Re: Ways to convert step/direction signals to +/-10V analog
Posted by
beer@s...
on 2000-09-28 15:46:23 UTC
On 28 Sep, CAD_CAM_EDM_DRO@egroups.com wrote:
The first scheme that comes to mind is an up-down counter connected to a
D2A convertor sets a voltage on a cap. ( Poor man's smaple and hold )
There is a suitably sized resistor in parallel with the cap to lower the
voltage in the absence of pulses ! The resulting voltage gets fed to
one input of an op-amp ( or better still, an instrumentation amp ) and
voila !
Another scheme uses all opamps, to do much the same thing.
However ...
The Gecko drives work because they also have position feedback in the
form of a quadrature encoder sent back to them. Without this feedback,
there's no way for the step/dir controller to know when things have
moved far enough. I don't think you'll get anything like good and
repeatable positioning without some sort of positioning info.
Alan
--
Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta
> I am looking for a relatively inexpensive way to convert step/directionThis can be done fairly simply with not too expensive electronics.
> signals from a PC parallel port to the +/- 10Vdc analog needed to control a
> servor motor amplifier.
The first scheme that comes to mind is an up-down counter connected to a
D2A convertor sets a voltage on a cap. ( Poor man's smaple and hold )
There is a suitably sized resistor in parallel with the cap to lower the
voltage in the absence of pulses ! The resulting voltage gets fed to
one input of an op-amp ( or better still, an instrumentation amp ) and
voila !
Another scheme uses all opamps, to do much the same thing.
However ...
The Gecko drives work because they also have position feedback in the
form of a quadrature encoder sent back to them. Without this feedback,
there's no way for the step/dir controller to know when things have
moved far enough. I don't think you'll get anything like good and
repeatable positioning without some sort of positioning info.
Alan
--
Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta