UT-61E: Why does it beep in "Peak" mode? - Page 1
Forum section: electronics / testgear

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 17, 2014, 10:44:14 pm
content: I turned my UT-61E on, dial straight to volts mode, and pressed "Peak". I have a small 12 DC motor attached, and I want to find the peak output when I spin the shaft. I spin it a couple of times, then the meter starts double-beeping, about once a second... any ideas?Here's what it's doing:

author: Rerouter
author_rank: Super Contributor
timestamp: January 17, 2014, 10:53:46 pm
content: What reading is it giving while spinning, upon breaking contact on the commutation plate it could be generating a spike like any other inductive load.

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 17, 2014, 10:59:12 pm
content: Quote from: Rerouter on January 17, 2014, 10:53:46 pmHard to tell; I've updated the OP to show the video though.Thanks.

author: Rerouter
author_rank: Super Contributor
timestamp: January 17, 2014, 11:03:33 pm
content: Well we can either investigate the motor, or the meter, in this case i would say motor,grab a 220nF to 1uF capacitor, and a generic 1n4004 diode to make a crude little peak detector, measure after the diode with your meter and spin the motor to get an approx peak voltage

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 17, 2014, 11:05:17 pm
content: Quote from: Rerouter on January 17, 2014, 11:03:33 pmGood idea, thanks

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 17, 2014, 11:16:40 pm
content: Okay: I made that test circuit, and it slows the peaking right down; the bar graph is easily hitting "OL" (overload). I take it that with the negligible currents involved, no harm has been done?Thanks again.

author: dr.diesel
author_rank: Super Contributor
timestamp: January 17, 2014, 11:20:05 pm
content: Quote from: rolandpenplotter on January 17, 2014, 11:16:40 pmNope, meter is unharmed.

author: tom66
author_rank: Super Contributor
timestamp: January 17, 2014, 11:23:40 pm
content: Quite possibly an alert telling you that you have exceeded the maximum voltage rating of the meter, a little motor shouldn't cause any harm though.

author: Rerouter
author_rank: Super Contributor
timestamp: January 17, 2014, 11:28:18 pm
content: now to actually measure the voltage your aiming for, are you planning to use this motor as a generator? if so then good, work out a rough load you will be measuring and try measuring the peak with that load (resistor) in parallel

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 17, 2014, 11:35:11 pm
content: Quote from: Rerouter on January 17, 2014, 11:28:18 pmDon't worry, this meter is going nuts, beeping on "peak" range when I hold a steady 5V DC on the probes :-/ talk about weird, and it goes "OL" with that same 5V DC only on "peak" mode...

author: Rerouter
author_rank: Super Contributor
timestamp: January 17, 2014, 11:49:46 pm
content: Found your problem, when you enter peak mode the range gets changed to manual,

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 17, 2014, 11:51:35 pm
content: Quote from: Rerouter on January 17, 2014, 11:49:46 pmIt says "MANU", yes, but I don't understand...:This site is well laid out, and seems to explain a few things, but doesn't explain this crazy manual mode in peak mode:http://lygte-info.dk/review/Review%20UNI-T%20UT61E%20UK.html

author: Rerouter
author_rank: Super Contributor
timestamp: January 17, 2014, 11:59:10 pm
content: either set the range to say 100V before entering peak mode or try pressing the range button once in the peak mode

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 18, 2014, 12:04:18 am
content: Quote from: Rerouter on January 17, 2014, 11:59:10 pmAh! Now I've cracked it; you set the range manuallybeforeentering "peak" mode. What a stupid manual; it doesn't even mention this. That's what happen when you release a crappy "Chinglish" manual to cover several models - they couldn't obfuscate it more if they wanted to!Thanks for your help mate

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 18, 2014, 12:25:03 am
content: Quote from: rolandpenplotter on January 18, 2014, 12:04:18 amActually, I am pretty certain I have noticed this behavior on a variety of meters. Peak mode is typically intended to find the peaks on what appears to be a stable voltage. So you basically, feed it the voltage. Let it get roughly stabilized (then hit peak).

author: gxti
author_rank: Frequent Contributor
timestamp: January 18, 2014, 12:32:35 am
content: Fluke 87 works the same way. Precision varies with range, so you don't want it auto-ranging while you're capturing min/max/average.

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 18, 2014, 12:46:51 am
content: Quote from: gxti on January 18, 2014, 12:32:35 amVery true

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 18, 2014, 01:41:29 am
content: Also, why is this in general chat and not in the Test Equipment section.Moderator: Done!Edit: Damn son you are fast!

author: GeoffS
author_rank: Unknown
timestamp: January 18, 2014, 02:20:10 am
content: Just coincidence that the move was made so soon after your post.A couple of people had reported this thread via theReport to Moderatorbutton and I was responding to that.This is the best way to bring any thread/post to the moderators attention as it sends a message to all moderators and one of us is likely to be on line.