I posted this in beginners because I think I am missing some stupid menu setting or something. I am still getting used to my 34401a multimeter as well.
I purchased a 34401a multimeter about a week ago and I put it through it's paces with a few different test setups and it seems to be working fine. It also passes all internal tests and has no errors. However, there is one weird quirk: There seems to be a hard limit of about ~0.4a on DC amp range on the multimeter.
It is rather strange.
DUT: 34401a
Setup: Charging an A123 AHR32113M1 battery with an E3632a power supply, measuring the current through the battery. Battery can handle high current fast charging.
The power supply is set at ~4.1v in CV mode and the PSU measures the charge current at 1.2amps, and it starts dropping. This is normal.
I plug in my fluke 115 in line with the charging battery and it measures about 1.2 amps. This is consistent with the power supply. I disconnect my fluke 115 and use my 34401a multimeter. The charge current reduces to ~0.4amps. I know the multimeter is limited to 3a RMA, but 0.4a is well below that. I dont know why there is such a significant difference between the current readings. There was a service note for the 34401a about replacing a few internal resistors on the multimeter to improve dc current measurement, but I don't think the issue would be this significant. This also seems to be too significant of a difference for burden voltage to be the reasoning.
Am I missing something? I checked the multimeter menu settings and it the only "limits" I found were in the math modes. High and low limit were set to 0.0000.
I checked the terminal fuse and it looks correct at 250v and 3a. The overall multimeter fuse was 250v at 325ma, as stated on the back.
I have no idea what else can be causing this.
If anyone has any input, that would be fantastic. Thanks!