PSN-L Email List Message
Subject: Re: Simple mini horizontal
From: "Ted Rogers" tedr@..................
Date: Fri, 9 Apr 2004 19:05:26 +1000
Tanks for the complement, I know it's not really a 'simple mini horizontal'
but it was inspired by John Lahr's model as seen on his web site.
The reason I though about using the light source in the sensor assembly to
overcome tilting was to over come the use of motors etc. to remotely level
the unit. As I am using a tapered 'flag' and tilt either due to temperature
or ground movement would alter the amount of light reaching the
phototransistor. Having set a stable sensor output level and a reference
voltage equal to it, the idea was that any (very) slow change in output
level would be compared to the reference voltage and the light source
adjusted to compensate, I did suggest 1 minute integration but about 10
minutes would seem to be a better figure.
> I took a look at John's website and I think that you did a nice job. I
> like it.
> I am fooling with using a 500 second integrator for leveling bias. The
> output of the integrator is applied to the motor at the summing junction
> of the PID feedback loop. It seems to work OK but I may just bite the
> bullet and add a second motor dedicated to simply providing the position
> bias. I hate to add the extra wire, so I will test the existing system
> for a bit before I give up on it.
> Dave Youden
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