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Preview: LabVIEW

LabVIEW topics



LabVIEW topics



Published: Tue, 19 Sep 2017 19:36:10 GMT2017-09-19T19:36:10Z

 



How to get Excel Workbook CustomDocumentProperties?

Tue, 19 Sep 2017 18:45:35 GMT2017-09-19T18:45:35Z

Anyone knows what is the datatype returned from this property node?

(image)

 




NI TB 4330 Terminal block doesn't appear in MAX - Unsupported accessory when using MAX

Tue, 19 Sep 2017 18:31:33 GMT2017-09-19T18:31:33Z

Dear all, 

 

 

We have just bought a brand new terminal block NI TB 4330 (to replace the damaged one) which is mounted on a NI PXIe 4331 for a PXI 1073.

 

I have run the VI with the brand new terminal this morning to run two load cells. It worked, I stopped the VI, I run it again and it didn't. I have run the VI 20 times and it didnt work. It says 'unsupported device' is presented. I turned the PC off then turned it on again. The TB NI 4330 terminal block was not appeared in MAX. Can someone tell me how the terminal can be viewed in MAX and what is wrong with this issue?

 

P.S. The bridge module NI PXIe 4331 passes the self-test in MAX.

REgards, 

 

(image) (image) (image)

 




Controls for Single Acting Pump

Tue, 19 Sep 2017 18:20:35 GMT2017-09-19T18:20:35Z

I am currently trying to create a control program using LabVIEW for a single acting pump.  The current vi attached generates a 5VDC signal to open and close a relay.  I currently have a 12VDC power supply wired to the normally open terminal of the relay.  The 12VDC is used to power the pump.  I now want to add code that analyzes load cells and uses a user input to determine when to start our current routine.  Currently it operates on a push of the relay button.  I want it to start when the pressure transducer readout is less than the set value (constant) I determined (this is used to prevent the pump from overloading) AND when the load cell values are less than the user input.

 

For example:

1) If the user wants a 200lbs load applied with the pump to a specimen, he or she enters 200lbs in the load cell input field.

2) If the current load analyzed by our NI9237 module is less than the user input in step 1 then send a signal to start the 5V routine attached to this post.

3)  When the desired input is achieved we want to stop the 5VDC signal attached.

 

Any help would be appreciated!




Ajuste automático del panel de control a la pantalla en vi ejecutable

Tue, 19 Sep 2017 18:00:17 GMT2017-09-19T18:00:17Z

Moved to another board



Is it possible to interface with an FPGA VI on a PXI target using something other than LabVIEW?

Tue, 19 Sep 2017 17:41:13 GMT2017-09-19T17:41:13Z

Hello!

 

I have a setup that consists of PXI-1036 chassis with a PXI-8108 controller and a 7851R FPGA card in it. There is also a host computer (PC) that I use to run the VIs on target. My problem is that the project codebase is a nightmare to support. I inherited it from another person, I already spent over a month on the refactoring, and I feel that LabVIEW is just not the best choice of the environment for this project. For this reason, I want to move the part that runs on the PC to something else, like C# or Python. I want to keep the LabVIEW code on the FPGA primarily because it makes the DMA transfers and reading/writing variables easy.

 

The question is, what is the best way to interface the new code and the LabVIEW FPGA code? 

 

Here is what I've been able to come up with so far:

1) There is a NI library that allows to interface C code with the LabVIEW FPGA, so the most straightforward solution would be to set up an RPC server that supports the basic FPGA functions on the chassis controller and call them remotely.

2) It seems that the chassis controller is already running an RPC server (so that the LabVIEW can run the VIs remotely). It would be great to connect to that with say C# code, but I couldn't find any documentation or libraries for doing so.

3) There is a "VI server" and "Web server" options in the properties of the chassis controller, but again I couldn't find any documentation and libraries for using those.

 

Could you please offer any suggestions on the best way to approach it?

 

Thank you!




does the database toolkit still require runtime license?

Tue, 19 Sep 2017 16:33:00 GMT2017-09-19T16:33:00Z

Just noticed that the database connectivity toolkit is part of LV Professional.  I seem to recall this was a separate product, with a deployment runtime license fee.

 

Is that still the case or is it now free if developed with LV Pro?




IMAQ Merge Overlay issue

Tue, 19 Sep 2017 14:08:26 GMT2017-09-19T14:08:26Z

Hi folks, have had this issue for sometime and cannot get to the bottom of it.

