Hi!
Recently I bought this device (v1.1.2) and I was very happy about it until I tried to verify the current and voltage readings. Tried two multimeters and they both agree with each other. Here are the results I have:
Range 1 (~100nA - 50uA) Gain 1 is ok
Range 1 (~50uA - 500uA) Gain 0.98 at 65.12uA on the multimeter, it reports 65.77 which is also ok I guess. At 451.8uA reads 450.8uA.
Range 3 (~500uA - 5mA) is the worst! Gain 1 - at 548.9uA gives about 660.6uA, even with Gain 0.9 which is the lowest shows 594.6. At the higher end 4.36mA gives me 4.11 readings and if I adjust the Gain to 0.95 it goes close to the multimeter readings, but apparently this setup is not linear.
Range 4 (~5mA - 60mA) Gain 1 - 6.6mA gives 6.54mA - ok. 51mA reports 54.06mA
Range 5 (~60mA - 1A) Gain 0.98 - 75.29mA reads 75.7, 780mA reads 0.78 which is great!
Nothing connected and power turned off - ~20nA average, 0.38uA max??? That is on Source meter mode. On Ampere meter shows 0.00uA.
The voltage readings are also off.
U8 works fine, but U9 gives lower voltages at the output:
Voltage set | Multimeter shows
800mV 0.605mV
900mV 0.859mV
1000mV 0.970mV
1200mV 1.168mV
1500mV 1.461mV
2000mV 1.950mV
3000mV 2.946mV
3500mV 3.432mV
4000mV 3.924mV
5000mV 4.918mV
Also I found that when I close the software, the Gain values resets to default 1, so that makes their argument meaningless.
Is there anything I can do about all that? I suppose that hardware can be way more accurate, just have to have some way to calibrate it properly.
