Re: Re: Re: emc and following error problems

>    From: Jon Elson <elson@...>

<s>

> In fact, deadband is a very dangerous thing, as it introduces a
> non-linear transfer function
> inside a control loop.  I would recommend setting deadband to 0.0 in
> all cases.
>
> I have a separate thing in the code that essentially provides a
> deadband to prevent servo hunting.
> It puts the rate generators in stop if the "voltage" is commanded to be
> less than an absolute
> value of 0.001  The simulated DACs go from 0 .. 10 V, so that is .0001
> of max velocity.

Your code writing here sounds like a good thing for your stepper and
servo setups. I can see how the traditional deadband also fed in to the
position loop would work this way.

Just to be clear, It is still a valuable thing for traditional open loop
stepper setups. I was on a project recently where the stepper driver
would not throttle back when idle because it was hunting between two
steps. Both the motors and amps got quite warm. The hint is a noticable
buzz from the stepper motor.

Ray