 

I have an image which I'm doing some work on, namely, drawing a region of interest (just a series of lines and a rectangle using the IMAQ Draw subVI).  After doing this operation I use IMAQ Overlay Text and then IMAQ Merge Overlay to burn text metadata into the image.  My output image is mostly correct, in that the text does indeed appear on the image, but my ROI lines disappear and my ROI rectangle becomes a different color.  When I comment out my Overlay Text/Merge Overlay code the ROI looks correct on my output image.  What is Overlay Text/Merge Overlay doing to mess with my program?

 

I have toyed with what goes into the 'Image Dst' input for the IMAQ Merge Overlay subVI, thinking that might be the issue, but haven't gotten anywhere concrete.

 

Image one - With Merge Overlay edited out of code.  This looks correct.  

(image)

Image two - With Merge Overlay in code.  This looks incorrect.  Notice many lines are missing.(image)




Format data from Rs232 connection Newb questions

Tue, 19 Sep 2017 13:58:26 GMT2017-09-19T13:58:26Z

Basically put this is my data;

4.2,30.9,968.8,1816,18/09/17,14:41:49
4.5,30.9,968.8,1814,18/09/17,14:41:59
.... ect.
The goal is to display this on screen in rows/columns and perform some very basic math between readings and then averaging readings.
next step. expert to excel 
Data is separated by commas.. I was thinking 2D array but I'm open to suggestions. 
 
Can anyone one help a newb out?
Thanks
 



Programming for separation of modified 10 Hz TTL pulse

Tue, 19 Sep 2017 13:21:01 GMT2017-09-19T13:21:01Z

I am using photoelastic modulator (PEM) which generates 50 KHz pulses which were down modulated to 10 Hz pulses for circular dichroism (CD) purpose in gas phase. In CD, left circular polarized (LCP) and right circular polarized (RCP) light have to be taken into consideration. Since CD=LCP-RCP. I am trying to develop a program called R2PICD. I am too new to write any Labview program. Here, I am briefly providing information what I want to do so somebody can help me.

10 Hz pulse after down modulation is used to trigger the delay generator which is further dived into two 5 Hz pulses (output channels A and B). After providing certain delay of few microsecond (e.g. 5 µs in channel A and 15 µs in channel B of delay generator), these two 5 Hz pulses were recombined into channel C, which is called modified 10 Hz pulse. This practice has been done to get alternate LCP and RCP pulses.

This modified 10 Hz pulse is used for triggering the pulsed ns laser. This laser beam will interact with molecules in gas phase after passing through polarizers and PEM to generate circular polarized light. Let’s assume that, laser scans from wavelength 500 nm to 501 nm with step width 0.01 nm. The number of steps will be 100.  At 500 nm, if 32 pulses coming from laser is considered then 16 pulses will be of LCP and 16 pulses will be RCP in LCP-RCP-LCP-RCP----manner. Then it is required to take all RCP in one domain and all LCP will be in another domain. Next, CD = ΣLCP – ΣLCP at 500 nm. Then wait for some time to move the grating by 0.01 nm. Repeat the same procedure for 500.01 nm and wait again to move grating and so on. Here after interaction with molecule, it will generate amplitude for each pulse. Amplitude should get for alternative pulses.

In brief, I am interested in 1) separating alternative pulses of modified 10 Hz pulse in two separate domain as LCP and RCP precisely. 2) I want to have amplitude value after interaction of laser beam with molecule.




Adding image in combobox ?

Tue, 19 Sep 2017 12:07:07 GMT2017-09-19T12:07:07Z

Hi,
I can to Add an image in combobox in LabVIEW?
example:
(image)

Thank you, 




Hardware and NI MAX problems

Tue, 19 Sep 2017 11:26:18 GMT2017-09-19T11:26:18Z

Hi,

 

I have problem with my hardware.

when I plug in my DAQ (NI 9184 with Ethernet cable), I don't have access to test my DAQ.

the picture is attached.

(image)




niimaqdx.dll is missing

Tue, 19 Sep 2017 09:48:36 GMT2017-09-19T09:48:36Z

Hallo,

yesterday I had the problem that my IMAQ toolbax was not visible -> https://forums.ni.com/t5/LabVIEW/no-IMAQ-or-IMAQdx-toolbox/m-p/3690255#M1037738

after solved the Problem I went home. This morning, however, when I try to use a tool or open a example I get the message niimaqdx.dll is missing or imaq.dll is missing depending on which tool i use.

