Thread: Limiting PWM in pbasic
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Unread 24-06-2002, 00:38
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Re: Limiting PWM in pbasic
Posted by Matt Leese at 2/11/2001 1:59 PM EST


Other on team #73, Tigerbolt, from Edison Technical HS and Alstom & Fiber Technologies & RIT.


In Reply to: Limiting PWM in pbasic
Posted by Alan Federman on 2/11/2001 9:59 AM EST:



Well, you need to remember that PBasic doesn't support
floating point numbers. It only does integer math so
multiplying times .25 (if it even compiles) won't ever
do what you want. Dividing by 4 (or better yet, right
shifting two places) will work. This however just
scales down the output value. By using a MAX and MIN
you put a fixed limit and the slope of the input is the
same. When you scale down you change the slope of the
data. When scaling, be careful with being greater than
127 or less than 127 as PBasic also doesn't support
negative numbers so that will definatley give you bad
data. So for stricked limiting of values MAX and MIN
is better but if you want to slow down the robot
totally, scaling works better.

Matt


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