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Is this voltage and amp schematic correct?

Discussion in 'General Electronics Discussion' started by Protoncub, Mar 8, 2020.

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  1. Protoncub

    Protoncub

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    Dec 3, 2018
    I created a schematic to measure volts and amps with an Ardunio Nano. I have sent the complete schematic to be made from JCLPCB. While I am waiting, I thought I would show the schematic to you for your approval.

    First I provide power to the female XT60 connector and the output to the male XT60 connector. I broke the circuit with A-Con-Positive and A-Con-Negative connectors which go to the current sensor. The amp output goes to A06. Then I have a voltage divider in parallel which connects to A0. (Looking at the circuit, I probably should have put my voltage divider before the amperage break, but I didn't think it would matter.)
    My question is will this be okay to measure amps and volts? Easyeda gave me a wiring error. Thanks
    V_A Schematic.PNG V_A Schematic.PNG
     
  2. Bluejets

    Bluejets

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    Oct 5, 2014
    You'll need to provide a complete diagram as what you have here, although it might make sense to you, means next to nothing for others.

    It is normally not a good move to get pcb's made until you have at least done a test run with components.

    No idea what you are trying to do with the two batteries in the left lower diagram and in some instances, the battery symbol would be considered as "reversed" from normal accepted symbols.

    There are current sensors out there which suit Arduino and have both current and voltage measuring capability in the one device.
     
  3. Protoncub

    Protoncub

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    Dec 3, 2018

    I'm, sorry you can't read the schematic. I am posting another schematic with lines going from the circuit I am measuring to the sensors associated with it. I assume you know that the signal from the voltage sensor goes to A0 on the Arduino and the signal out on the amp sensor goes to to A6 (it was a typo as A06). The information presented on the drawing should have been sufficient to let me know if it will work or not. My question was: Is the circuit OK for pulling amps and voltage readings?

    Ya got me there, although at $16 dollars for 5 boards including shipping is cheap enough for me to take a risk. Other than the circuit providing the current and voltage, I am using other circuits from sources on the internet that are proven and I have checked it many times.


    Well, I got those part schematics straight out of Easyeda . These are XT60 connectors generally used connecting Lipo batteries to the electronic circuits. The XT60 female is where the battery plugs in. I break the circuit to measure amperage, I connect the voltage divider to measure voltage, and the male plug connects to the circuit that I am measuring. This is what I wanted to know if it will work.


    These are the components I had on hand and wanted to make use of them.


    [Mod edit added quotes for ease of reading]

    I probably was kinda vague on what I was looking for, but I don't need a lecture on the last three points of yours. That is not helpful. V_A Schematic Revised.PNG
     
    Last edited by a moderator: Mar 9, 2020
  4. Nanren888

    Nanren888

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    Nov 8, 2015
    Not much to debate here, sorry. Just googled it, as that's the modern standard for "correct: I guess.
    Your's is the first time, I've seen anyone use the battery symbol shorter line for "+" and longer one for "-". Even my daughter's physics text says it's the other way round. :)
    Generally sticking with convention is safer.
    Sorry, could not really follow what you were wanting.
    Sort of looks as if you have two batteries, back to back, U1, U4, which are directly connected to a current sensor.
     
    davenn likes this.
  5. davenn

    davenn Moderator

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    Sep 5, 2009
    no it wont as shown
    Not only are the battery symbols incorrectly marked, but they also go to the wrong terminals elsewhere
    The positive and negatives are really messed up right across the diagrams
     
  6. Bluejets

    Bluejets

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    Oct 5, 2014
    You did ask for help here and the points I made were directly at the errors/omissions.
    If you cannot handle advice then that is your problem, get a life.

    I am well versed in circuit diagrams and I can assure you I do know how to read circuit diagrams.
    The snippets you presented made little sense, so back to the study books you missed I imagine.

    3 out of 3 I guess this end.
     
  7. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    So only connector U4 has the battery attached, whereas connector U1 does not have a battery attached? Then why show a battery in your "schematic" where there is none? Not only confusing but misleading, isn't it? If there were a battery next to U1 you wouldn't be able to measure the current consumption of ythe attached load by putting the sensor between A-con-positive and A-con-negative because a great deal of current would be served by the battery next to U1. This current will not be registered by the current sensor.

