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looking for best solution to measure DC Milliamps

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johnny78

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I need to measure a DC Milliampere 10 - 2000 mA's
using arduino i've got ACS712 Module
But it seems it cant do this

any better choice guys?
thanks
 
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KlausST

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Hi,

Which method is useful or not depends on your requirements:
* Isolating or not?
* Accuracy
* precision
* measurement range
* voltage drop
* cost
* size
....

The straight forward method is a resistive measurement method.
--> Feed a 1mA signal through a 1kOhm resistor and get 1V.
You are free to use lower ohmic resistors and amplifiers.

Klaus
 

    johnny78

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paulfjujo

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Hello,

**broken link removed** is not the best soluce . I did some comparaison tests with **broken link removed**
wich has better accuracy and big resolution.
This sensor can also measure voltage . Could be insert on High Side ..
 

    johnny78

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johnny78

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Hi,

Which method is useful or not depends on your requirements:
* Isolating or not?
* Accuracy
* precision
* measurement range
* voltage drop
* cost
* size
....

The straight forward method is a resistive measurement method.
--> Feed a 1mA signal through a 1kOhm resistor and get 1V.
You are free to use lower ohmic resistors and amplifiers.

Klaus
the Ina219 module is a good choice i guess
But what you mean by isolating for this kind of measurements?
& when i have tested it on multimeter i didnt measure the voltage drop
So for 5v 100mA Current what voltage drop must i have?
 

danadakk

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Your shunt you use with the INA219 determines output V for a given input current.

Here is a "typical" card, where shunt used is 100 mohm.



This does not have a galvanic isolation capability, but can do sensing
in high side to a CM voltage of up to + 26 Vdc.



Regards, Dana.
 

    johnny78

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KlausST

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Hi,

Without circuit details... it ´s impossible for me to give reliable recommendation.

Answer the questions above. Show a (hand drawn) schematic of what you want to do.

Klaus
 

danadakk

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Whats wrong with the ACS712 solution ? What circuit symptoms are you
seeing ? Why do you say its not working ?


Regards, Dana.
 

johnny78

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Hi,

Without circuit details... it ´s impossible for me to give reliable recommendation.

Answer the questions above. Show a (hand drawn) schematic of what you want to do.

Klaus
its a device to test the Continuity of Internal Coating for Tube
be measuring Current through liquid solution using 5vdc

the measuring range between 20 - 200mA
isolating or not its ok
i will test the Power Supply for voltage drop in the liquid if it helps

thanks
--- Updated ---

Whats wrong with the ACS712 solution ? What circuit symptoms are you
seeing ? Why do you say its not working ?


Regards, Dana.
i didn't test it because no one recommend it to measure mA's

thanks
 
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KlausST

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Hi,

it´s still not clear what and how you want to do.
Why not useing a DVM?

Why no simple sketch?

Why not the simple resistor method?
Why do you (in post#1) say ACS712 module does not work, but then you say you never tested it. And you say no one recommends it ... but youalready excluded it yourself on post#1.

Why do you in post#10 talk about a power supply test .... but no one before.

and so on...

Klaus
 

johnny78

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Hi,

it´s still not clear what and how you want to do.
Why not useing a DVM?

Why no simple sketch?

Why not the simple resistor method?
Why do you (in post#1) say ACS712 module does not work, but then you say you never tested it. And you say no one recommends it ... but youalready excluded it yourself on post#1.

Why do you in post#10 talk about a power supply test .... but no one before.

and so on...

Klaus
its first time working with this kind of circuits

using simple Resistor method you mean by testing Voltage drop after the resistor
by reading its voltage on Analog input

by DVM u mean a volt meter?

i need an MCU to read the current for specified period of time
Hi,

it´s still not clear what and how you want to do.
Why not useing a DVM?

Why no simple sketch?

Why not the simple resistor method?
Why do you (in post#1) say ACS712 module does not work, but then you say you never tested it. And you say no one recommends it ... but youalready excluded it yourself on post#1.

Why do you in post#10 talk about a power supply test .... but no one before.

and so on...

