Re: TB6600 Testing and Troubleshooting
Originally Posted by
Leander86
The left meter is in series with the "A" winding of my stepper, measuring current in the winding. The right meter is the voltage measured across the sense resistor for the aforementioned winding.
As you can see from the picture, the left meter is reading a current of .628 amps through the winding, while the right meter is reading a mere .015 volts across the sense resistor.
Doing the math, with .628 amps and .015 volts I would expect the sense resistor to be .023 ohms. It is not. The sense resistor was measured at exactly .22 ohms.
Again, through calculation, with the sense resistor being .22 ohms, and the measured current being .628 amps I would expect to see a .138 Volt drop across the sense resistor, but its not even close.
Any ideas why im seeing this discrepancy? Where is the remaining current flowing if not through the sense resistor?
I checked both the current readings, and voltage readings with 3 different meters, and the were all identical in readings.
What am I missing?
A normal DVM isn't suited for these kind of measurements, they are spec'd for DC and low frequency (50-60Hz AC only).
You could use them to measure the current on the supply input and compare the power consumption betwwen drives with the same motor, settings and supply.
You really need a scope to check what's going on.
Open source CNC electronics and accessories:
http://users.skynet.be/ldt/CNC%20electronics/THB6064AH.html