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Unread 18-02-2013, 15:11
EricVanWyk EricVanWyk is offline
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Re: How many servos can be powered off a single PWM terminal on the Sidecar?

Quote:
Originally Posted by Andy A. View Post
Eric- is it correct to assume that the DC power pins on the PWM ports are all supplied by the same source? In other words, is there any performance difference between using a Y cable or separate ports for each servo (possible signal issues aside)?
Your assumption is correct. All of the 6V power pins are directly tied together with nothing separating them. Power wise, a Y-cable really shouldn't have a measurable* effect.

I haven't tested signal effects, but most servos are not opto-isolated and therefore don't consume measurable signal current.


* Assuming that extra cable length is 50mOhms and 800mA draw at stall, you losing 40mV above what you would with separate power pins, which amounts to less than a 1% performance difference - and this is an extremely conservative estimate. I would imagine that it would be swamped by measurement accuracy and part-to-part variability.