DL24P Calibration

[SpottedDick]

Hi All,

I know we have the "cheezball load" thread, but that's gotten quite long and I want to focus on calibrating the unit anyway.

The issue I have is that I blew the MCU up and had to get replacement ICs from Atorch. The replacement ICs have obviously no factory calibration on them, so I had to do this myself.

1. Voltage.
This one seems like it should be easy. When you go into the menu, it has an option for a 30V calibration point. So I connected 30V to the voltage in pin, selected the option and presto! 30V shows perfectly. The problem? The lower end (where I will be mostly using the unit, like 4.2V 18650s) is WAY off when I do this. Yes, I did connect no load to the unit and do the 0 option as well. However, for example a 4.2V battery shows as 3.5V! What am I doing wrong here? Yes the unit is 4 way wired correctly and the voltage measured at the input pins is accurate, but the display is not.
(EDIT: I may have figured this one out, but blew my 30V voltage source, so I can't verify it just now. I'll update when I get the 30V supply working again if my theory is correct).


2. Current
This is completely alluding me. So like the voltage calibration option, it has a current calibration point of 3.0A. You'd imagine I'd just need to select this option when I have a 3A load connected and the job would be done, the problem? You can't get into the calibration menu when the load is on! Anyone know how this would be calibrated in the factory? It's only out by 50mA, but I'd still like it to be accurate.

Any replies appreciated. Thanks!