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ADS1115 I2C communication with Raspberry PI3

August 28, 2017, 4:42 am
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Hello,

 

I am seeking some help here, because I am totally new to I2C protocol. I read the basics, and I also went through the chip manual of the AD module for the Raspberry PI.

I am planning to use some Raspberry PI3 with the following module for analogue signal measurements (the module is connected to the RPi via its GPIO pins): http://wiki.52pi.com/index.php/RPI-ADS1115-ADC-Module_SKU:EP-0076#How_to_wire_up

I installed the driver for the Raspbian OS, and all the Python examples run fine, I measure what I expect: https://github.com/adafruit/Adafruit_Python_ADS1x15

 

I would like to use this AD module via the product "LabVIEW for Raspberry PI compatible compiler - Home Edition" (https://www.tsxperts.com/labviewforraspberrypi/ ). I installed the special image for the RPi, and I can deploy and run fine LabVIEW VIs as *.pyzw files from the RPi linux. There is a subpalette for the I2C functions, I try to use the functions here to create communication VIs for my hobby project:

I2C_subpalette.png

I have attached my VI as a snippet too, plus some more relevant files, like the chip ADS1115 manual (the important pages are 11., 18-19.).

quickstart1.png

I tried to follow the procedure what is described in the section "Quickstart guide", at page 11. However, I am not really sure whether I write to the device registers in the proper manner. The data what I read out from the conversion register, does not seem to be correct (maybe the LSB and MSB should be swapped?). So I guess I must do something or several things wrong... I hope someone could help me how to make a proper I2C programming in this particular case. Thanks!!

...Some more screenshots below:

 

GPIO_I2C_test4.png

 

GPIO_RP_Pi3.png

 

 

 

 

 

 

 

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Acquisition (Scope) saved as TDMS from Labview, why I can't open it with Signal Express 2014?

August 28, 2017, 4:51 am
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Like the subject, I saved a TDMS file with acquisition from scope (waveform data type). If i try to import it in Signal Express 2014 nothing appens. Signal Express seems ok due to the fact that i can open other TDMS file.

 

Any advice?

 

Thank you very much,

 

Francesco

 

P.S.

First time I use the NI Scope hardware. I was able to stream and save 30s of acq with 5MS sampling (I16 Data Type) before memory error, the system is a NI PXI with 4 GB of RAM. Did I reach the system capabilities or I can do better?

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How simulate a digital input?

August 28, 2017, 5:39 am
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Hi, i'm working on a project and i'm going to use an usb-6001.For the present i'm using a simuleted one via MAX, but i dont'know how to change the digital input at will.Any ideas?

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PIC18F4550 USB comunication LabView

August 28, 2017, 6:08 am
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Que tal, necesito ayuda con un problema que tengo, soy nuevo en labview, no se ocmo resolverlo, se supone que el esquema esta bien, pero me marca error en una linea de conexión, les agradecería si pudieran ayudarme, gracias!

 

Hello! I need help with a problem that I have, I'm a biginer programing on labview, I do not know how to solve it, it's supposed to be a good scheme, but I have a problem in a connection line, I'd appreciate it if you could help me, thank you!

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If Switch is on, toggle action/led once.

August 28, 2017, 6:15 am
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I'm trying to make it so that if I turn a switch to the on(true) position, then an led toggles on just once before turning back off. I can't figure out how to have it toggle rather than just stay on. also, I cannot change the action of the switch to only turn on while the switch is being held closed as I need that switch to work with other parts of my code. Any advice?

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Do not see ouput change on the UMFT240XE with D2xx driver

August 28, 2017, 7:36 am
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I use LabvIEW2011 with windows 7.

I installed the drive D2xx for the UMFT240XE (all OK).

 

I connect the device to the USB port.

I see that deice communicates, device description give back UMFT240XE.

I filled in some data in the buffer (00,FF,00).

I put probes and a scope on the I/O pins.

But I can see any data change on the I/O pins. Do I miss something?

See attached the labview example.

 

Kind Regards, Bernard Arts

Does somebody have an idea?

 

 

 

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Simple Event Structure VI, but having issues getting it to work.

August 28, 2017, 8:03 am
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I have an overall pretty simple VI, but it is the first time I am trying to use the event structure and having some issues with it. The signal I am capturing comes from a hand driven wheel. Due to this I do not want to continuously have data being saved. The wheel has a reference encoder inside of it as well. What I would like to do is for every pulse of the reference encoder have labview save the value of the input signal at that exact moment for one full revolution. I've attached my current VI, the left loop just waits for the index to pulse before starting to gather data. Then, the right loop is used for the actual data acquisition. The reference encoder has 8192 pulses per revolution, which is why that is the stop condition. The problem I am having is that when I run the VI the first part works, when it sees the index it switches to the other loop, but the loop with the event structure doesn't capture any data. The array remains empty. I'm thinking I have something not right about the event structure, since I've never used them before, and that is causing the issue.   

