On Sat, 09 Jul 2005 09:37:26 +0200, Phil <
phil1960us@...> wrote:
> OK, I'll start asking specific (and ignorant) questions.
> What are the important measurement parameter(s) of the spark? current,
> I'd guess. others?
> What is the optimal spark voltage range?
See the theory on the page with the eden supply.
> How do you measure? Standard shunt techniques? ...?
current is limited via a standard shunt / opamp, yes.
> Is the spark long lived enough to measure directly?
certainly.
> What is the relationship of gap to spark current?
The current is limited, no relationship. (If the gap is too big there will
not be a spark and no current.)
As i understand it once there is a plasma path any amout of current could
flow, so it is strictly limited by the supply.
> How do you tell between a short and a spark?
voltage.
> Is there a range of spark currents that allow one to adjust electrode
> gap via PID or similar algorithm?
As i understand it gap is adjusted by (gap) voltage, too high -> go
closer, too low-> short.
I guess one must sample that during spark. the eden edm pages speak about
you basically minimize the occurence of too high/too low readings. The
eden supply has only digital outputs for "spark" and "short", it appears.
I believe a analog measurement of the gap voltage (maybe with sample and
hold, maybe with a MPU). I do not understand how exactly the eden PSU
works here, with the diodes on the output it measures something in some
way. Not sure.
> What effect on the spark does the electrode shape and/or material have.
> By the way, a raster approach could be sped up by using multiple spark
> electrodes. Might have to offset them a bit though I'm not sure about
> that.
time is not a issue right now, for me. first one must work!
> Any reason why one should not use a bidirectional raster
> approach (LR, RL, LR ...)
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