Re: Geckodrive asking for user input

Those are nice optos (anti-parallel LEDs) but none are high speed.
The step opto must turn on or off in less than a microsecond (storage
delay plus rise/fall time). That is a tough spec for an inexpensive
isolator.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, erich10983@... wrote:
>
> Most of the PLCs I use have optoisolators that can be wired with
either polarity input. They have two LEDs wired opposite to each
other so either one can trigger the output transistor. I don't know,
however, if they can be used with the low voltage of 3.3 volts. I
rather doubt it but the option to used COMMON connected to either
supply polarity would be nice.
>
> As an aside, could people be a little more careful about sending
and editing the entire reply when responding to a posting. The latest
was 116K. Not a problem with a cable modem, but those with phone
hookups must get a little impatient.
>
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> 1) Be 100% backwards compatible with the existing drives. That
means
> supplying +5VDC to the COMMON terminal and require 5VDC
> step/direction signal levels. The G203 would keep an unplug and
> replace compatibility with our current drives.
>
> 2) Change the COMMON terminal spec from +5VDC to GND. The G203
> requires only 2mA max to operate step/direction optos instead of
> 16mA. The G203 has a max step pulse frequency of 350kHz (>10,000
RPM
> on a 1.8-degree motor) without any funny G201 step/direction timing
> restrictions.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>
> Earle Rich
> Mont Vernon, NH
>
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