ADS1298ECGFE-PDK: Differences between documentation calculations and software output

Hi,

What might be your signal source? Do you have an ECG simulator? It's suggested to use an ECG simulator with the EVM.

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For "As you can see in the first image taken from the user manual compared to the result obtained by doing the test on the software we have that Lead 3 and aVR are reversed, how come?"

Please check the electrode polarity connection and whether they go into the Positive(non-inverting) and Negative(inverting) terminal properly.

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For "For Lead 3 and aVR leads the results are identical to those in the software, while for AVL and aVF leads we can see that the waveform are the same, but the scales are different"

Not sure what you are asking exactly, especially the description/phrase "the same", are they 100.00% the same or 99.9% the same? How do you quantify?

Note/Remember that all the ECG leads are vector/directional decompositions from the primary/principal ECG vector/direction, so some could be very similar and some could be very flat and some could be inverted; depending on the primary/principal ECG vector magnitude as well as how electrodes are placed and connected.

Please do some study about the ECG signals, leads and vectors.

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And, FYI, the default EVM and GUI are setup in the way 

CH2 is Lead I = RA-LA
CH3 is Lead II = RA-LL
There is no raw signal available/shown for Lead III = LA-LL = Lead II(RA-LL) – Lead I(RA-LA) = LA - LL.
Lead III(LA-LL) is calculated/derived from Lead II(RA-LL) – Lead I(RA-LA) = LA - LL

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Thanks

For the first question, we did not use electrodes to perform the test but software test functionality so without the electrodes attached.

While for the second question, we used a Fluke Prosim 2 simulator to generate the signals, unfortunately the software only pulls out the 8 channels and not the leads so I am not able to compare 1 to 1 values but I see that the scales of the values are the same in the first two cases and different in the third and fourth.

Hi,

Would you please clarify what you mean by "the result obtained by doing the test on the software"?

The GUI works with the EVM, how did you get the signals to show on the GUI?

Thanks

We performed the test indicated in the user manual:

With this input configuration

Hi,

Please see if you can follow the following screenshot and get the similar plot- don't worry the plot is not exactly the same as the test signals is changing/toggling from negative to positive with some period, so whether you see the waveform starting from positive or negative is depending on the moment when you click the Acquire(i.e. start sampling/acquiring).

Thanks

I get the same result as you, but it is different from the user manual, because in the case of the manual for Lead 3 there is a flat line, do you agree with me?

User manual may use different settings and didn't enable all channels.

As long as you get the same plot as the one shown above, it's good to go.

Thanks

Okay thank you, for the other question however do you have any way to help me understand? Can you generate some input data and show me the right calculations to compute the derived derivations?

Hi,

I don't understand your question clearly, would you explain a bit more?

And, I also see another question requested from you coming from one of our FAE, so where do you want me reply?

It's more communication efficient if we can stay in one thread for similar topic or question.

Thanks

These are two different topics, so if you can answer both of them, you would be doing me a great favor.
In this case after purchasing an ECG signal from our Fluke Prosim 2 simulator with your software we exported the data generated from the 8 channels and tried to calculate the additional leads (LEAD 3, aVR, aVL, aVF), in the case of Lead 3 and the aVR lead by graphing the results we can see that the y-axis scales are the same, while in the case of the aVL and aVF leads the values in the y-axis are different, the formulas we followed are these:

The software unfortunately doesn't allow the output of these four leads so you can't compare them, so I wanted to know if we were doing the calculations the right way

Since the other request has been closed I have to add it here.

I would like to connect the ADS1298ECG-FE to a custom device of mine via SPI, keeping the power supply from MMB0.

To do this, I have disconnected the ADS1298ECG-FE and MMB0,
I connected the power supply PINs to J4 (and verified that the power supplies were correct via the TPs).

I connected the SPI PINs from J2 to my custom device as in the picture:

But despite this, I cannot get a response from the sensor.

Is there anything else I need to do on the EVB? Jumpers to change or cables to connect?
Could you explain to me how to do this integration with my custom device via SPI?

Thank you.

Hi,

Here are some guidance.

Please let me know if you could connect RL, RA, LA and LL from ECG simulator to EVM and obtain the following in GUI?