Quote:
Originally Posted by peter_4059
Steve,
I'm not sure if it is noise I'm seeing - It looks like the cooling is causing the effect of offset to increase so the histogram is being shifted to the right. If I reduce the offset it comes back to the left. I'm not sure if there is an explanation for this - did you see the same thing?
Peter
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Yes!...I did see that. In the dark I thought I had auto-level clicked on
and that makes the histo dance around as you describe.
But it wasn't.
I'll post two extremes of histo...one at 6 deg and one at 8 deg to show
that something is different in both, and therefore makes it hard
to stack. I think normalising fixes this but it could be a downside to
the whole peltier cycle changing for a few degrees around the setpoint.
If this is what causes it then a better feedback system is needed to get
the pelitier to stay at 0.1 degree from the setpoint.
Simple relay on/off even with hysteresis just isn't going to cut it.
Even driving it with PWM and tweaking it so the temp doesn't
vary has problems. When ambient changes I have to keep tweaking.
More dabbling needed
Steve