Why won't my meters read millivolts?

[billbyrd1945]

I have a Chinese Fluke 16B and a UNI-T UT61E. I'm trying to learn Arduino. I need to measure millivolts on my current project. Both meters will display DC volts, but neither display anything on DC millivolts. I'll appreciate any help.

[Nusa]

What does the V range display for the voltage you are trying to measure in mV?

[Terry01]

How many Mv are you trying to measure? You may be trying to measure too many so therefor need to move up to the V range. I'm sure after about 400Mv the Mv range shows "OL" and tops out.

[ArthurDent]

Here's my UT61E displaying 1.80 millivolts. One thing that might have happened is that you pressed the yellow function button and the meter is set to Hz which on DC would give you all zeros. More info is needed and a photo would help. Is it set to DC and not AC?

[billbyrd1945]

Thanks to everyone. I hope these pictures will help you to help me. The sensor has a pos and neg leg and a center output pin. The output of about 0.6v is correct. But, on millivolts on either of my meters I get OL. In the pictures attached, I merely moved the dial from DCvolts to DCmillivolts.

[Karlo_Moharic]

You just answered your own question

[2N3055]

Take a manual for your meter.

What does it say about measurement ranges?

220 mV
2.2V etc...

Meaning you cannot measure more than 220 mV in mV range.  That is 0.22V.  You cannot measure 0.6V on that range. You have to switch to next higher range. That's 2.2V.

[Nusa]

To be clear, you're simply exceeding the range of the higher resolution mV scale provided by the meters.
In the case of the UT61E, that limit is stated to be 220mV, resolution 0.01 mV, in the manual (findable online if you've lost yours). On the V setting, when the reading is under 2.2V resolution is 0.0001V (0.1 mV).

The answer is don't use the mV scale for this case. Read the V scale. Convert to mV if you want.
0.6038V = 603.8 mV

I didn't look up the numbers for your fluke, but it's presumably a range issue there as well.

[billbyrd1945]

Okay. I get it. I wondered about that from the get go but doubted anyone would build a meter that wouldn't display all values while having the technology to do so at no extra cost (presumably). I did look in the manual. It started with 你好

I don't read a word of Latin so figured I'd just have to wing it. Thanks guys. I'm good now.

[Nusa]

Here's an English version of the UT61E manual, then, for your reference. Specifications start on page 42.

https://www.batronix.com/downloads/UNI-T/UT61_Manual.pdf

[billbyrd1945]

Thank you very much. This has been a good learning experience for this 73y/o.

[Mechatrommer]

OL = Over Load.. did i just do that?  or its already there?

[Nusa]

OL = Over Load.. did i just do that?  or its already there?

It's in the manual I linked. OL = "The input value is too large for the selected range."

[billbyrd1945]

"It's in the manual I linked. OL = "The input value is too large for the selected range."
Thanks once again! I always thought OL meant open line.

[Mechatrommer]

yes that is resistance mode. whatever it is as long as it helps our mental picture.