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24th Jun 2014, 4:04 pm | #1 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,932
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Beware Digital Test Meters With Low Battery
Re Fluke 75 MK111 which I was using this afternoon with the battery warning on and thoght all was OK. However while resistance readings were fine, the AC coming out of my Variac was reading 50/60 Volts low or more.
Thought very odd as on max it was only 180 Volts whereas normally it is up to 260 Volts ,checked with spare meter and it was all caused by the PP3 battery being down. One to watch for as not wanting to wind the Ultra 309 that is in for repair up to 260 Volts when the mains tap is set much lower.
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24th Jun 2014, 4:26 pm | #2 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
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Re: Beware Digital Test Meters With Low Battery
Very useful.
My Fluke was doing odd things recently too, and that was down to the battery as well. The trouble is, they're such damn good meters and the batteries need replacing so infrequently, that you get to trust them implicitly. N. |
24th Jun 2014, 6:22 pm | #3 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,079
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Re: Beware Digital Test Meters With Low Battery
Useful info, and surprising too - I would have hoped that if the battery was so low as to screw the calibration, that the display would have gone ---- or whatever (1o 8att is do-able with a 7-seg display).
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24th Jun 2014, 7:05 pm | #4 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
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Re: Beware Digital Test Meters With Low Battery
No,the display was fine and think it is only the second battery since new many years ago.
It read around 5Volts and just showed the battery symbol in top right corner.
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24th Jun 2014, 8:41 pm | #5 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
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Re: Beware Digital Test Meters With Low Battery
Another problem is that the low battery icon is ambiguous. To me, it does not emphasise the "low" bit enough. A picture of a battery with a line or cross through it would be clearer, or better still, the words "low battery"!
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24th Jun 2014, 9:42 pm | #6 |
Octode
Join Date: Jul 2004
Location: Dundee, UK.
Posts: 1,813
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Re: Beware Digital Test Meters With Low Battery
From the 1980s when LCDs were still quite new, perhaps no longer acceptable due to political correctness, but clear enough when you realise what it represents. I wonder how it was described on the design specification.
Maybe they considered adding a Replacement Imminent Procedure. PMM |
24th Jun 2014, 10:02 pm | #7 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,567
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Re: Beware Digital Test Meters With Low Battery
I get some very strange readings when the battery is low on my digital meter. I also have a power meter that reads volts or watts. I left it switched on for days a few weeks ago. It read the mains OK but showed a TV as only drawing 2 watts when everything was working OK! I then noticed the battery symbol flashing for the first time, changed the PP3 and everything was back to normal.
Seems that with most of these meters, not all ranges are affected the same way.
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24th Jun 2014, 10:23 pm | #8 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
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Re: Beware Digital Test Meters With Low Battery
I get caught out with my Beckmann meter. The only low battery warning is the decimal point that flashes rather than being steady. By the time that happens, it's well out of cal.
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24th Jun 2014, 11:34 pm | #9 | |
Dekatron
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Location: Leominster, Herefordshire, UK.
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Re: Beware Digital Test Meters With Low Battery
Quote:
Just went out to the shed to check its model number and noticed I left it on last time I used it. One very dead (not even coffin symbol generating) battery removed. Luckily no leakage.
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24th Jun 2014, 11:43 pm | #10 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
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Re: Beware Digital Test Meters With Low Battery
Thanks for the explanation, Chris. It went straight over my head.
Nick. |
25th Jun 2014, 10:49 am | #11 |
Octode
Join Date: Jul 2004
Location: Dundee, UK.
Posts: 1,813
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Re: Beware Digital Test Meters With Low Battery
I'm surprised Nick - you're usually one of the first to see these things. I had you in mind when I wrote that. It was late at night though.
PMM. |
25th Jun 2014, 11:06 am | #12 |
Dekatron
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Location: W.Butterwick, near Doncaster UK.
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Re: Beware Digital Test Meters With Low Battery
One answer, back to the AVO8 at least it only needs a battery for resistance ranges.
Having said that iI do love my Fluke as well and have a very early one here also that is still going strong.
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25th Jun 2014, 11:33 am | #13 |
Octode
Join Date: May 2010
Location: Worcestershire, UK.
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Re: Beware Digital Test Meters With Low Battery
My mid 90's Avo DMM flashes the whole display when the battery is likely to cause inaccurate readings, I think it also bleeps.
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10th Oct 2014, 2:22 pm | #14 |
Heptode
Join Date: Jul 2010
Location: Wellington, New Zealand.
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Re: Beware Digital Test Meters With Low Battery
Had the interesting experience of 3 DMM going wierd on me recently. Started with an old Fluke reading half the resistance on ohms, then 128 for mains voltage?? so changed battery but still wonky. Picked up an el cheapo and that too was peculiar - way off on ohms and mains voltage. Finally a third meter medium quality also played up. By then I went back to my old Hioki analogue out of desperation - then the next DMM I picked up was fine?? I don't believe in evil spirits but you'ld wonder sometimes!!
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