Re: Aligning servo motor encoders
Posted by
bsptrades
on 2002-08-20 00:18:31 UTC
--- In CAD_CAM_EDM_DRO@y..., "Jason Cox" <sinergy@o...> wrote:
common are these.
When installing an encoder on a servo or stepper there is the basic
mechanical alignment.Most new ones like US digitals have a nifty cam
lock gizmo other models you use various clamp/screw methods. The
basic idea is if the unit is not a complete assembly there will be 2
parts. The encoder wheel gets mounted to the shaft independent from
the case and reader module. You need to make sure the disk rotates
square on it's mount, is aligned in the gap or evenly over the scan
head ( depending on type) , and that the scan head is even relative
to the disk. Most I have seen you basically just make sure everything
is centered relative to the shaft and rotates with little or no
wobble and they work.
When installing an encoder on a system with a home or reference
point the encoder is often used to make the homing operation more
consistent. Here you normally follow the procedure for homing i.e. do
what the home routine would do but manually. Now you move what ever
piece you can to rotate the servo so that the encoder index line goes
active.
For some AC servos the encoder is also used as the position
reference for vector control. These are like any timing arrangement
where you need to find the motor indication for the zero point and
align the index of the encoder to it. Not all AC servos use the
encoder this way but the ones that do are not happy if the encoder is
installed off zero by much.
Much past that is difficult, they make centering tools and such for
most models. You would need type info to get better specifications
such as reader gap. Very old models could be quite a pain as they
have many adjustments inside intensity, gain a/b alignment etc...
Modern ones are highly integrated and quite reliable.
Brian
BSP
> Hello,an
>
> Could somebody please explain the method and impotance of aligning
> optical encoder to a servo motor?Aligning an encoder depends on what the application is but the most
>
>
> Thankyou!
>
> Jason Cox.
common are these.
When installing an encoder on a servo or stepper there is the basic
mechanical alignment.Most new ones like US digitals have a nifty cam
lock gizmo other models you use various clamp/screw methods. The
basic idea is if the unit is not a complete assembly there will be 2
parts. The encoder wheel gets mounted to the shaft independent from
the case and reader module. You need to make sure the disk rotates
square on it's mount, is aligned in the gap or evenly over the scan
head ( depending on type) , and that the scan head is even relative
to the disk. Most I have seen you basically just make sure everything
is centered relative to the shaft and rotates with little or no
wobble and they work.
When installing an encoder on a system with a home or reference
point the encoder is often used to make the homing operation more
consistent. Here you normally follow the procedure for homing i.e. do
what the home routine would do but manually. Now you move what ever
piece you can to rotate the servo so that the encoder index line goes
active.
For some AC servos the encoder is also used as the position
reference for vector control. These are like any timing arrangement
where you need to find the motor indication for the zero point and
align the index of the encoder to it. Not all AC servos use the
encoder this way but the ones that do are not happy if the encoder is
installed off zero by much.
Much past that is difficult, they make centering tools and such for
most models. You would need type info to get better specifications
such as reader gap. Very old models could be quite a pain as they
have many adjustments inside intensity, gain a/b alignment etc...
Modern ones are highly integrated and quite reliable.
Brian
BSP
Discussion Thread
Jason Cox
2002-08-19 22:44:21 UTC
Aligning servo motor encoders
bsptrades
2002-08-20 00:18:31 UTC
Re: Aligning servo motor encoders
Jon Elson
2002-08-20 17:14:03 UTC
Re: [CAD_CAM_EDM_DRO] Aligning servo motor encoders