Volt/Amp meter from ebay, need help with wiring. And I have pictures of my progress so far!

Discussion in 'The Projects Forum' started by Hamlet, Oct 28, 2015.

  1. Hamlet

    Thread Starter Member

    Jun 10, 2015
    100
    2
    I looked thru the forum, but nothing l could apply.
    The volt & amp meter has 5 wires, two for isolated
    supply, and three for measurement. It's rated for
    30v, range 100v/10A. Built in shunt.

    I also have some pics of my progress on this supply so far...
    I'll share those too. I'm using a heatsink from a scraped
    Mercedes Benz. Transformer came from an industrial yard,
    it ran a hydraulic pump for a truck weigh scale. The front
    panel is from an old road sign.

    Anyway, I'm close to getting this done, but ran into this snag.
    I posted earlier in the following thread. I have the schematic over there
    for those who are curious.

    http://forum.allaboutcircuits.com/threads/flyback-diode-aplication-for-linear-power-supply.116881/
     
  2. pwdixon

    Member

    Oct 11, 2012
    488
    56
    You need to get the actual specs/schematics for the meter, I did try looking this up on ebay but I didn't find it.
     
  3. dl324

    Distinguished Member

    Mar 30, 2015
    3,250
    626
    My guess is that the 2 terminal connector is for power. I see some wires in one of the photos. If they're for the panel meter, colors will give you clues.
    • power leads: black=GND, red=power
    • 3 lead: black=GND, red=voltage, other=current
    If you have wires for connecting to the panel meter, post (smaller size) pictures -- better information yields better guesses...

    Did you try contacting the Seller??
     
    Hamlet likes this.
  4. Hamlet

    Thread Starter Member

    Jun 10, 2015
    100
    2
    The seller responded, and sent me a link for a word.doc of the wiring
    schematic. Unfortunately, it is in chinese language, sigh. I will follow
    this post with google translate. Here is the
    download link. The file is prohibited from upload to this forum:
    116.6.104.5:801/yks/s/029cdded

    ☆ ☆ basic properties
    The module name current and voltage measurement accuracy of 0.1% the display module
    About 200ms refresh rate display mode once double three 0.28 "digital tube
    Measuring range 2A / 5A / 10A / 50A / 100A (current) measurement range 0V-100V (voltage) minimum display 0.01V
    Operating current of less than 10mA display color red blue
    Storage temperature -10 ℃ to + 85 ℃ splitter Specifications 50A / 100A / 75mV
    Weight 20g external dimensions 48 * 29 * 26mm (LWH)
    Features:
    ★ This module uses two high-quality digital LED manufacturing, high brightness, and can display the current and voltage.
    ★ This module uses imported MCU sampling and display current and voltage, and the software has been a lot of data processing, the display precise and stable.
    ★ This module is fully patch technology, superb technology, while ultra-small size.
    ★ This module has reverse polarity protection, even if it will not reverse damage to the module.
    Instructions
    ★ supply terminal and the ground terminal of the ammeter measurements using common design, that is, the power supply ground terminal and ground test is the same, so the test can only end ammeter in series with the electrical after (ie test between a negative electrode and the DUT power supply equipment)
    ★ recommend header supply end a separate isolated power supply
    It must first access circuit before ★ splitter and then followed by a digital ammeter using high pressure to prevent damage to the meter head.
    Access shunt circuit must first before using digital ammeter head then followed to prevent damage to the high pressure header.

    Lead Definition ( 5 lines)
    Thin black line : Header negative power supply
    The Thin Red Line : Header supply positive ( red line between fine and thin black line voltage 4-30V, than will burn )
    Thick red line : measuring positive voltage input ( voltage wires and a thick black line which is between the voltmeter shows )
    Thick blue line : measuring the current flowing into the lead .
    Thick black line : the measured current flowing lead ( thick black line and the thin black line is common ground , it is communicating )
    Wiring Diagram

    upload_2015-10-28_7-12-45.png

    upload_2015-10-28_7-13-23.png


    ☆基本属性☆

    模块名称

    电流电压显示模块

    测量精度

    0.1%

    刷新速度

    大约200ms一次

    显示方式

    双三位0.28"数码管

    测量范围

    2A/5A/10A/50A/100A(电流)

    测量范围

    0V-100V(电压)最小显示0.01V

    工作电流

    小于10mA

    显示颜色

    红色 蓝色

    存储温度

    -10℃ 到 +85℃

    分流器规格

    50A/100A/75mV

    重量

    20g

    外围尺寸

    48*29*26mm(长宽高 )

    产品特点:

    ★本模块使用两个优质的LED数码管制造,亮度高,并且可以同时显示电流电压。

    ★本模块使用原装进口的单片机采样和显示电流电压,并且在软件上进行了大量的数据处理,使显示精准,稳定。

    ★本模块为全贴片的工艺,工艺精湛,同时体积超小。

    ★本模块具有反接保护,就算接反也不会损坏模块。

    使用方法

    ★本电流表的供电端与测量端的地线采用共地设计,也就是说,供电电源的地线与测试端的地线是相通的,所以电流表的测试端只能串在用电器之后(即被测设备的负极与被测设备电源的负极之间)

    ★建议表头供电端采用单独隔离供电

    ★使用前必须先将分流器接入电路然后再接数字电流表头以防高压损坏表头。

    使用前必须先将分流器接入电路然后再接数字电流表头以防高压损坏表头。


    引线定义(5根线)

    细黑线:表头供电负极

    细红线:表头供电正极(细红线和细黑线之间电压为4-30V,超过必烧)

    粗红线:测量正电压输入(这根线和粗黑线之间的电压就是表头显示的电压)

    粗蓝线:测量电流流入引线。

    粗黑线:测量电流流出引线(粗黑线和细黑线是公共地,是连通的)

    接线图

    =
     
  5. Hamlet

    Thread Starter Member

    Jun 10, 2015
    100
    2
    The doc has 5 schematics, but only two of them are isolated supply.
    I have extra hand windings on my transformer for fans, indicators, &
    instrumentation. An independent supply for the meter usually returns
    better accuracy, so that's my plan. I guess my brain fart is that all of
    the supplied schematics show an external shunt, where my unit has
    the shunt built in. I guess there are several
    models of this meter available.

    The two small gauge red/black are for the isolated supply. I got that.
    The three large wires are red/black/blue. I'm guessing the thick red
    wire will goe either before, or after my output fuse on the positive supply,
    the black wire will go to the supply ground, and the blue wire will go
    to my negative banana jack on the front panel. Does that sound right?
     
  6. dl324

    Distinguished Member

    Mar 30, 2015
    3,250
    626
    But you never mentioned that you understood that... I'm still not very proficient at mind reading...
    Why guess? The document you posted gives the connections.
    • Red = positive output terminal
    • Blue = negative output terminal
    • Black = internal ground
     
    Hamlet likes this.
  7. Hamlet

    Thread Starter Member

    Jun 10, 2015
    100
    2
    You don't have to be snippy, dl324.

    Nevertheless, I feel confident with your reply,
    and I'll give you the kudos.

    Much thanks, hugs, & kisses!
     
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