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Products => Other Equipment & Products => Topic started by: T3sl4co1l on March 19, 2018, 07:31:31 pm

Title: Is it just me or are these DPMs almost nonexistent..?
Post by: T3sl4co1l on March 19, 2018, 07:31:31 pm
Looking for digital panel meter, signed, 4 digits.

Metric shitloads of 3-digit LCD and LED meters.  Cheap from China or elsewhere.  A few bucks, no problem.

They're all 0-255 (well, 0-200 but who's counting?), 2V range, and I have a 0-5V signal to measure.  Ugh. I'd rather get an analog movement.

So it's got to be 3-1/2 or 4 digits, preferably the latter (or better).

Digikey has this:
https://www.digikey.com/product-detail/en/c-ton-industries/DK743/CDPM743-ND/278976 (https://www.digikey.com/product-detail/en/c-ton-industries/DK743/CDPM743-ND/278976)
It's $50.  Let's say I want to spend $200 on DPMs, that only gets me four.  I want four right now, so that's okay.  But I'd rather have six or eight for projects in the immediate future, plus extras in inventory.

A tiresome perusal of Amazon doesn't show anything great from China.  None of them document the most basic things: what the display is (signed or not? half or full digit?), what the input connection is (common ground, or how much common mode range?) and so on.

This one is well documented, I have no problem designing it into a product, sight unseen.

Is it just me or is China actually slacking on a market niche here?

Or, alternately: is Amazon so badly searchable that, they're out there, and I can't find them?

Tim
Title: Re: Is it just me or are these DPMs almost nonexistent..?
Post by: BravoV on March 19, 2018, 07:40:00 pm
Actually alot from China, if you don't mind the below standard documentation, at least better than none though.

Just one example sort by price  >:D out of so many of these 5 digits panel meter -> HERE (https://www.aliexpress.com/item/GWUNW-BY536V-DC-0-33-000V-0-33V-digital-voltmeter-5-bit-high-precision/32838869757.html?spm=2114.search0104.3.26.744b6bf76lekzy&ws_ab_test=searchweb0_0,searchweb201602_3_10152_10151_10065_10068_10344_10342_10343_10340_10341_10696_10084_10083_10618_10307_10313_10059_10534_100031_10103_10624_10623_443_10622_10621_10620,searchweb201603_49,ppcSwitch_5&algo_expid=cb673973-d021-45bb-a0b4-38c212c650c2-3&algo_pvid=cb673973-d021-45bb-a0b4-38c212c650c2&priceBeautifyAB=0)

... and different colors too ..  :-DD

(https://ae01.alicdn.com/kf/HTB1UxRqbdLO8KJjSZFxq6yGEVXaX.jpg?size=753890&height=675&width=900&hash=893c1d482c0796b99207ac74646b4f90)
Title: Re: Is it just me or are these DPMs almost nonexistent..?
Post by: jimmc on March 19, 2018, 08:45:09 pm
Quote from: BravoV on March 19, 2018, 07:40:00 pm
Actually alot from China, if you don't mind the below standard documentation, at least better than none though.

Just one example sort by price  >:D out of so many of these 5 digits panel meter -> HERE (https://www.aliexpress.com/item/GWUNW-BY536V-DC-0-33-000V-0-33V-digital-voltmeter-5-bit-high-precision/32838869757.html?spm=2114.search0104.3.26.744b6bf76lekzy&ws_ab_test=searchweb0_0,searchweb201602_3_10152_10151_10065_10068_10344_10342_10343_10340_10341_10696_10084_10083_10618_10307_10313_10059_10534_100031_10103_10624_10623_443_10622_10621_10620,searchweb201603_49,ppcSwitch_5&algo_expid=cb673973-d021-45bb-a0b4-38c212c650c2-3&algo_pvid=cb673973-d021-45bb-a0b4-38c212c650c2&priceBeautifyAB=0)


I've used a couple of similar devices from ebay. Surprisingly accurate but only work for positive inputs.
Input resistance is around 300k.

Jim
Title: Re: Is it just me or are these DPMs almost nonexistent..?
Post by: T3sl4co1l on March 19, 2018, 08:45:59 pm
Are those signed?  They don't look signed, and don't say so.

Ed: I see these look to be signed,
https://www.aliexpress.com/item/YB5145B-LED-Digital-DC-Voltmeter-4-1-2-Voltage-Meter-display-Tester-dc200mV-2V-20V-100V/32849928205.html (https://www.aliexpress.com/item/YB5145B-LED-Digital-DC-Voltmeter-4-1-2-Voltage-Meter-display-Tester-dc200mV-2V-20V-100V/32849928205.html)
and even notes that the inputs are common ground.

There are about six other listings (in three stores?) for the same basic device, with varying ratings (poor translation).

The only other types in the listing are,
https://www.aliexpress.com/item/Four-and-a-Half-Digital-Voltmeters-Digital-Indicators-20V-200V-Four-wire-Precision-DC-DC-Voltmeter/32857126357.html (https://www.aliexpress.com/item/Four-and-a-Half-Digital-Voltmeters-Digital-Indicators-20V-200V-Four-wire-Precision-DC-DC-Voltmeter/32857126357.html)
which seems to be pretty similar but shorter, and
https://www.aliexpress.com/item/High-accuracy-0-56-Red-LED-display-DC-voltage-meter-voltmeter-can-test-positive-and-negative/32319712361.html (https://www.aliexpress.com/item/High-accuracy-0-56-Red-LED-display-DC-voltage-meter-voltmeter-can-test-positive-and-negative/32319712361.html)
this KETOTEK thing, which might well be the same.

Is this really it, in the world?

Tim
Title: Re: Is it just me or are these DPMs almost nonexistent..?
Post by: BravoV on March 19, 2018, 08:49:54 pm
Like this -> HERE (https://www.aliexpress.com/item/YB5145AI-DC-Isolation-Voltmeter-4-1-2-LED-Digital-Voltage-Meter-5-Bits-200mV-2V-20V/32857137129.html?spm=2114.search0104.3.1.7e04614cD7ycpV&ws_ab_test=searchweb0_0,searchweb201602_3_10152_10151_10065_10068_10344_10342_10343_10340_10341_10696_10084_10083_10618_10307_10313_10059_10534_100031_10103_10624_10623_443_10622_10621_10620,searchweb201603_49,ppcSwitch_5&algo_expid=24c88e3e-5258-4590-87b0-019bf6521c81-0&algo_pvid=24c88e3e-5258-4590-87b0-019bf6521c81&priceBeautifyAB=0) ? , again, sort by price.  :P

(https://ae01.alicdn.com/kf/HTB1vedIn9YH8KJjSspdq6ARgVXao.jpg)