I am trying to calibrate my unit. I am using a Keithley SMU set to 9.99V, in a 4-wire configuration so that the current in the leads doesn't offset the voltage measured at the load.
The unit ends up reading 10.6V at 2A load; 10.3V at 1A; and 10V at 0A. That corresponds to 0.3 ohms of uncorrected resistance between the front panel and the PCB.
Anybody got any ideas?
Thanks in advance!
At least in my unit I found that the physical size of the wire going from the front panel to the PCB was causing a decent voltage error at higher currents (can't remember actual values). I ended up replacing it with some beefy 12guage and adding some additional beef to a PCB trace segment that was a little thin in my opinion. Increased unit accuracy quite a bit.
Thanks, Eric! I should have posted that, after playing with the cal a bit, my unit is much, much closer. I was obviously not quite calibrating it right. My unit has a sense trace that carries no current.