Alt-BEAM Archive

Message #06230



To: beam@sgiblab.sgi.com
From: Wouter Brok w.j.m.brok@stud.tue.nl
Date: Wed, 29 Sep 1999 17:38:24 +0100
Subject: [alt-beam] Re: master/slave bicore


Hi,

>Now, this is my very first walker, so I'm experimenting with how to change
>it's walking. The front legs don't lift quite as high as I've seen on the
>others. Looking through some of the old messages, I found one that seemed
>to imply that using HCT's could be a problem that way. He said he went with
>AC's and got more leg movement. Anyone know what I'm talking about?

Possible. One reason I could think of is that for example your motors ask
so much current that the voltage on the outputs of the HCT drops. This will
give you motor less 'power' so to say. AC's are able to output more current
then HCT's so the voltagedrop at a certain output-current of the inverters
is less for an AC, thus more 'power' to the motors (sorry for the crappy
way of phrasing it, hope you get what I mean).

I didn't read the previous messages on the subject very well, so actually
this answer might make little sense. If you use the 240's to drive the
motor it might be the case though.

I did read though that you connected your circuit to a 6 V powersupply. I
hope you are aware of the fact that most of those logic-series chips are
said to operate from 2 to 6 volts. This is true for the HC's I use, maybe
not for your chips (have a look at the datasheets), but what jumped to mind
when I read your message was 'wow, 6 volts that's on the edge .... of
course they can take a bit more, but be carefull with it'

Well, hope you can use my comments.

Wouter Brok.



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