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ut-robotics / picr22-team-teletupsud

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DRV8243 incorrect current limiting #24

Closed ReikoR closed 2 years ago

ReikoR commented 2 years ago

image

From datasheet: image image image image

When ITRIP pin is connected to ground, then current regulation is disabled.

Current limit should be set to around 2-3A to help prevent motor from overheating. IPROPI resistor value should be calculated based on that.

ReikoR commented 2 years ago

image

Connecting ITRIP pin to 100k resistor sets ITRIP voltage to 2.64 V: image image

Using 10k IPROPI resistor sets current limit to 2.64 V / 10000 ohm * 3070 = 0.81 A, which might be too low to accelerate the motor under load.

Also connecting 100k resistor to SR pin sets the slew rate to highest value: image

This can't be read form the datasheet, but highest slew rate caused problems last year with motors not starting or rotating properly. Using slew rates of 23 or 28 V/usec worked fine.