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How to fix Error 1148

August 28, 2017, 8:31 am
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USB-8451 and HMC 5883 Magnetometer

August 28, 2017, 9:43 am
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Has anyone used one directly with the 8451 or just with an Ardiuno? Looking for an example to see if it will even work.

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Re: Monthly bugs, August 2017

August 28, 2017, 9:29 am
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I managed to get LabVIEW 2017 to do this:labview bug 1 - Copy.PNGlabview bug 2.PNG

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FPGA Indicators

August 28, 2017, 10:03 am
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Hello all

 

I know in order to optimize the speed the FPGA can run, I need to limit the amount of indicators on the FPGA front panel and use DMA FIFOs where appropriate. Where I'm confused is I am unsure at what data size it is more efficient to use a DMA FIFO. I have 13 indicators in my FPGA code, and am not sure what data transfer mechanism to use. Thanks.

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indicating that the node has not executed

August 28, 2017, 10:26 am
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In LabVIEW, a Boolean actually can be in three states:  TRUE, FALSE, or NOT EXECUTED.  How can I make an indicator that shows that data it is displaying is not yet valid?  

 

Thanks

 

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How to input the words Date and Time into the File Format String?

August 28, 2017, 10:56 am
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So right now I have a VI in which when you click Save it saves the current state of the Front Panel as a Jpeg. That all works fine. But I wanted to automatically save the file as the current date by using -%y-%d-%H-%M-%S. That also works fine. The only problem? When saved the name of the file looks like a bunch of random numbers.

Ex. 2017-08-28-12-54-19. 

 

Technically this is fine. It's correct. But it looks like crap. Is there a way I can modify the File Format String so that the final file reads "Date: 2017-08-28 Time: 12-54-19"?

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Writing chinese and english characters to a file

August 28, 2017, 11:30 am
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Is it possible to combine Chinese and English text in a string and write it to a file? I have a vi that creates an XML file, we want to add support for Chinese characters. I've got the Chinese characters working now but when I concatenate it with English text it changes all the text to Chinese. 

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Using VSA 86900 with Labview 2016

August 28, 2017, 12:51 pm
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Hello,

 

I have a PXA N9030a from Keysight. I have installed the VSA 86900 software onto it. I am trying to get it to communicate with LabVIEW so that i can start coding it for research use. I saw some stuff with using ActiveX to get it to communicate, but when I have them both on I do not see the VSA show up as an item for ActiveX. Is there other ways to get this software to work with LabVIEW?

 

Thanks for any help

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i2c on myRIO-1900

August 28, 2017, 1:48 pm
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Connect a measurement device via Wifi to LabView

August 28, 2017, 2:04 pm
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within a project that I am doing I need to read and capture the data coming from a measurement equipment that sends them through Wifi, I thank you if anyone has a suggestion like I can do it using LabView, the only information that I have is the IP adress of the equipment.

I have basic knowledge of LabView.

 

Thank you

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Re: Serial port issue

June 20, 2017, 11:24 pm
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I am running a program with 6 serial ports working in parallel. I have similar issue of read / write  with RW error sometimes. I am attaching the main VI as well. Can you guide me on this.

 

 

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FPGA VI Optimization

August 28, 2017, 2:39 pm
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I am working on a project utilizing a cRIO 9035 and a full set of c series modules however my FPGA VI is right at the edge of using all of the LUTs available and so most times it will fail to compile with an estimated 103% of LUT usage. I  do not feel that the vi is so complex that it actually should be using that much of the resources so my thought was that my code having been built using modified versions of a couple of the example programs was just inefficient and after reading all of the white papers and tutorials that I could find on optimizing FPGA code I was not making any headway.

 

The purpose of the project is to run 6 9503 stepper drivers along with a 9401 DIO module, and one 9215 analog module (I believe I can run this one outside the FPGA but the code has not been added in any case). I have included a zipped copy of the project and the FPGA Vi in question is right there at the front. If anyone could make suggestions on how I might be able to cut down on resource usage I would be much appreciative.

 

Thanks,

Larry D

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How to AO Square Wave Pulse with Different Amp and Freq after time T

August 28, 2017, 6:17 pm
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Hi,

 

I am trying to AO a square wave pulse using DAQmx with USB-6002. The signal that I would like to generate is as follows:

 

For 1ms, generate 25 pulses of 5V amplitude @ 50% duty cycle. Then, 100ms after that, generate 1 pulse of 0.5V amplitude @ 50% duty cycle. Data is only acquired and logged during the 100ms duration. How to best implement this?

 

I started with a state machine in the test vi (see attached) with counters (might not be necessary) to monitor when the program should move to the next state. My goal is to later use such structure in my main QMH program for the signal generation and data acquisition loop. I understand that my timing and sampling information may be off. I am open to ideas and critiques! Thanks. Smiley Happy

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