I'm wondering if anyone has any experience with ambient temperature sensing. I know you can monitor the temperature of the Zynq chip and that there's the extension board that the Grove temperature sensor is compatible with, but I'm looking for something more compact. Perhaps something that can be installed on the main board? Apologies if this is a naive question!

I am using the impedance analyzer extension board already, so both of my input channels are in use.

Thanks,

Addie

Statistics: Posted by arlederman89 — Wed Jun 28, 2017 8:52 pm

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Recently I am researching the chip--MSP430FR5969 and I bought one from site which produced by Texas Instruments. And I would like to ask two questions,maybe they are simple for you.

1). Is there EEROM in MSP430FR5969 inside?

2). If I want to write data inside and keep data exist even in the mode of power-down. They can be written,read or erase. Where can I put the data?

Thanks for you guide in advance!

Statistics: Posted by ana — Mon Jun 19, 2017 9:36 am

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I'm curious if there have been any developments for the LCR Meter calibration and/or compensation. Has anyone done this? I would like to calibrate the device and do open/short and cable extension compensation as well. Any advice would be appreciated!

Thanks!

Cheers,

Addie

Statistics: Posted by arlederman89 — Fri Jun 09, 2017 5:43 pm

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This time, I ordered from www.pcbgogo.com/b. It always in the first page of google. maybe it is reliable.

I received pcbs last day, it seems well made and high quality.

Who wants to see picture, can contact me at ruby.940801@gmail.com

Statistics: Posted by Ruby Xiang — Mon Jun 05, 2017 10:49 am

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It seems to be only ~$1500 ?

The company: www.pcbgogo.com/b

Or contact me: ruby.940801@gmail.com

I am familiar with their copmpany.

Statistics: Posted by Ruby Xiang — Mon Jun 05, 2017 10:35 am

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I am relatively new to all things electrical engineering, so bear with me, please! I am working towards taking impedance measurements of a piezoceramic using Red Pitaya and the LCR meter extension module. I understand how to use the hardware, but I am curious if there is a block diagram type schematic like the one here: http://redpitaya.readthedocs.io/en/latest/doc/developerGuide/125-14/shem.html for the main board to see how the LCR meter hardware works.

Also, does the LCR meter make measurements using the automatic balance bridge method? As a two-, five-, or four-terminal method?

I'm also not sure how to connect IN1 to ground. Can I simply use an alligator clip on the SMA connection and attach to a power supply ground port?

Finally, are there SCPI commands to remote control the LCR meter and impedance analyzer? I cannot seem to find them in the documentation, and the LCR meter script I did find looks like it works in the PC's command line.

Thank you for any help!

Cheers,

Addie

EDITS: I was able to figure out that it is a 2T auto-balancing bridge method device and how to use MATLAB to use the command line to run the lcr program. I would still be interested in a schematic of the extension board and more information about grounding the IN1 terminal.

Statistics: Posted by arlederman89 — Thu Jun 01, 2017 8:32 pm

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assembly circuit

Statistics: Posted by LulaNord — Thu Jun 01, 2017 6:29 pm

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Hi,

I recommend you either fork / clone the RedPitaya github repository or download the contents as a zip archive. Within that, the folder "fpga" has all code that is used to build the fpga logic.

But ... with the 0.94 ecosystem release, a proper project file for the Vivado GUI is no longer included. This means you'll have to do some preparations to work with the project in Vivado. Nothing too complicated though, just do the following:

- edit the file fpga/red_pitaya_vivado_project.tcl and change the line Code:into
`read_verilog .srcs/sources_1/bd/system/hdl/system_wrapper.v`

Code:`read_verilog project/redpitaya.srcs/sources_1/bd/system/hdl/system_wrapper.v`

- start Vivado, at the bottom of the main screen you have the "Tcl Console"
- use the tcl console to navigate into the fpga-folder with the command "cd" (on my machine it would be "cd /Users/Nils/Documents/RedPitaya/fpga")
- execute "source red_pitaya_vivado_project.tcl" in the tcl console and watch while Vivado magically builds the project

Hi Nils,

i already fork https://github.com/RedPitaya/RedPitaya

but in the file fpga/red_pitaya_vivado_project.tcl , i did not found

Code:

`read_verilog .srcs/sources_1/bd/system/hdl/system_wrapper.v`

Statistics: Posted by amin — Tue May 30, 2017 2:55 am

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I have been using an RP with an aluminum case and I am now at the stage to daisy chain with another RP. I was amazed to find that I can't do that with the expensive aluminum case but I can with the plastic one. So I will have to revert to the plastic one or use a drill and hacksaw to make an opening in the metal one.

Thanks.

Statistics: Posted by JohnnyMalaria — Wed May 24, 2017 8:09 pm

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It will fit but you need to have correct thickens off the thermal pad.

recommended thickens is 2mm.

Best, Zumy

Statistics: Posted by redpitaya — Fri May 19, 2017 10:04 am

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Fast analog inputs are not differential i.e they have common ground.

But not sure if I understand this question: "I have to use them both at the same time."

