An humble request to multimeter manufacturers - modify APO - Page 1
Forum section: electronics / testgear

author: ciccio
author_rank: Frequent Contributor
timestamp: February 07, 2019, 09:49:54 am
content: After a frustrating week of troubleshooting a prototype, I have an humble request for multimeter designers.I have many multimeters, and I like most of them: the new ones are cheap, small size and most of the time they work as promised, but there is that APO (automatic power off) function that drives me crazy.I had 4 or 5 meter connected all the time, and they wanted to save batteries, so they beeped every 5 to 15 minutes, to advise me they wanted to switch off, and I had to stop my workLet see the AN8009 (which is one of the simpler) : you can disable APO at switch on, but if you forget, it will beep, and you have to switch it off an on again. If it was set-up to check continuity, you must turn the switch to off, then to the fourth step (ohm etc), then push the yellow button for selecting beep.When you are in an hurry, this is frustrating (and other meters are more frustrating than this).I thought that a better procedure could be:- the meter beeps (and displays a flashing APO alert to show which one meter is beeping)- I touch a button (any button..)- the APO is disabled until I swuth the meter off.Any comment to this rant?Bet regards

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: February 07, 2019, 10:26:45 am
content: Is this not why you get bench meters? so you never have to worry about power or battery etc?But that aside, your suggestion seems sensible, however I would advise some kind of time-out on the second step turning off APO. If you actually want to change some setting on the meter but want to keep on APO it would be annoying if any action changes that.

author: ciccio
author_rank: Frequent Contributor
timestamp: February 07, 2019, 12:23:53 pm
content: Thank you for your suggestion.My bench has no room for more than 1 bench meter, and I never felt the need for it, but I'll begin searching for one (cheap...).It was a rare occasion, but I had to use 4 meters connected to the DUT and one more for troubleshooting..I admit, last month I bought one of the cheapest non autoranging, 3.5 digits meter that I found on Banggood, the ANENG M1, at 4.73 Euros.The rotary switch need pliers to rotate, but it's good for general troubleshooting. I could not use it in this case because I put it's 9V battery in my UNI-T 61E.Best regards

author: Mortymore
author_rank: Frequent Contributor
timestamp: February 07, 2019, 03:45:31 pm
content: The worst I deal with is the Amprobe AM-530-EUR that I have at work which APO can't be turned off.I set it to record something like temperature or so, and after 15 minutes is sleeping.

author: james_s
author_rank: Super Contributor
timestamp: February 07, 2019, 05:02:02 pm
content: This drives me nuts too, I use rechargeable batteries in my meter so it's no big deal if the battery gets drained. It's far more irritating to have it switch off while I'm using it. If they're going to insist on having APO it should be after a sensible delay like 2 hours.

author: David Hess
author_rank: Super Contributor
timestamp: February 07, 2019, 06:51:28 pm
content: This has gotten worse with more modern meters which use larger batteries yet operate for fewer hours making automatic power off more important.

author: tautech
author_rank: Super Contributor
timestamp: February 07, 2019, 07:20:43 pm
content: Quote from: ciccio on February 07, 2019, 12:23:53 pmYeah well, for the price of 4goodDMM's you can have at least a 6.5 digit bench meterwitha 16ch multiplexing card and do the same work as 16 DMM's.With a little trouble to color code the leads and build a chart to show which corresponds to the ch # you then only look at a single display or log them all to a PC display.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: February 07, 2019, 07:41:45 pm
content: Stop complaining.Pretty much all battery powered devices will try to save batteries, that is a natural thing, get some bench multimeters and find a place for them.If you cannot afford bench multimeters or space, stop complaining about APO.There is a reason for thatDavid

author: danco
author_rank: Newbie
timestamp: February 07, 2019, 07:57:43 pm
content: I think ciccio is right, for the money we spend we should at least be able to cancel the APO function if not change it's parrametters (i.e. time delay).Sent from my MI 5s Plus using Tapatalk

author: Paul Moir
author_rank: Frequent Contributor
timestamp: February 07, 2019, 08:44:38 pm
content: Quote from: ciccio on February 07, 2019, 09:49:54 amMy Mastercraft / Colluck meters do almost that. It gives a quick beep series as if to say, "Excuse me, but you left me on. I don't think you're using me so I'm going to switch off soon". Then a minute or two later signs off with a long beep, "Ok, I guess your gone then. Or if you haven't, I'm just letting you know I'm shutting down." They're such polite multimeters I often go to them first. However, touching any button just resets the APO.Unfortunately I can't find someone selling them anymore. The OEM number was HH0308C, and Canadian Tire's was 052-0052-2, which they morphed into a boring Mastech.

author: james_s
author_rank: Super Contributor
timestamp: February 07, 2019, 08:46:30 pm
content: I have bench meters, oddly enough they live on my bench though and that's often not where I am.I have every right to complain about bone-headed design decisions that everyone seems to make.

