Alt-BEAM Archive

Message #12404



To: beam@sgiblab.sgi.com
From: Richard Weait crs0274@inforamp.net
Date: Thu, 23 Mar 2000 19:42:37 -0500
Subject: [alt-beam] Re: A more efficient Solar PowerSmart Head


At 10:03 AM 3/24/00 +1200, Justin wrote:
>Content-type: text/plain; charset=3Diso-8859-1
>X-MIME-Autoconverted: from 8bit to quoted-printable by deliverator.sgi.com=
=20
>id OAA13692
>
>Part of a solar walker I=92m designing involves the PS Head. I was looking
>at two spare inverters on an HC240 that nothing would fit on (due to
>needing to be on when the SE-driven enable would be off), and realised I
>could use them on the PS Head. I think=85

"Oh! Danger Will Robinson! Danger!"

Your schematic showed the output of a logic gate tied to ground.
Like this:
SE--.
|
rest of circuit. . . --------|>O------.
|
|
---
0 V

This is a bad thing. The output of the inverter is connected to
ground, which is (in a manner of speaking) an output from the power
supply. When the gate is activated by the SE it will fight with
the power supply to control the voltage at that point. This will
be an additional current drain on your circuit, even if the fighting
voltages are close to identical. Think about two mountain goats,
smashing their horns together, or Dr. Doolittle's Push-me-Pull-you.

Now, to me it looks like you want to 'disconnect' the sensors when
they are not being used. Is that your plan? Or do you want the
PSH disabled?

Cheers,

Richard.

Home