Klaus
Hi

i want to build a device to measure the current flowing through ِِِAluminum Tube which must be coated inside with some hard isolation solution
the idea is to detect the quality of the coating
there must be specified Voltage for period of time
So i need to use an MCU to read the value & display it when test is done

i will test the ACS712 module & reply with the results i get

thanks for your help
 

KlausST

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Hi,
its first time working with this kind of circuits
the less you are experienced the more important that you draw and write down your ideas. A drawing is urgent, not only for us, but for yourself.
Now that we are in post#14 ... I call it laziness. You don't do yourself a favour, nor do you motivate us.

using simple Resistor method you mean by testing Voltage drop after the resistor
Yes. This is the most forward, simplest and most precise method.

by DVM u mean a volt meter?
Yes.

i need an MCU to read the current for specified period of time
We don't know why.
But it seems to be a hard requirement. It is urgent to tell us your requirements. Maybe you know, but we can not read your mind.
A draft ... I don't want to repeat it again.

Klaus
 

c_mitra

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its a device to test the Continuity of Internal Coating for Tube
be measuring Current through liquid solution using 5vdc
i. If you want to measure or test the continuity of a coating inside (or outside) of a tube, then you do not need precise value of the current. You just need to make sure that an appreciable current is flowing.

2. Measuring current through a liquid solution is a completely different kettle of fish. You need electrodes (at least two) to get current in and out and there will be potentials at the electrodes (called polarization potentials) that can affect the measurements. For example, the electrodes can be rectifying (allow current in one direction and not in the other).

3. A voltage measuring device must have infinite resistance because it should not draw any current from the circuit (voltage devices are always placed in parallel to the device). in the same way, a current measuring device must have zero resistance (because current measuring devices are always placed in series with the device) so that it does not have any insertion effect.

You need to be more specific: what kind of tube and what kind of coating?

For example, are you interested in measuring the continuity of the internal coating in a micro channel plate for individual channels?
 

c_mitra

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i want to build a device to measure the current flowing through ِِِAluminum Tube which must be coated inside with some hard isolation solution
the idea is to detect the quality of the coating
there must be specified Voltage for period of time
So i need to use an MCU to read the value & display it when test is done
I do not understand what you are planning to do but.

Electrochemists have studied the effects of painting on corrosion. Painting as corrosion inhibitor is not a new subject. Once it was realized that corrosion is an electrochemical process, electrochemists have studied ways to prevent corrosion on metal bodies by painting. The focus was two fold: improve paint formulations and understand surface preparation (prior to actual painting). No, I am not meaning paintings by van Gogh or Klimt. I mean paints applied on exposed metal surfaces to prevent corrosion by air or water (the elements, in short).

Your focus is apparently similar. But then the design of the experiment to study a particular process is unique in every case and you cannot apply the same tools and techniques for every case. Aluminum is an extremely reactive metal (and naturally protected by a thin oxide layer) and there are lots of work on protecting the exposed metal surface from the elements. You could benefit from a regular literature search. Remember that a proper design of the experiment is key to success and not the details of the measurement of the volts and amperes.
 

    johnny78

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johnny78

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hi Guys
i've purchased INA219 module & i just got it now
facing strange problem if anyone can give me an idea
when i try to compile the sketch in the examples it gives me error
Error compiling for board Arduino UNO

any working example if you have will be great
thanks guys
--- Updated ---

I do not understand what you are planning to do but.

Electrochemists have studied the effects of painting on corrosion. Painting as corrosion inhibitor is not a new subject. Once it was realized that corrosion is an electrochemical process, electrochemists have studied ways to prevent corrosion on metal bodies by painting. The focus was two fold: improve paint formulations and understand surface preparation (prior to actual painting). No, I am not meaning paintings by van Gogh or Klimt. I mean paints applied on exposed metal surfaces to prevent corrosion by air or water (the elements, in short).

Your focus is apparently similar. But then the design of the experiment to study a particular process is unique in every case and you cannot apply the same tools and techniques for every case. Aluminum is an extremely reactive metal (and naturally protected by a thin oxide layer) and there are lots of work on protecting the exposed metal surface from the elements. You could benefit from a regular literature search. Remember that a proper design of the experiment is key to success and not the details of the measurement of the volts and amperes.
thanks for the information
 

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