Velleman LCD panel for displaying current

Hello Team

Trying to use this LCD power panel from Velleman LCD panel for an Arduino project. We will use this panel to display a current (Up to 3A) on a circuit. Not sure if anyone use this kind of display panel before, just want a quick tutorial on hook up.

Knowing we may need a shunt resistor, if anyone can point us to some info. on such hook up?

Here is the PDF file for the 3-1/2D DIGITAL PANEL METER
http://www.vellemanusa.com/downloads/1/pmlcdpmlcdlpmledpmled5gbnlfresd.pdf

Thanks, BTFDev

Figure 3 in this link shows how to wire the meter and the shunt resistor. Just connect the positive lead of the meter to the V+ position of the shunt resistor, and the negative lead to the V- position.

To calculate the size of the current shunt resistor, use ohms law, and the 200 mV full scale reading of the meter along with your 3A maximum current

0.2V / 3 A = R ~ 0.066ohms

and will need to disipate

W = I^2 * R = 3^2 * 0.066 = 0.6 watts

Of course your not likely to find a 0.066 ohm resistor, so you'll need to comprimise of your full scale reading/precision and recalculate based upon what you can find.

Yes it will work but there might be some issues, I didn't read the data sheet through but there are 2 issues, 1. can the device be powered from the same supply that is being measured (This is really important, if the answer is no then you will have to provide a dc Isolated supply (not grounded or common to the voltage you are measuring or damage to the device will occur. Many of the early devives were based on an Intersil chip that had a 'derived' ground that was 1/2 of the supply above ground and making that point (the 'cold' side of the current sense resistor) more positive than it is will damage the display. And #2. you will have a 200 Mv drop across the sensing resistor... at the lowest current you need to measure accurately the drop might well be rather larger than you would expect.

Doc

Wanderson... I2 X R = 6 X .066 = 0.396 W... ( I found it by examining 6 X 6 =)

Doc

Wanderson... I2 X R = 6 X .066 = 0.396 W... ( I found it by examining 6 X 6 =)

Isn't I = 3A ? so I^2 = 9

Sorry, did I miss anything?

Docedison:
Wanderson... I2 X R = 6 X .066 = 0.396 W... ( I found it by examining 6 X 6 =)

Doc

I=3. I^2=9

There are some things I shouldn't do early in the morning... You are of course right... apparently in my world I2 means I X 2... /...
Thank you for the correction, I apologize to you and anyone else I might have offended/mislead by that Gaffe...

Doc