the position feedback, right?
So, for a servo,
Where is this feedback sensor, or potentiometer, is built-in
the motor or do you have to put this outside on you own??
Original Message
From: "Tim Goldstein" <timg@k...>
To: <basicstamps@egroups.com>
Sent: Friday, June 02, 2000 7:11 PM
Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> Most of the larger size steppers (the type that have a square mounting
> flange, not the type that mount on 2 ears) are built to standard frame
sizes
> so they can be interchangeable. The dimensions describe the diameter of
the
> shaft, the bolt circle of the mount, the diameter of the mounting
shoulder,
> the diameter of the motor body, etc. They do not define the length of the
> motor, the electrical characteristics, steps per revolution, or the output
> torque. The standards are issued by an organization called to as NEMA (I
> think this stands for National Electrical Manufacturers Association) and
are
> usually described as NEMA 23, NEMA 34 etc.
>
> So, a NEMA 23 (standard 23 frame size) means that the motor has a 1/4"
> output shaft and the mounting hole bolt circle is about 1.75" in diameter
> (this dimension id from memory, so don't do making a design based on it.).
> Normally NEMA 23 motors will have an output torque between 40 - 150 in/oz.
I
> have seen smaller and larger output values, but they are pretty rare.
>
> Tim
> [noparse][[/noparse]Denver, CO]
>
>
Original Message
> From: rad0 <rden0@h...>
> To: <basicstamps@egroups.com>
> Sent: Friday, June 02, 2000 4:01 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
>
>
> > I saw a reference to a
> > stepper motor with
> > a "standard 23 frame size"
> >
> > what does this mean??
> >
> >
> >
Original Message
> > From: "Tim Goldstein" <timg@k...>
> > To: <basicstamps@egroups.com>
> > Sent: Monday, May 29, 2000 7:04 PM
> > Subject: RE: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> >
> >
> > > One of the easiest hook-ups I have seen is at
> > > http://www.seattlerobotics.org/encoder/may98/steppers.html It will
give
> > you
> > > a hookup diagram and there is even a link for the code to drive it. It
> is
> > > not the way I would write the code, but it looks like it would work. I
> > have
> > > some more compact code at home that I can post if needed.
> > >
> > > Here is a site that gives a great explanation of how steppers work:
> > > http://www.cs.uiowa.edu/~jones/step/
> > >
> > > Tim
> > > [noparse][[/noparse]Denver, CO]
> > >
> > > >
Original Message
> > > > From: William Cox [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=355ZOof_6UhKyrw-I3eiEUxipj90yd0c1hx21Y01qOhLMdPGUElzCnljQ-OZ6YPr9VpNUKzm7HqFV93kFUvoggWXYUQ]william@c...[/url
> > > > Sent: Monday, May 29, 2000 5:49 PM
> > > > To: basicstamps@egroups.com
> > > > Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> > > >
> > > >
> > > > Hey All,
> > > > I was recently approached by an EE who wanted to know if I know
how
> > > > steppers worked. I really didn't know much more then him. How
exactly
> do
> > > > they work? How would I control one from my stamp? I have five small
> ones
> > > > that I bought thinking they were DC. I'd really like to use them.
> > > > -William
> > > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
>
>
>
>
> a servo motor differs from just a stepper motor
> because of the position feedback, right?
Servo control implies position feedback, however
steppers with position encoders are common too.
Steppers offer incremental, predictable movement,
within limits - It is often desirable to run the
stepper outside these limits (Speed, for instance),
so additional means of keeping track of position
are necessary.
> So, for a servo,
> Where is this feedback sensor, or potentiometer, is built-in
> the motor or do you have to put this outside on you own??
The sensor is not necessarily on the motor - It's
purpose is to keep track of whatever the motor is
moving. This determines where it goes.
regards, Jack
position sensor built in, or not ??
Original Message
From: <goflo@p...>
To: <basicstamps@egroups.com>
Sent: Friday, June 02, 2000 9:22 PM
Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> rad0 wrote:
>
> > a servo motor differs from just a stepper motor
> > because of the position feedback, right?
>
> Servo control implies position feedback, however
> steppers with position encoders are common too.
> Steppers offer incremental, predictable movement,
> within limits - It is often desirable to run the
> stepper outside these limits (Speed, for instance),
> so additional means of keeping track of position
> are necessary.
>
> > So, for a servo,
> > Where is this feedback sensor, or potentiometer, is built-in
> > the motor or do you have to put this outside on you own??
>
> The sensor is not necessarily on the motor - It's
> purpose is to keep track of whatever the motor is
> moving. This determines where it goes.
>
> regards, Jack
>
>
>
>
uses a pot as the feedback mechanism. When you say servo motor I generally
think of a heavier duty type motor like would be used in an industrial robot
or a CNC machine. In that case they most commonly use an incremental encoder
that may be attached to the motor or is commonly attached to the actual part
that is moved so the backlash is accounted for.
Tim
[noparse][[/noparse]Denver, CO]
>
Original Message
> From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=mBYGv7Q_sBbaZpbxN94SBATZZzafkoPD0ZglUFPA5QG528Q0GHcGhkJ-Rhn_euMs3jr2XA]rden0@h...[/url
> Sent: Saturday, June 03, 2000 2:22 PM
> To: basicstamps@egroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
>
>
> So, if I buy a futaba servo motor, will it have a
> position sensor built in, or not ??
