Continuity Measurement with a Multimeter

[kripton2035]

this one make a continous sound with variable frequency depending on the ohms it measures :
https://www.elv.de/elv-kurzschluss-detektor-kd100-bausatz.html

[SingedFingers]

This thread actually made me try something.

I've just tested my Fluke 8024B continuity on the end of two 500m reels of 7/0.2 wire. That's 1km path between the terminals.

It's still fast and sensitive!

[Zbig]

I'd love if some multimeter vendor did advanced version of that, with 2-3 tones (say <7, <15, and <30 ohm) to say how good connection is

Keysight U1270 U1273A and U1273AX have a mode like that.

[Wytnucls]

Not quite. The beep frequency can be changed by the user. There is no frequency change according to the resistance encountered.

[xrunner]

In any case, I did order a set of Probemasters for myself yesterday. Should have done that years ago I guess. 

[Zbig]

Not quite. The beep frequency can be changed by the user. There is no frequency change according to the resistance encountered.

On 1273A, you can choose SINGLE or TONE. The chosen frequency affects the constant tone in SINGLE mode only. In TONE, the meter produces a cacophony of different pitch noises and my understanding is, the frequency is directly dependent on the measured resistance in this mode.

[Wytnucls]

Tone is only available on the 1273A and 1273AX, not on the whole series.
My understanding is that tone is just a long beep, instead of a single short beep for continuity or lack of it.
There is no evidence in the user manual that the frequency changes with resistance.
Of course, if you have personal experience with the meter, I stand to be corrected.

[Zbig]

Tone is only available on the 1273A and 1273AX, not on the whole series.

You're right. I thought the only difference between U127[1/2]A and U1273A(X) was the display but confirmed what you say with the manual and corrected my post.

My understanding is that tone is just a long beep, instead of a single short beep for continuity or lack of it.
There is no evidence in the user manual that the frequency changes with resistance.
Of course, if you have personal experience with the meter, I stand to be corrected.

No, it's just labeled in a bit misleading way. "BEEP" is actually classic latched beep. It sounds for as long as you keep the probes shorted with the added "inverse" (shifted) mode when it only ceases to beep when shorted (normally open/normally closed). The "TONE" mode produces a kind of "singing" tone varying between several discrete frequencies. I agree the manual doesn't elaborate on that at all but I own two of these meters.

[Wytnucls]

A resistance-dependent tone frequency would be easy to test with a bunch of decreasing low value resistors. Have you tried the experiment yet?

[Zbig]

A resistance-dependent tone frequency would be easy to test with a bunch of decreasing low value resistors. Have you tried the experiment yet?

Not yet, but I might. I don't expect it to be dependent on anything other than resistance, though. The only other option would be a random generator and that wouldn't make whole lot of sense

[Wytnucls]

I just don't see how they can implement that with a latched system. Perhaps the meter goes into a non-latched mode with tone.

[Zbig]

I just don't see how they can implement that with a latched system. Perhaps the meter goes into a non-latched mode with tone.

Maybe I was wrong saying it's latching. I mean I think it is but it has some scratchiness to it so perhaps it's not. Anyway, I'll try to make a short video later as I wanted to test out my camera's video functionality anyway

[rsjsouza]

Not quite. The beep frequency can be changed by the user. There is no frequency change according to the resistance encountered.

On 1273A, you can choose SINGLE or TONE. The chosen frequency affects the constant tone in SINGLE mode only. In TONE, the meter produces a cacophony of different pitch noises and my understanding is, the frequency is directly dependent on the measured resistance in this mode.

Zbig, you are correct. I just tested this. From 0 to 300\$\Omega\$ the U1273A produces a tone that decreases the frequency as the resistance increases.

To access this, go to Setup menu and select "Tone" on the Continuity selection.

Quite interesting this meter...

[Wytnucls]

Can you confirm that it is a non-latching mode, like possibly on the new U1282A.

[rsjsouza]

Wytnucls, it is non-latching. I am rendering a short clip for demonstration.

(edit) the video:
https://youtu.be/fH6rL2U2oAI

[tpowell1830]

Hi Cobalt232,

Welcome to the forum.

The reason that I use the method that you describe is to test the speed at which the buzzer sounds. When testing multiple points to a common point for continuity, I rely on hearing the buzzer to confirm continuity, without looking at the meter, but focussing my eyes on the point I am testing. Using this method, you don't want to have to wait for the buzzer to sound. If you have to wait too long for the buzzer, quite simply, it takes longer to ring out the points in question, not to mention disrupting your rhythm.

