Testing DVMs in the 4-20mA range

This video is in response to a viewer asking about using the Fluke 17B+ to measure a 4-20mA current loop.

[@aleksiejporiadnyj9059]

Sir, you make the best test of multimeters on youtube... Thanks.

[@JohnUsp]

10:20 - Brymen BM869s measure 3.860 mA, changed to uA, and now is 3531.0 uA. This is 8.5% less current. Why? Burn voltage? And What is the Correct measure, 3.860mA or 3.531mA?

[@joesmith-je3tq]

That's just the difference in the burden voltage. Both are correct.

[@davidprice2861]

Nifty using resistor shunt and using the V drop to calculate current. I like it.

[@fieldsofomagh]

The brymen meter looks good in action.

[@pyromen321]

Is there any reason not to wrap multiple turns through a hall-effect clamp? I find myself using 2-5 loops around my DC clamp sometimes to boost precision

[@joesmith-je3tq]

Beyond maybe not having enough length in the cable or it being too thick bend, I can't think of a reason. It's a fairly common practice.

[@wilfredprins9718]

the trick with the fluke 101 and the resistor. can that be done with any multimeter? how to calculate the size of the resistor needed? do you have maybe a video explaining this setup in more detail?

[@joesmith-je3tq]

For all practical purposes, any volt meter can measure current using a shunt. Look up ohms law. Pick the resistance and Wattage based on your meter and what you are trying to measure. kzbin.info/www/bejne/qpikZ3yflLB0htU

[@wilfredprins9718]

@@joesmith-je3tq thank you

[@Tonyplat98]

why would anyone use fluke over the Brymen if their job didn't require them to do so? I have no clue...

[@DonDenaBrenna]

it is nice to see many meters compared in use. So many people just show that a meter has a feature n move on. Thanks

[@joesmith-je3tq]

+Don Muscarella Glad you enjoyed it.

[@IGATECK]

Again thanks a lot for taking time to make this video, The shunt trick its really nice I didn't know about it, thanks God for the Ohms law do I need to use back to back diodes with 10ohm resistor to protect the meter ? and can I use a 100ohm resistor or even 1Kohm to get volts instead of millivolts ?

[@joesmith-je3tq]

+IGATECK No problem. Sorry but I can't be of much more help. I do not know the systems you are working on or anything about the environment. I would have safety concerns using a shunt the way I show in an industrial environment. I posted some of my concerns on the EEVBLOG site. The range of the resistor you could use for a shunt is going to be determined by the system you are working on.

[@IGATECK]

+joe smith ok thanks for all the help and I think I will buy the Uni-t ut210e I think its a really nice meter for the price and I can always wrap a couple coils around the clamp to get a more accurate reading, and I'll check the blog thanks

[@joesmith-je3tq]

+IGATECK That's an excellent point and now that you mention it, I should have showed that.

[@forza890]

Hi, Can you recommend an ac/dc clamp meter (mainly for automotive use), that best/ accurate for testing parasitic draw. Price is not important. I purchased the fluke 376fc but then found out that it can not measure in the milliamps. Cancelled the order. I also looked at the fluke 902fc that can also measure micro amps up to 200 micro amps. would greatly appreciate your input. Thanks

[@joesmith-je3tq]

Nothing I would recommend to a professional. Most of what I am familiar with are for lab use and are not something you would take into a garage. You may find the best accuracy obtained using precision shunts and volt meter.

[@ArcanePath360]

I've got the UNI-T and I used it to test a linear actuator which said 3A max 12v. When I measured the current while it was running it was only reading 0.6A even though I had is hooked up to a 15A 12V supply - what gives?

[@joesmith-je3tq]

I'm not there but you are. I assume you are talking about a DC supply. Do you know how to use ohms law? Did you measure the coil resistance? Did it match the datasheet for the part? Did you measure the voltage across the coil? Did you calculate the current? If this current did not match the meter, did you set the supply to CCM and verified the meter was working?

[@ArcanePath360]

@@joesmith-je3tq Thanks for replying. The actuator was bought from ebay and is a 12VDC 3 amp one. It is a sealed unit. I just measured the current while under load to see if I could get a way with a 3 amp supply, as usually you need a little overhead. I was surprised it was only drawing 600 or so MA and don't understand why it says 3A max on the side of the motor.

[@joesmith-je3tq]

@@ArcanePath360 Maybe its not drawing 600 or so mA. I can't help you if you don't answer the questions. Keep in mind that the rating is for some load/displacement. Again, I am not there have no idea what you are measuring. You would need to provide a lot more information.

[@joesmith-je3tq]

Maybe it is rated for 100 lbs and you are looking with no load.

[@ArcanePath360]

@@joesmith-je3tq Thanks for repying. That is true, I didn't think of the load in terms of weight. It is rated at 750N weight. Are you saying that the current would increase to push a heavier load? I measured with the Unit-T with the clamp around the positive wire going from the wireless control box to the actuator to answer one question. I am not able to measure the other stuff as the motor is sealed in a metal housing. I'm not sure what you mean by setting the supply to CCM? Also it's the first time using this meter so have nothing to verify it's accuracy.

[@RaviKumar-uy8ss]

Sir like now we have 220 volt light and if we put load on this like AC Heater then it reduce and remain about 190-200v. So the Amps we get for calculating the Watts to whom with electricity supply is to be multiply? I mean from starting 220v or loaded 190v? Please reply its very urgent to know for me

[@joesmith-je3tq]

Hire an electrician.

[@RaviKumar-uy8ss]

joe smith u dont know joe?

[@skoronesa1]

@@RaviKumar-uy8ss More like he don't know wtf this guy is saying and I don't think this guy knows what he's saying either! lolz

[@wiktoriaslominska8078]

I don't know what he is saying either...

[@RaviKumar-uy8ss]

@@wiktoriaslominska8078 hahahaha... mam