EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: gabriele on June 26, 2022, 11:01:45 pm
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Hello,
I recently brought an BM 235 multimeter, but I am not sure about its behavior, i have uploaded a video where i measure a low frequency signal in DC mode but it seems it does not refresh 5 times at seconds as written in specs.
https://youtu.be/MicxVZZ4w0k
It behaves similarly to this in terms of refresh rate: https://youtu.be/9s9LXOBknck?t=125
It's ok or i should RMA it?
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What you show is just an auto-ranging delay I think.
Press the range button to select a suitable fixed range, and see if it then performs as you expect.
Hold the range button for a couple of seconds to re-enable auto ranging when finished.
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Unfortunately the problem persists even if manual range mode is selected.
The DMM is currently measuring a 5Vpp 100mHz sine wave
https://youtube.com/shorts/r2rpKycN1LI?feature=share
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Mine behaves identically, even the 1 second complete freeze every few seconds. Feels like about 3 updates per second.
I did a quick zip through my LCD-based handheld DMM collection and didn't find anything that was much faster, although I didn't see any that had the complete freeze issue like the BM235. Of course units with bar graphs were very fast.
For raw speed on a budget I'm a fan of the older VFD bench DMMs, perhaps look for a Fluke 8840A.
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Some time it is pretty annoying that the refresh rate is not constant.
It would be nice to know if all the BM235 have the same defect or just a few
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Just tried it on a Gossen Metrahit Pro and the display update speed is not that much better than yours (auto or manual ranging didn't seem to make much of a difference).
The EEVBlog 121GW seems a bit better, but not by a lot.
Next comes the Agilent/Keysight U1241B, which I think is decent in update speed.
And the best I've seen so far is the Agilent/Keysight U1252B (and, guessing, also its OLED sibling, the U1252B), which generally has a very fast display update speed.
HTH