Measuring power for iMX6 board using PicoScope 6

tejas1502 · Post by **tejas1502** » Thu Sep 12, 2013 3:41 pm

Hello Everyone,

I am trying to measure the current and voltage on the same screen
for iMX6 Sabre SD board. For measuring voltage and current I have
PicoScope 2204, MI007(probe) and PP264(60 AC/DC Current Clamp).
Now for test run, I connected one end of probe to the scope and
was using the head part to measure voltage at the power source.
I expected it to be 5V but I am getting a plot that is very bad. I
am attaching the screenshot, unfortunately it wasn't allowing me
to upload the screenshot directly as the size of the image was greater
than 256KIB, so I have attached a zipped version. Can anyone please tell me a good
way to measure the voltage other than this?

Admin Edit: I have included the picture for you

[The extension bmp has been deactivated and can no longer be displayed.]

Second, I am trying to measure the current at the same point(power source)
for testing initially. To do these, I attached by current clamp to the
probe and other end to the scope for viewing. So as soon as I get a voltage
reading, it can also give me a current. But on the Picoscope 6 software, it
shows me voltage where I have the current probe connected to measure the
current. I don't know on what should I change to make scope show me Amps as
the measuring unit instead of Volts while I am measuring current.
I looked at a answer to another post on measuring the current and tried to create
a custom probe as it said but that didn't work.
So, can anyone please tell me a way to change the settings or add something
to show me correct current measurement value in Amps on picoscope software?

Thanks
Tejas

Post by **Martyn** » Fri Sep 13, 2013 11:03 am

When you say measure at the power source exactly what do you mean, and where are you connecting ?

The picture is showing a 20ms repetition, or 50Hz cycle, which is mains related.

tejas1502 · Post by **tejas1502** » Fri Sep 13, 2013 2:33 pm

Yes, that is correct.
This graph is mains related.
I placed a tip of the probe at mains for testing and placed current clamp on probe to measure
the current of the voltage measured by the probe. Basically as I have the voltage plot for the mains
shown in the plot, I want to have current plot right below it for the mains.

tejas1502 · Post by **tejas1502** » Wed Sep 18, 2013 1:16 am

Can anyone please help me?
I am not getting any reply.
It is very urgent.

Post by **Martyn** » Wed Sep 18, 2013 6:17 am

Surely this is a DC powered board, it has a 5V/5A DC power supply.

To measure the current you would need to clamp round the positive power wire coming directly into the board from the supply, possibly wrapping it a few times through the jaw to improve sensitivity. For voltage are you probing this wire or power pin on the board ? if so that mains noise on the trace will cause problems, and I would be surprised if the board powered up.

Warning please stay clear of mains when using a 2204 and the MI007

tejas1502 · Post by **tejas1502** » Wed Sep 18, 2013 7:55 pm

Currently I have connected a breadboard wire between the probe and the mains
and I have connected a wire from the probe's ground to the ground on probe.
The DC voltage and current value I am getting are ~1.246mA and ~5.2V.
The only problem I am having is that I have to keep on holding the wire to ground
on the board until measurements are performed. Since I want to be able to take
a measurement for long amount of time, is there a way I can attach the wire to ground
besides soldering it to that point. I am not being able to attach a picture here.

tejas1502 · Post by **tejas1502** » Wed Sep 18, 2013 8:01 pm

Re: Measuring power for iMX6 board using PicoScope 6

Quote

Post by tejas1502 » Wed Sep 18, 2013 8:01 pm

board.jpg

Post by **Martyn** » Thu Sep 19, 2013 9:46 am

Can't see the image, it doesn't appear to be attached or uploaded to the post. Remember to use the upload attachment under the edit box and then when uploaded use place inline to insert it at the appropriate point in the text