Quote:
Originally Posted by kamocat
In other words, the motor current (as measured by the Jaguar) is useless for determining the torque output?
|
At very low torques (like no-load), probably. Look at the datasheet. The accuracy is +/-2amps for currents <8amps.
That's why you always want to validate your test method against something that is known, before using it to gather data for an unknown.
The Black Jag uses an INA193AID current-sense chip across a 0.001 ohm shunt in the high side of the bridge. The INA193's analog output is sent
directly to an ADC pin in the Jag's LM3S2616 microcontroller, without any hardware (RC) filtering.
So... it depends on what the LM3S2616 firmware is doing. Is it doing some sort of digital filtering? Is it timing the ADC samples to remain phase-locked with the bridge switching? Unless someone intimately familiar with the design is willing to comment, the best way to tell is to compare the Jag's current sense values with oscilloscope current waveform traces taken across an external precision shunt, under various test conditions.