Any Fluke fans out there? (Fluke 87-V DVM questions)

[Guineafowl]

Hi all,

I've bought a barely-used Fluke 87-V from eBay, and it really is a great meter. Far more than what I need as I don't use it professionally, but I hope it'll be the last meter I ever buy. I have a few questions:

1. If I short the normal test leads in temperature mode, it appears to read ambient temperature, but there is no mention of this feature in the manual. Is this a real feature or an unreliable quirk?

2. How can I find out the date of manufacture? I have the original box.

3. In LCD test mode, there are two RPM symbols, but again no mention in the manual. How do I use this feature? It would be handy for setting small engine idle speeds etc.

4. What can I use the conductance feature for? The range is 0-60 nS. Is it good enough to find insulation faults in transformers?

5. What use is the smoothing function?

Thanks

 

[Bystander]

http://en-us.fluke.com/products/digital-multimeters/fluke-87v-digital-multimeter.html
Answer your questions?

 

[Guineafowl]

http://en-us.fluke.com/products/digital-multimeters/fluke-87v-digital-multimeter.html
Answer your questions?

Sorry, I should have mentioned that I have looked on this site, and in the included manual, but other than a brief account of the conductance and smoothing features I can't find the answers I need. I'd like to know what real users use these things for.

For example, the manual and site both mention a 'built-in' thermometer, but only talk of plugging in the thermocouple. There's no indication that you can short the leads and get ambient temp.

 

[Averagesupernova]

1. If I short the normal test leads in temperature mode, it appears to read ambient temperature, but there is no mention of this feature in the manual. Is this a real feature or an unreliable quirk?

I am not that familiar with this particular meter but it sounds like what would happen when shorting the inputs to a thermocouple device. A thermocouple device develops a voltage based on the difference in temperature between the shorted end and open end of pair of thermocouple wires. To get an absolute reading, a separate temp sensor must be used at the measuring end. So, a short circuit to the thermocouple input (zero volts) would cause the meter to read whatever temperature the second temp sensor is.

 

[Guineafowl]

I am not that familiar with this particular meter but it sounds like what would happen when shorting the inputs to a thermocouple device. A thermocouple device develops a voltage based on the difference in temperature between the shorted end and open end of pair of thermocouple wires. To get an absolute reading, a separate temp sensor must be used at the measuring end. So, a short circuit to the thermocouple input (zero volts) would cause the meter to read whatever temperature the second temp sensor is.

That's interesting, and seems to be what is happening with my meter. Odd that it's not mentioned in the literature, though.

 

[Svein]

For example, the manual and site both mention a 'built-in' thermometer, but only talk of plugging in the thermocouple. There's no indication that you can short the leads and get ambient temp.

You cannot. When the meter was new, a thermocouple was included in the box. It looked somewhat like this:

 

[Guineafowl]

You cannot. When the meter was new, a thermocouple was included in the box. It looked somewhat like this:
View attachment 108288

It did come with a thermocouple, but if I short ordinary test leads together in that mode, a temp reading comes up which matches the room thermometer.

 

[Averagesupernova]

It did come with a thermocouple, but if I short ordinary test leads together in that mode, a temp reading comes up which matches the room thermometer.

Which I explained nicely. To say it cannot is quite simply wrong. A thermocouple gives a voltage based on the temp difference between the shorted and open ends of the thermocouple. It cannot give an absolute temperature reading without a separate temp sensor. So by giving the meter zero input volts this is the same as no temperature difference between the shorted and open ends of the thermocouple wire. The temp displayed will match the temp of the internal sensor in the DVM. I used to work on instruments of this type for a living.