Servo pulse requirements

Lucky

So all servos have a center pulse of 1.5 ms sent every 20 ms. But if you sent a 2 ms pulse, does the time in between shorten to 19.5 ms or does it stay 20 ms.

·········· ___········ ___········ ___
·········· |·· |······· |·· |······· |·· |
·· _____|·· |_____|·· |_____|·· |_____
····· 20··1.5··· 20···1.5·· 20·· 1.5···· 20


···········____······ ____·······____
·········· |··· |····· |·····|····· |··· |
·· _____|··· |____|··· |____|··· |_____
···· 19.5·· 2·· 19.5·· 2··19.5·· 2··· 19.5

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"You do not really understand something unless you can explain it to your grandmother."


-Lucky[size=-1][/size]

Mike Green

Servos can actually tolerate a bit of variation in the time between pulses. Most of the sample code for the Stamps uses a "PAUSE 20" between pulses that may vary from 0.5ms to 2.5ms plus a few milliseconds for the execution of a couple of statements. Most servos probably would tolerate 30ms or more between pulses. You could probably adjust the "off" time between pulses if you want to be more precise, but I don't think it matters.

As far as what actually happens, that depends on what you've programmed.

W9GFO

Lucky said...
So all servos have a center pulse of 1.5 ms sent every 20 ms.

Some servos have a center pulse of 1.520 mS.

Rich H

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The Simple Servo Tester, a kit from Gadget Gangster.