Other folks may have different ideas, but that is why I do it this way.

[joseph nicholas]

I don't get it.  Why are buzzers latched at all?  Is it for people who are preoccupied with other things when testing continuity and need to shift their attention to the sound of the buzzer?  Is this for stubborn people who refuse to use their hearing to confirm until they look at the continuity led to confirm what their ears have already told them?

[dimkasta]

For me, it's just part of a good user interface.
Both work, it is just a continuity test after all... But a solid tone is a far more non-intrusive experience. Even slightly satisfying, if you are geeky enough.

I got a couple of sets from probemaster last week, and it feels so nice testing stuff

[Wytnucls]

Thanks fort the informative video. I'm surprised that the high-end U1273A doesn't have a latched continuity mode.
Perhaps Keysight can't do a latched continuity properly, because after watching Dave's review of the little brother U1272A, I learned that the continuity test is latched, but is painfully slow.

The fast frequency change in tune with resistance value is interesting, but is there a real world use for that kind of continuity test? Just wondering...

PS: Waiting for the video of the 5th.

[Rick Law]

I personally never liked latching continuity. I used non-latching continuity testers many times to locate intermittent connection problems.. Those manifest as noisy, scratchy tone.
Solid tone, solid connection. It is additional info.

For me, it's just part of a good user interface.
Both work, it is just a continuity test after all... But a solid tone is a far more non-intrusive experience. Even slightly satisfying, if you are geeky enough.

I got a couple of sets from probemaster last week, and it feels so nice testing stuff

I am of the school that solid tone should indicate solid continuity.  Speed is a good thing, but failing to show intermittent connection by continuing with a solid tone is in a way the meter lying to me.

Now different frequency for different resistance would be a great thing.

By the time a manufacturer come up functions something that every member here is happy, the UI will need a 16 page setup menu.  So simplicity is probably best.

[helius]

I don't get it.  Why are buzzers latched at all?

As you can see in rsjsouza's U1273A video, some aren't. On a Fluke meter, the latched continuity provides a consistent and dependable signal that you have found a low-impedance connection. You can sweep over a whole connector and even if you only make contact for a few milliseconds, the beep will be consistently audible. This isn't the case for non-latched meters, which might not let through enough cycles of the tone for you to hear.
Other companies' implementations of latched continuity are usually much worse than Fluke's and correspondingly less useful (the typical complaint is that they are too slow to be used this way).
One device that does do it well is the Wavetek SF10 (but as hinted in that thread, it may actually be manufactured by Fluke anyway!)

[dimkasta]

I am of the school that solid tone should indicate solid continuity.  Speed is a good thing, but failing to show intermittent connection by continuing with a solid tone is in a way the meter lying to me.

Now different frequency for different resistance would be a great thing.

By the time a manufacturer come up functions something that every member here is happy, the UI will need a 16 page setup menu.  So simplicity is probably best.

Why would you consider this lying?
It is our job to know what tool to use.

The frequency change is a nice idea. It would be nice to see new features for a change. I bought my first DMM ~25 years ago, and it had the same functionality with the ones I use today... With today's tech we should be able to get rock solid DMMs for peanuts. Not paying hundreds of dollars/euros for features that existed in DMMs 20 years ago...

[mmagin]

I've thought about designing my own continuity tester +  milliohm meter with Toneohm-like functionality.  The ability to configure the latching is an interesting idea.  More of what I wanted though was:

• < .1 volt to avoid turning on semiconductor junctions
• use of an AC signal (ala HP 4328a) to allow insensitivity to thermal EMFs
• possibly a variable resistance-to-tone-frequency response, at least because I have no idea what I'd want in practice

[dimkasta]

How about pulsing?

[Rick Law]

I am of the school that solid tone should indicate solid continuity.  Speed is a good thing, but failing to show intermittent connection by continuing with a solid tone is in a way the meter lying to me.
...
...

Why would you consider this lying?
It is our job to know what tool to use.
...
...

Hmmm...   It is just a personal preference (bias) of connotation. so I find it hard to respond to your "why I consider this lying?"  It would be like trying to explain why I like green better than yellow.

Let me try this:  A perfect solid tone for a connection implies/connotes a perfectly good connection.  If the connection is intermittent, the tone should reflect that imperfection.  When an intermittent connection generates the same tone as a perfect connection, it hid the problem - so as I said, "in a way the meter [is] lying to me."