author: ciccio
author_rank: Frequent Contributor
timestamp: February 07, 2019, 08:56:40 pm
content: Quote from: DavidDLC on February 07, 2019, 07:41:45 pmSorry but I do not understand. Why should I stop complainig?From 1985 to 1990 I used a Beckman model 3020 meter that had NO APO but had about 1000 hours of battery life.My colleagues left them on for weeks.If you know a currently available meter with similar performance please let me know.Best regards

author: tooki
author_rank: Super Contributor
timestamp: February 07, 2019, 09:23:41 pm
content: Many meter models let you disable APO. On the Fluke 87V, for example, by holding the yellow button while powering it on. (I believe APO is also disabled if you have min/max mode on.) On the Keysight meters, like my U1252B, it's an option in the settings. I keep that one set to never APO, since it uses a rechargeable NiMH battery anyway.As for me, I love my bench meters, since I do nearly all my work at the bench. So not only are they out of the way and permanently in place, but I really, really like the speed of a modern bench meter. (My Keithley 2015 is the first meter I go to for almost any measurement.)

author: Fungus
author_rank: Super Contributor
timestamp: February 08, 2019, 12:33:32 am
content: Quote from: ciccio on February 07, 2019, 12:23:53 pmThat's all the space you need! Bench meters multiply in an upwards direction.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: February 08, 2019, 12:39:18 am
content: While I concede that bench meters have their merits and applications, I nevertheless have found myself annoyed by that function on more that one occasion.You are out of reach, poking at connectors and watching the meter, then a flash of the bargraph and *BEEP*You have set up more than one meter, which makes it just more likely to happen *BEEP*You have successfully probed the almost invisible test point and your other (third, fourth) hand manages to activate the stimulus and *BEEP*And another *BEEP* just as it is sitting behind a screen and you have to power down, discharge, test safe before you can touch it.There simply should be the possibility to modify the behaviour without turning it off.

author: vk6zgo
author_rank: Super Contributor
timestamp: February 08, 2019, 10:22:50 am
content: Quote from: ciccio on February 07, 2019, 08:56:40 pmYeah, I used Beckman DMMs a couple of years earlier, & they seemed to go on forever.My Fluke 77 does have APO, but it seems to detect that the instrument is being used, so doesn't interrupt my work.I had occasion to use some earlier model UNI-T DMMs at one job, & the APO didn't seem to be able to detect that the instrument was being used.I would set the thing up in some awkward spot, then just as I went to read the thing, it would power down.Of course, one reason why modern DMMs are hungry is the big, fancy, power hungry display.

author: Fungus
author_rank: Super Contributor
timestamp: February 08, 2019, 11:38:20 am
content: Quote from: vk6zgo on February 08, 2019, 10:22:50 amMy Fluke 27 still has the same battery that came with it on eBay, like, three years ago.No auto power off and it's been left on overnight a couple of times by mistake.Manual claims 1000 hours (but that might have been with a 1990s battery, when these were designed).

author: indman
author_rank: Super Contributor
timestamp: February 08, 2019, 12:08:50 pm
content: Quote from: ciccio on February 07, 2019, 09:49:54 amHi!In the Chinese multimeters using the DTM0660 processor or its analog, settings of the APO parameters are stored in a chip of memory 24C02(08).In FB cell - Automatic shutdown time (minutes) is a variable which allows to determine time of switch off of the device from 0 to 255 minutes.

author: ciccio
author_rank: Frequent Contributor
timestamp: February 08, 2019, 02:59:42 pm
content: Thank for the information.I must admit that I have not the time, the knowledge and the tools to modify the meter's firmware, but this is good to know..Best regards

author: Paul Moir
author_rank: Frequent Contributor
timestamp: February 08, 2019, 08:49:47 pm
content: Oh yes, the meter I mentioned is a DTM0660 so any of those can do what my one does. To quote the datasheet "The beeper will beep five times one minute prior to power down. Before power down, there will be a long beep. If auto power off is disabled, every (preset power off interval) the beeper will beep five times." Also the Select button can be used to wake up the meter so you don't have to change settings.If you ever get into it, reprogramming is easy. I used a TL866. My meter "peeve" is the ohm-continuity-diode cycle button: I reassigned those functions to selector root positions.

author: _Wim_
author_rank: Super Contributor
timestamp: February 08, 2019, 09:27:38 pm
content: With my Brymen (bm869s), when you press the select button while turning on the meter, APO is disable unit next power on. So this way you can use the meter with and without APO depending on your preference.

author: james_s
author_rank: Super Contributor
timestamp: February 08, 2019, 09:50:04 pm
content: I wish there was a way to permanently disable it, or set it to disabled in a way that persists until I choose to enable it. It's a bit like those obnoxious start-stop systems so many modern cars use to exploit a loophole in the way emissions are measured. Usually you can disable it when you start the car, but it will enable again the next time you drive it. If I turn something off, I want it to stay off.

author: Psi
author_rank: Super Contributor
timestamp: February 08, 2019, 09:54:25 pm
content: To be honest, the default to AC current annoys me far more than auto power off

author: David Hess
author_rank: Super Contributor
timestamp: February 09, 2019, 04:04:49 am
content: Quote from: vk6zgo on February 08, 2019, 10:22:50 amThe Beckman Tech 300 series was rated for 2000 hours. But a lot of modern meters which similar performance are only rated for 150 hours; what is up with that?QuoteThe high speed bar graph might be a consideration and there is a general trend that higher resolution requires higher power.

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2019, 12:39:21 am
content: Quote from: james_s on February 08, 2019, 09:50:04 pmThat’s how the Keysight meters work.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: February 10, 2019, 04:22:55 am
content: Quote from: tooki on February 10, 2019, 12:39:21 amthat's a bit of information which will be considered when getting a handheld DMM again.