What's the best command to free-wheel?

Questions about using encoders with the Roboclaw product line
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jwatte
Posts: 45
Joined: Thu Apr 02, 2015 11:55 am
What's the best command to free-wheel?

Post by jwatte »

If I want the wheels to free-wheel (H-bridges disconnected, no shorting/braking) what's the best command to send?
I realize that the motors will work as generators when doing this, but I'm well within safety margins on voltages here. I will just be dragging the rover over ground to calibrate the diameter of each wheel to a known distance.
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Basicmicro Support
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Joined: Thu Feb 26, 2015 9:45 pm
Re: What's the best command to free-wheel?

Post by Basicmicro Support »

There is no explicit command to put the controller in freewheel mode. The only time it does this is if an overcurrent is detected or if an under voltage is detected.

So to do what you want, my suggestion would be to set the minimum main battery voltage higher than the actual battery voltage. Then back to normal when you no longer need it in freewheel mode.
jwatte
Posts: 45
Joined: Thu Apr 02, 2015 11:55 am
Re: What's the best command to free-wheel?

Post by jwatte »

That's pretty clever :-)
dpa
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Joined: Tue Aug 30, 2016 11:57 pm
Re: What's the best command to free-wheel?

Post by dpa »

I also need a free-wheel mode. Am I correct that every time when I set the minimum main battery voltage via SetMinVoltageMainBattery() function the new voltage value is being written into EEPROM memory? And EEPROM will not last for long if it will be re-written hundereds times per day...
My robot makes a lot of small movements and after each such movement it is stopped for some time to make measurements. With every stop I want a free-wheel so that accumulators would last longer without recharging. The robot is operating on a level surface in a room, so the robot won't accidently move anywhere in free-wheel mode.
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Basicmicro Support
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Re: What's the best command to free-wheel?

Post by Basicmicro Support »

No. Only to ram. EEPROM is only written when you specifically send a Save Settings command.
dpa
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Re: What's the best command to free-wheel?

Post by dpa »

Wow, that's great! :P
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Basicmicro Support
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Re: What's the best command to free-wheel?

Post by Basicmicro Support »

Just to be clear the Save Settings command is called "WriteNVM".

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