Re: 0 - 10 VDC to 4 - 20 mA conversion

It is a GE AF-300E$ drive and the 0-10V only shows up on the drives
greater than 30HP.... kind of a pain because 0-10V would have been
perfect! Oh well. Beggars can't be choosers. The drive price was
right. As for age.... It was produced until about 2 years ago, and
has been out for about 6 years. Modern? So,so....

Alan

--- In CAD_CAM_EDM_DRO@y..., "stevenson_engineers" <machines@n...>
wrote:

> --- In CAD_CAM_EDM_DRO@y..., flyspeck1@a... wrote:
> >
> >
> > OK, this one should be pretty simple. Does anyone have
> > a quick and dirty circuit that will convert a 0 to 10
> > VDC output on my DAC to the required 4 to 20 mA input
> > signal (input impedence of 250 ohms) on my VFD? And no,
> > I do not have control of the DAC!
> >
> > V = IR
> > 1 volt = (0.004 Amps)(250 ohms)
> > 5 volt = (0.020 Amps)(250 ohms)
> >
> > Believe it or not, this is the first time I've actually
> > run into a situation like this. I've done a fair amount
> > of digital design, but when integrating with the outside
> > world in was always with control over a DAC (etc) and
> > have been going into 2K plus impedence. This project is
> > retrofitting a new VFD to an existing CNC control. As
> > such, I don't have any ability to control the DAC.
> >
> > Thanks,
> > Alan
>
> Alan, can you check the spec on the VFD? I have not seen a modern

one

> that can't take 0 -10 volt input.
> We fit Yaskawa, Fugi, IMO and a Uk make. They all take 0 - 10 volt

in.

>
> John S.