DMM Wrong Probe Insert Alarm Mod.

[ReVl27]

Hello everyone,

I'm using a UT61E multimeter.

There's one feature that I really miss on this model is the "Wrong Probe Insert" Alarm. I mean the feature like those on some Fluke meters, the multimeter beeps if the probe and the mode selection is incorrect.

I made this mistake all the time and would like to make a mod on my UT61E, too.

I plan to made a separated circuit, maybe add another small buzzer to beeps independently.

I just wonder is there any simple circuit to achieve this feature because I can't imagine how this feature is made???

It would be great if someone could give me an idea or explain to me how it works??

Thanks a lot!!!

[Kleinstein]

It is rather difficult to add this feature later on. The difficulty is in still keeping the high voltage safety with modification at the input stage. There usually is not much space.

The normal way to sense a probe in the current contact with a split contact ring, that will make two contacts. So this extra contact is used to sent a connector in the current input and warn you if the range is set to voltage.

The other case of measuring current with the probe in the voltage terminal is usually less critical and more difficult to test, as there can be a high voltage at that terminal. So it would be more like a mechanical switch, like a pin in the center - this would be difficult to add.

[ReVl27]

Thank you Kleinstein, the split contact ring make a lot of sense.
I'll consider more about this.

[james_s]

Depending on the design, an optical sensor might work.

Personally I'd just buy a Fluke though.

[PointyOintment]

Hello everyone,

I'm using a UT61E multimeter.

There's one feature that I really miss on this model is the "Wrong Probe Insert" Alarm. I mean the feature like those on some Fluke meters, the multimeter beeps if the probe and the mode selection is incorrect.

I made this mistake all the time and would like to make a mod on my UT61E, too.

I plan to made a separated circuit, maybe add another small buzzer to beeps independently.

I just wonder is there any simple circuit to achieve this feature because I can't imagine how this feature is made???

It would be great if someone could give me an idea or explain to me how it works??

Thanks a lot!!!

If you can accept the alarm working only with shrouded-plug probes, you could use a switch to sense the presence of the shroud, which could be easier to do in a safe way.

[_Wim_]

You could glue a plate on your selector knob that blocks the current input when voltage is selected... Ugly, but should work...