>
>
>
>
Original Message
> From: <goflo@p...>
> To: <basicstamps@egroups.com>
> Sent: Friday, June 02, 2000 9:22 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
>
>
> > rad0 wrote:
> >
> > > a servo motor differs from just a stepper motor
> > > because of the position feedback, right?
> >
> > Servo control implies position feedback, however
> > steppers with position encoders are common too.
> > Steppers offer incremental, predictable movement,
> > within limits - It is often desirable to run the
> > stepper outside these limits (Speed, for instance),
> > so additional means of keeping track of position
> > are necessary.
> >
> > > So, for a servo,
> > > Where is this feedback sensor, or potentiometer, is built-in
> > > the motor or do you have to put this outside on you own??
> >
> > The sensor is not necessarily on the motor - It's
> > purpose is to keep track of whatever the motor is
> > moving. This determines where it goes.
> >
> > regards, Jack
> >
> >
> >
> >
>
>
>
>
>
>
> So, if I buy a futaba servo motor, will it have a
> position sensor built in, or not ??
Yes. There is a very clear example of interfacing
"R/C" servos to Stamps in the BS1 documentation on
Parallax's site.
regards, Jack
> uses a pot as the feedback mechanism. When you say servo motor I generally
> think of a heavier duty type motor like would be used in an industrial
robot
> or a CNC machine. In that case they most commonly use an incremental
encoder
> that may be attached to the motor or is commonly attached to the actual
part
> that is moved so the backlash is accounted for.
To avoid confusion, when referring to a hobby servo motor these are called
PWP(Pulse Width Position)servos.
Bean, thitt@i...
-- done that too many times...
I want to 'set up' a 200 oz-in "servo" motor
to a machine.
By the way, are 'servo' motors operated/behave
just like a stepper motor, except for the feed-back??
For example, are they uni-polar and bi-polar, constructed
just like a stepper? Are there any major differences in control
from a stepper??
Thanks, I'm just getting a (my) grip on this.
Original Message
From: "Tim Goldstein" <timg@k...>
To: <basicstamps@egroups.com>
Sent: Saturday, June 03, 2000 3:54 PM
Subject: RE: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> If you mean a Futaba radio control hobby type servo the answer is yes. It
> uses a pot as the feedback mechanism. When you say servo motor I generally
> think of a heavier duty type motor like would be used in an industrial
robot
> or a CNC machine. In that case they most commonly use an incremental
encoder
> that may be attached to the motor or is commonly attached to the actual
part
> that is moved so the backlash is accounted for.
>
> Tim
> [noparse][[/noparse]Denver, CO]
>
> >
Original Message
> > From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ceMRny_BB50sX7HUbFaBwtrheqO-jjYkm5vukgLoo-5vX6SDGkzJywYHgbSgK2GDRUmiETQg]rden0@h...[/url
> > Sent: Saturday, June 03, 2000 2:22 PM
> > To: basicstamps@egroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> >
> >
> > So, if I buy a futaba servo motor, will it have a
> > position sensor built in, or not ??
> >
> >
> >
> >
Original Message
> > From: <goflo@p...>
> > To: <basicstamps@egroups.com>
> > Sent: Friday, June 02, 2000 9:22 PM
> > Subject: Re: [noparse][[/noparse]basicstamps] Stepper motors - How do they work
> >
> >
> > > rad0 wrote:
> > >
> > > > a servo motor differs from just a stepper motor
> > > > because of the position feedback, right?
> > >
> > > Servo control implies position feedback, however
> > > steppers with position encoders are common too.
> > > Steppers offer incremental, predictable movement,
> > > within limits - It is often desirable to run the
> > > stepper outside these limits (Speed, for instance),
> > > so additional means of keeping track of position
> > > are necessary.
> > >
> > > > So, for a servo,
> > > > Where is this feedback sensor, or potentiometer, is built-in
> > > > the motor or do you have to put this outside on you own??
> > >
> > > The sensor is not necessarily on the motor - It's
> > > purpose is to keep track of whatever the motor is
> > > moving. This determines where it goes.
> > >
> > > regards, Jack
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
>
>
>
>
just a plain old ordinary DC motor with positioning electronics
attached to it. Steppers on the other hand are constructed
completely different.
To control a servo you need to use PWM, and by sending different
pulses to the motor you can get it to move to different positions.
You should be able to connect them directly to the STAMP with no
extra circuitry needed besides what is already a part of the motor
Steppers generally have no electronics and either need an H-Bridge
for bipolar steppers, such as an L293D or L298 or a transistor array
like the ULN2003A for unipolar motors, though you can also force a
unipolar stepper to act as a bipolar one by using an H-Bridge.
-Chris
--- In basicstamps@egroups.com, "rad0" <rden0@h...> wrote:
> yes, this is what I'm getting at, I don't want to buy the wrong
part.
> -- done that too many times...
>
> I want to 'set up' a 200 oz-in "servo" motor
> to a machine.
>
> By the way, are 'servo' motors operated/behave
> just like a stepper motor, except for the feed-back??
>
> For example, are they uni-polar and bi-polar, constructed
> just like a stepper? Are there any major differences in control
> from a stepper??
>
> Thanks, I'm just getting a (my) grip on this.