Kunkin KP184 mA range issue

[belzrebuth]

Hi,
I've got a Kunkin KP184 PCB version 3.0 which has a funny response in the mA range right out of the box.
The issue is that its measurement has a constant offset of 10mA.
Starting at 10mA I get no reading at all on my meter.
With the load set at 20mA I see 10mA, when load is set at 30mA I get 20mA, at 40mA I see 30mA etc.
Is this a calibration issue?
Or something else might be at fault?
Calibration procedure is pretty straightforward but requires a 25A current source which I don't have so I can't really proceed with it..
I've attached a picture of the problem.
With the load set to draw say 110mA I only see the 100..
This happens all the way down to 20mA.
At the 10mA there is no current draw from the load.

[vladant]

Hi, I guess it is not very accurate on measuring small currents, after all it is a 40A device so it has low resistance current shunt. Plus it is a very noisy piece of hardware, look at the "kp184 ripple" thread on this forum. I have just started digging in KP184 ver.4 with an oscilloscope - it is full of unpleasant surprises.

[belzrebuth]

From what I've seen in a YT video it seems that after calibrating the unit it seems pretty accurate in all ranges.
But I don't have the means to perform the calibration.
It needs a high current source (~40A) and possibly a second unit so I just gave up on it.
I'm only using it to test power supplies since my mA range is pretty much useless on my unit which is lame but it's still useful for its price and size.