Re: various types of AC/DC drives and their inputs?

Thanks Jon for your kind help!
Please tell me if any drive has pwm and direction signal as inputs
what kind of trouble we may have if we run it using STG using
some electronic circuit that can convert the +/-10 V signal
from the STG to PWM and Direction signal?
or is this aproach (converting the Voltage command signal to pwm
and dir) pefectly valid?
Asim

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>
> Asim Khan wrote:
>
> >Hi!
> >
> >I have seen a Milling Machine of MAHO, with a damaged control.
> >It has Rotary table.
> >The x, y and z axis drives are in a single yellow box. the 4th
> >drive for rotary table is separate from this box. These drives
> >are too from MAHO.
> >I am intereseted in replacing its old control with EMC and STG
> >but i am not sure about its drives (wether these are AC
> >or DC)
> >I have experience of EMC with STG and DC servo drives which
> >had +/-10 V input signal to control the direction and speed of the
> >DC motor. The motors had tacho output which was fed to the dc-drive
> >and was handeled only by the dc drive.
> >
> >I am particularly afraid of AC drives? what kind of Inputs they
> >have?
> >
> They can have any sort of input. Many have the traditional +/- 10
V
> velocity command,
> but some have other types of signals (CanBus, FieldBus, PWM,
proprietary
> signals, etc.)
>
> > Can EMC with STG can handle all kind of AC and DC drives?
> >
> If it has the 10 V velocity command, then it sure can.
>
> >I have heard that some of the AC Drives take some comutation
> >signals (what are these?).
> >
> They tell the drive what currents to run through which windings.
>
> > if yes then are these signals have to be
> >generated by STG?
> >
> Never.
>
> > or are all the required signals to run an AC
> >Drives are handeled by the AC servo drive it self?
> >
> >
> The motor should provide whatever signals the drive needs, if they
are
> from the same
> system. You just have to be sure not to cut those wires. The AC
motors
> usually don't
> have a tach, but use the encoder for this purpose. So, the encoder
may
> need to go to BOTH
> the drive and the STG card.
>
> Jon