Powering a Fluke multimeter from a Constant Power Supply

A $500 dollar multi meter usually has an external power provision. If your unit is truly 9 volts and you are supplying 9 volts with enough current I can only guess that you are not connecting it properly. Make sure the supply is not going into current limiting.

Tom

This meter doesn't seem to have any available accessories to run from anything but it's batteries.

Current limiting is something I thought of this morning and seems like a possibility. I think that in all cases we had the power supply making all 3A available.

I'm fairly certain we are connecting it properly. Plus and minus are clearly marked on the battery pack and we lined these up to the contacts multiple times to make sure we were tapping the right ones.

Thanks for your help, thoughts and suggestions!

I just mean a DC variable power supply, such that you would use in a lab etc.

--- OK. If you've got the meter turned on while you're attaching the external supply, it may be that the meter hates it and shuts itself off.

Try turning the meter off, then connecting the supply, then turning the meter on.

Also, check the output of the supply and the leads going from the supply to the battery terminals. Ya never know...

BTW, which meter is it?

JF

They are Fluke 289's I just put in a call to Fluke as well to see if they had any thoughts. Most likely they won't have anything "official" to say about connecting a power supply in that manner heh.

What you've described should work, assuming that your polarity is right and the power supply isn't going into current limit. AFAIK, there's no "cell present" sense switch or similar.

I've got one of the relatives of that series (189? 187? forget which just now) and it is indeed a battery hog. Nice meter, otherwise. Fluke does provide an option for a C-cell battery pack for additional capacity (that works with the 289, as well), so that's another option:

Fluke also has a pretty good web forum, for an additional resource:

Thanks very much for the link to the fluke site. I'm going to check if there's a possiblity that our power supply isn't supplying the 3A I expected or something like that.

If the meter is trying to pull more than 3 A then something is seriously wrong. The 189 here only draws about 20 mA at 6 V (17 - 23, depending on what it's doing) and the 189 is reputed to be the power hog in the family.

In some dvm's, the battery must be truly floating. If your supply is grounded, and the voltmeter input low side is grounded, bad stuff may happen.

Try a floating wall-wart and see if that's any different.

John

"TheRain"

..... Phil

It might be a 9V supply, or it might be a +/- 4.5V supply. Have you verified that the cells are in series, and that the meter doesn't connect to the midpoint(s) of the series?