You can use them at the same time, just inputs are not differential.

Kind Regards, Zumy

Statistics: Posted by redpitaya — Fri May 19, 2017 10:01 am

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Will a 3M 14mmx14mm thermal pad fit for the aluminium case?

I am not really sure about the dimensions of the Xilinx Zynq 7010 SoC and i do not have my pitaya with me to measure it at the moment.

Thanks in advance for your help!

Best regards,

Dim

Statistics: Posted by mitsoyba — Tue May 16, 2017 11:17 am

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I want to use Red Pitaya's (v 1.1.1) analog inputs as a DAQ device for measurement of a few things on a DC/DC step up converter. I wanted to use LabVIEW, and will have to use them in HV setting. The main question is are the inputs differential? I have to use them both at the same time.

Best regards

Statistics: Posted by marin268 — Thu May 11, 2017 4:34 pm

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you must be sure to have well defined setup and on that setup you define the crosstalk levels.

So, I think that correct way of measuring crosstalk for example

between OUT1 and IN1 is:

1. OUT1, OUT2 , IN1, IN2 are all terminated with 50OHM. OUT1 and OUT2 are designed for 50Ohm.

2. OUT1, OUT2 amplitudes are set to 0V.

3. Acquire signals on IN1 and calculate FFT. When calculating FFT you need to use correct equations for calculating dB.

4. Save this FFT "trace" as "noise_fft"

5. OUT1 amplitude is set to 0.7V (don't use max amplitude in order to avoid non-linearities of DAC)

then you make freq. sweep for OUT1 frequency - from 100Hz to 50MHz.

6. For each f. step of OUT1 acquire signal on IN1, calculate FFT -> you get "cross_talk_FFT(f.step)"

7. for each f. step subtract "noise_fft" from "cross_talk_FFT(f_step)"

8. plot all "cross_talk_FFT(f_step)" one above another. (don't average them!!!)

8a. instead of 8. you can pick up max values for each f.step from "cross_talk_FFT(f_step)" matrix.

with that you will extract worst cases.

9. When you start STEMlab board start Oscilloscope application and then close it.

This will load fpga filter parameters.

then you can go with SCPI and remote control.

Now, when doing acquisition you should allays have same sampling rate in order to get

correct FFT calculations.

Preferably you should use max sampling rate.

But if you wish to look at lower freq. range you can use lower sampling rate

and repeat steps from 1-8 while max OUT1 freq is limited by Nyquist.

"I am still not sure how the coupling works ... I also tried to connect 47nF to the +3,3V to ground on the connector, but that did not have any visible effect on cross coupling. My idea was that a ripple on the supply might cause this."

- Yes, power supply ripples and ground plane can affect outputs performances.

but I think this will not affect crosstalk noticeably.

https://ln1985blog.wordpress.com/2016/0 ... rformance/

This is the reason for step 4. exclude environment noise form crosstalk measurements.

The code bellow is for calculating power noise using FFT.

When dealing with amplitude ratios your FFT equations will look different

In equation 1 (look at code) you should use magnitude of complex value and not complex conjugate multiplication

Amplitude spectrum in volts RMS = sqrt(2)* mag(FFT(A))/N

in our case

Amplitude spectrum in volts RMS = sqrt(2)* mag(xdft_hann)/N

and equation 2 should look like

A= 20*log10( Amplitude spectrum in volts RMS/OUT1 amplitude);

Code:

`%% data - acquired signal in volts `

Fs = 125E6;

t = 0:1/Fs:1-1/Fs;

N = length(data);

freq = 0:Fs/N:Fs/2;

R_load=50;

%% Hann window;

w = hann(N)';

K = 64;

tmp = hann(K)/K;

tmp = fft(tmp);

tmp = tmp.*conj(tmp);

dcspan = sum(tmp(1:K/2)>1e-6)-1;

win_gain = sqrt(sum(tmp));

xdft_hann = fft(data.*w)/win_gain;

xdft_hann = xdft_hann(1:N/2+1);

%% Equation 1

Pmag_hann=(xdft_hann.*conj(xdft_hann))./(N^2); % Calculate power spectrum to Fs/2

Pmag_hann = Pmag_hann./R_load; % Calculate for 50 Ohm

%% Equation 2

Pdb_hann = 10*log10(Pmag_hann); % Power in dB 1W as reference

PdBm_hann = 10*log10(Pmag_hann./1E-3); % Power in dBm 1mW as reference

Best, Zumy

PS 1: Double check the new equations for amplitude - I didn't test it

PS 2: A lot of people use same equation for FFT spectrum calculation and then getting wrong results.

mag(a+jb) is not equal to (a+jb)x(a-jb) (complex conjugate)

Statistics: Posted by redpitaya — Thu Apr 20, 2017 11:58 am

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Probably in this cases (amplitude difference) board is not calibrated.

With calibrated board if you set OUT1 to 900mV

connected to IN1 (using 50OHM termination) you should get on IN1 = 900mV +- 0.5mV

Kind Regards, Zumy

Statistics: Posted by redpitaya — Thu Apr 20, 2017 10:57 am

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