    The ACS758 delivers an output signal with reference to GND. So I assume GND is your system ground, right? But your voltage signal A0 is not referenced to GND, it is floating. Imho a connection between "V-con-" and GND is missing. It is good practice to have a single designated GND in a circuit and also to label all signals distinctively. Using diffferent names (V-con- and GND) for a single signal not only is misleading, it will not be allowed by most design tools (at least in my experience).
     
  8. Nanren888

    Nanren888

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    Nov 8, 2015
    Is this it?

    upload_2020-3-10_5-23-45.png

    I assume that the battery symbols are in fact connectors, U1, U4.
    Your device under test is a battery?
    You plug a battery into either U1 or U4.
    You plan to short the battery to the ACS758 to measure your "amperage"?

    In your diagram it seems both U1 and U4 are in series with the ACS758. Can't quite see what was planned.
    "First I provide power to the female XT60 connector and the output to the male XT60 connector"
    Lost me there.

    The voltage measurement looks to be a voltage divider from the battery in U1 to the A0 pin. Is there a ground missing from the bottom of the divider?
     
  9. Protoncub

    Protoncub

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    Dec 3, 2018
    Well, this is on me, The circuit below is a basic look at what I wanted to know: If it was a good idea to connect both an ammeter and a voltmeter in the same circuit at the same time.
    Simple Circuit.PNG


    The first thing that confused you is the symbol used for the XT connectors that I used for U1 and U4 in the original schematic. I was more interested in the holes for the pcb than the accuracy of the circuit diagram.
    The symbol below is what I should have used instead of the symbol that looks like a battery..
    XT Connector Schematic.PNG
    This s a female XT60 connector. The male connector connects to female connector so I didn't download the picture of the male.

    female xt connector.PNG

    This is the basic circuit with the connectors.

    XT Connector Schematic.PNG XT Connector Schematic.PNG
    So isn't an ammeter connected in series? And a voltmeter connected in parallel? This is what I have done, except that instead of using meters, I am using outputs connected to an Arduino. The device ACS758 is a Hall Effect device that is in series with the circuit and the output pin goes to an analog pin of the Arduino.

    The output between the resisitors in the voltage divider goes to another analog pin of the Arduino. The reason for the voltage divider is that with the values of the resistors , it can read 25 Volts instead of the 5 volts that an Arduino can handle by itself. Now I do apologize for the bad XT60 symbols that I used instead of correct ones, and I have submitted a correction to Easyeda,
    This is what the ACS758 looks like. The large legs are in series with the circuit and the small pins are positive, negative, and signal
    acs758.PNG

    Now Bluejets, the reason I asked if you could read a schematic is that I thought it was obvious that the connectors in the series and the parallel circuit was referenced to the respective sensors. The reason I didn't include the Arduino was since if the amperage and voltage sensor inputs were incorrect, it wouldn't wouldn't work as intended. If the voltage and amperage sensor inputs are correct ,then it should work fine.

    Nanren888,
    >>> The voltage measurement looks to be a voltage divider from the battery in U1 to the A0 pin. Is there a ground missing from the bottom of the divider?
    The voltage divider goes from the positive rail to the negative rail, so it should be connected to ground. Like I said, the voltage divider is part of a circuit that I found on youtube.

    The lesson I am taking from this is to make sure the pars are labeled correctly and that I ask my question in a sensible manner. This is an interesting exercise that I won't attempt again.
    Thanks to all who responded
     

    Attached Files:

  10. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    That's completely o.k.
    You still need to connect the Arduino's ground (GND) to the battery's minus (XT60 pin 1). Otherwise the voltaeg divider's output is floating and you will get meaningless measurements.
    upload_2020-3-10_8-6-43.png
    :):):)
     
  11. Protoncub

    Protoncub

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    0
    Dec 3, 2018
    Thank you! The pcb has a ground plane that should be easy to fix!!!
     
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