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

--- 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.