DMM Vs VFD - Low Pass Filter - Fluke Fridays - Episode 97

[@rondj1965]

I just bought a Fluke 87V MAX DMM, and wanted to see what the LoPass filter function does. Great video and easy to understand. I install VFD's frequently (no pun intended), so this function will be great to have. This 87V MAX is a beast, and probably the last meter I'll ever buy. Thanks for sharing your knowledge.

[@tnt-hv6qw]

really cool. didn’t know that. luv the vids. thank you

[@toolcartel4213]

Heard of it. Thank you for your content brotha. Always good stuff, I’m deep into fluke with a growing collection. Looking into upgrading my 771 to a 773 also looking into the 789 and 726. Can you please do a comparison video of these and why you would go with one or the other. I believe I know but would love to hear it from the expert to make sure I’m on the right track. Thanks! Keep up the good work

[@billmuertos]

Awesome vid thanks. I hadn't heard of it

[@iamsevenfeet]

How to measure the frequency of the VFD? please~

[@patrickhayes-foley6390]

Heard of it as I'm looking for a new meter; vfd measurement is compulsory (my present one doesn't). VFDs are quite common now so it's an attractive feature; I can't see other manufacturers not implementing it. The Major Tech MT1009 states that it has this a low-pass filter function. It may help to briefly explain, with a diagram, how the vfd output is synthesised from a much higher frequency. Also, measuring the frequency with the LP filter on and off would be instructive.

[@electrotools8083]

nice video!

[@devkashsingh4691]

Hello Hi What about the fluke 179 multimeter the LPF function has or not

[@fridayswithbrandon]

@@devkashsingh4691 I don't believe it does.

[@harveypaltridge]

Heard of it. But interested to know if the 378 FC it is just an automatic function and switches itself between low pass and True RMS? Wonder if Brandon can answer this?

[@fridayswithbrandon]

True RMS and low pass are not mutually exclusive. All of the Fluke meters are True RMS at this point other than a couple specialty meters and a couple legacy meters. But even with a True RMS meter you can have a low pass filter on it and activated or not on it/turned off.

[@harveypaltridge]

Heard of it Brandon. How do you engage the low pass filter on a 376FC?

[@fridayswithbrandon]

It's always engaged. You can't turn it off. Because it's not designed to be used on the circuit board level.

[@douglasgimenez5480]

Great explanation, congrats. Is it possible to download this fluke manual you have?

[@fridayswithbrandon]

Here is the Fluke catalog: dam-assets.fluke.com/s3fs-public/220396-en-2023-2024-product-guide-complete.pdf?dzNiQLLBvwidZk6.KI64us0XLO0WW2KY

[@douglasgimenez5480]

@@fridayswithbrandon Nice, thanks a lot!👏🏼

[@eightequalsequalsdee]

Any situation where you wouldn't want the LPF on?

[@fridayswithbrandon]

from Tech support Jim Newell: The Low Pass Filter is just that it’s a filter to change the frequency response of the meter. As an example, the Fluke-87V Max bandwidth for measuring AC voltage with the Low Pass filter off is 15Hz to 20kHz, with it on the bandwidth is 15Hz to 440Hz. See below specifications I clipped out of the manual. Remember the Fluke-87V Max is meant to be used in more than one genre (not just electrical), it can be used in automotive or electronic as well. The reason you would not want to use the Low Pass Filter is you have applications where the limited bandwidth would prevent you from getting results. This would typically be in electronic applications. The VFD by design is trying to create a waveform using multiple changing frequencies which the Fluke-87V Max will try to measure all of the changing frequencies and it’s not able to keep up with the constant fluctuation using it’s full bandwidth, hench using the Low Pass Filter solves that issue.

[@eightequalsequalsdee]

@@fridayswithbrandon Thanks! Do you happen to know of any examples of electronic applications where the LPF would prevent getting results?

[@fridayswithbrandon]

@@eightequalsequalsdee if you looks up the user manual for 87V or 87V MAX. Under AC voltage it has a table that shows exactly what frequency it changes the accuracy on.

[@MrImperial67]

is the low pass filter the same as the loz feature on models like the 117?

[@fridayswithbrandon]

No loz is to get rid of ghost voltage. Low pass filter is all about VFD and eliminating the carrier frequency voltage.

[@billmuertos]

@@fridayswithbrandon What meters from Fluke have loz function? Does 1587C or 378fc? Or do they have a function that is comparable?

[@fridayswithbrandon]

@@billmuertos I don't think either tool has Loz. If you want a list of tools that has it I would call 800-44-FLUKE. They would be happy to help you.

[@mikeadler434]

Yup! 👍👍

[@duchche]

Never 👂 before about it

[@chaisritrikong2623]

I'm from thailand. I want to Review fluke 279FC.

[@bobbauvian7700]

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