Servo Power from the PWM Pins an RB-100???

Based on DMP's Vortex processor / SoC this board is a full computer capable of running a standard Windows and Linux installation on the backpack of your robot.
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Servo Power from the PWM Pins an RB-100???

Post by PaulL » Sat Jul 17, 2010 11:07 pm

Post by PaulL
Sat Jul 17, 2010 11:07 pm

I would like to know what kind of amp draw would be safe on the Servo connectors without pulling too much current through the board.

Does anyone (Roboard?) know what is effectively a safe current limit for the power through the PWM connectors?

I know that the power for servos is the same as what comes over the power input pins (not regulated), but I am concerned with burning or bubbling / lifting traces on the board.

I plan on rewiring / re-routing power completely eventually (using only signal and ground pins from Roboard to the servos), but I have a bot-full of servos with 3 pin connectors on them and am wondering if I can power up without letting out the magic smoke. :)

Thanks,
Paul
I would like to know what kind of amp draw would be safe on the Servo connectors without pulling too much current through the board.

Does anyone (Roboard?) know what is effectively a safe current limit for the power through the PWM connectors?

I know that the power for servos is the same as what comes over the power input pins (not regulated), but I am concerned with burning or bubbling / lifting traces on the board.

I plan on rewiring / re-routing power completely eventually (using only signal and ground pins from Roboard to the servos), but I have a bot-full of servos with 3 pin connectors on them and am wondering if I can power up without letting out the magic smoke. :)

Thanks,
Paul
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Re: Servo Power from the PWM Pins an RB-100???

Post by roboard » Tue Jul 20, 2010 3:54 am

Post by roboard
Tue Jul 20, 2010 3:54 am

RN1AsOf091407 wrote:I would like to know what kind of amp draw would be safe on the Servo connectors without pulling too much current through the board.


Hi, Paul,

for RoBoard, 10A is still safe (in our design spec. & test). :)
RN1AsOf091407 wrote:I would like to know what kind of amp draw would be safe on the Servo connectors without pulling too much current through the board.


Hi, Paul,

for RoBoard, 10A is still safe (in our design spec. & test). :)
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Post by PaulL » Wed Jul 21, 2010 11:45 am

Post by PaulL
Wed Jul 21, 2010 11:45 am

Thanks, Roboard!

The HSR-5498SG's are 300 mA at idle (I forget if that's at 6 volts or 7.2), so 20 servos * 300mA = 6A, not counting what will happen if I move a few at full speed. I'm thinking I'll bus the power separately and run the signal pins and a ground to Roboard. I'll definitely need to do some testing to see what the current peaks at with these servos (I've seen no mention of peak current in the servo specs).

Thanks,
Paul
Thanks, Roboard!

The HSR-5498SG's are 300 mA at idle (I forget if that's at 6 volts or 7.2), so 20 servos * 300mA = 6A, not counting what will happen if I move a few at full speed. I'm thinking I'll bus the power separately and run the signal pins and a ground to Roboard. I'll definitely need to do some testing to see what the current peaks at with these servos (I've seen no mention of peak current in the servo specs).

Thanks,
Paul
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Post by matt.stevenson » Sat Jul 24, 2010 8:49 pm

Post by matt.stevenson
Sat Jul 24, 2010 8:49 pm

I wound up clipping the power lines from my pwm cables and hooking them up to a separate source.

My main reason for doing so is that I use varying power supplies and I don't want 15V going to my servos.

It's a tedious process when you've got 22 servos, but I had no problems.
I wound up clipping the power lines from my pwm cables and hooking them up to a separate source.

My main reason for doing so is that I use varying power supplies and I don't want 15V going to my servos.

It's a tedious process when you've got 22 servos, but I had no problems.
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