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First of all, I'm testing load regulation using keithley 2000 meter to measure input voltage and keithley 2420 sourcemeter for load current. My load setup is from 0A to 3A, 0.5A steps and Vin is 12V. Please see code below. My problem was, when I measure input voltage at 0A load, I'm measuring 12V which is fine but when the program increments the load to 500mA, I'm was measuring 11.2V for input voltage. And then after that, the rest of the load steps, I'm measuring 12V for input voltage, which were fine. I got stuck with this problem. I appreciate any help. Thanks in advance.
def config_keithley_isrc(): # configure setup for the keithley 2420
def measure_vin(): # configure to measure the input voltage
input_voltage = keithley_vin_dmm.read_values()
def measure_iout(): # configure to measure current from the keithley 2420
- Keithley Applications
- Posts: 2847
- Joined: June 10th, 2010, 6:22 am
- Country: United States
What is the voltage compliance set to? The code you provided shows it is at 21V which should be fine.
But what is the voltage measurement range set to? I would suggest it be set to 21V range.
Maybe you are in "range" compliance.
Can you perform this sequence on the front panel and not use software to see if the 500mA still gives the 11.2V on the Model 2000?
Maybe that will give us a clue.
It was fine when I use the front panel (tested manually). Just to let you know that I'm testing a Buck Regulator circuit with the keithley 2420 connected to the output as load and I'm sinking current. So, in my program, I'm converting the current to a negative value. I think you're right, it's a software problem. Maybe there's a setup or command missing in my program. Thank you for helping me on this one. I appreciate it.
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