 

I use LabVIEW 2016, I installed 17(64bit) which does not support realtime, so I dont use it.

 

(image)

best regarts

Kevin




Error "1172" When calling .net assembly

Tue, 19 Sep 2017 09:32:18 GMT2017-09-19T09:32:18Z

 

Dear Community,

I am working on a program I got from a colleague.

I have a simple init vi referencing a constructor in a dll located in the same path as the vi (the path is under c(image) . I get Error "1172". I have another vi referencing the same dll but now located in another path (still under c(image) . That works fine. Now that the other dll is in memory init.vi runs fine. I can not explain this behavior!

 

LabVIEW 2015

Win 7

Microsoft .NET framework 4.7




pump control using liquid level sensor

Tue, 19 Sep 2017 09:20:19 GMT2017-09-19T09:20:19Z

Hello There.

 

I am, new  with this software. i am currently carrying out a project in school which is explain as follow;

 

1. am using controller  6211

2. pump

3. Pressure sensor

4. two point liquid level sensor

5. I need to be able to turn on and off the pump using the two pont signal from the level sensor. in this case

my maximum signal is Zero(o) and Minimum signal is ( 19)

6. i need to be able to measure the pressure input voltage and convert to PSI

7. I will like to introduce delay so that the ON and OFF process will not be frequent, to prevent tank from damage

8.Since its two point signal   only,  i want to find away to generate data that will cause the tank liquid to increse or decrease as liquid level varies

9.I need to be able to write the pressure  values ,save  in excel or any format

Lastly i want to be able to intialize the VI with a start button after i click on the left hand top run arrow.

 

I attached what i have done so far. it can only turn ON  and  OFF the pump, not very accurate

 

 

Please help.!!!!!

 

Thanks

Amy

 

 




VISA communication with PIC32MX470 USB RAW , HID device

Tue, 19 Sep 2017 07:41:30 GMT2017-09-19T07:41:30Z

Dear all,

 

it's been a while I am struggling with this topic, so please help me.

 

I want to communicate with a device using VISA. The device has a PIC32MX470. I used the NI VISA wizard to create the .inf file and succesfully installed it. the device is recognized by NI MAX. In the properties, I see that there is no BULK IN pipe, so when I try the basic VISA write and VISA read, I am able to succesfully write to the device but I cannot read using the VISA READ as there is no bulk in pipe (please see screenshots).

 

I see the solution in this topic :

https://forums.ni.com/t5/Instrument-Control-GPIB-Serial/VISA-RAW-FOR-USB-USING-PIC18F4550/m-p/3677211#M75469

 

but the engineer who wrote the firmware code for our device says that this solution is not working for us. 

I am wondering if I can only use the USB Interrupt function to read since the BULK IN pipe is not enabled to this kind of PIC, or if it is just  a firmware problem in the uc not detected and the above post is the right solution... If I have to use the interrupt, using the LV example, I receive a timeout error... 

 

Please help me to solve this topic... 




What is the best approach for passing large clusters?

Tue, 19 Sep 2017 04:27:10 GMT2017-09-19T04:27:10Z

Hi All,

I am relatively new to labview and developing a test automation.

For the purpose of this automation I need to read a row of data from a csv which can grow to 250 elements. I have a state machine that goes through a few states, and takes measurements and adds to that data another 200 elements. Ideally I would have used one cluster to pass the data between the states with a shift register but in this case the list of the elements doesn't fit on my screen. I can use a cluster of clusters but I would end up with two many bundle/un-bundles to the get to my elements. I know about global variables but also have heard a lot against using them.

 

It came across my mind that I can use a reference to the big cluster(450 elements) that is memory efficient and also easy to bundle/un-bundle and doesn't clutter my diagram with wires.Is this a good approach?

Any good suggestions are appriciated but bear in mind that I want to keep it simple.

 

Thanks very much




Trouble myRIO Personalities: Default is the only option

Tue, 19 Sep 2017 01:37:04 GMT2017-09-19T01:37:04Z

Hello,

 

I'm amused with the possibilities myRIO can provide, but I have a issue that I can't handle myself.

 

I need to acquire an analog signal and plot it, applying the Fast Fourier Transfor (FFT), but when I used the express VI to read this signal, I've got a DBL value, not a dynamic data.

 

I've reading and found that there are two  high-speed analog data access (which could help me delivering dynamic data), however I need to use the myRIO high-throughput personality and it isn't avaible for choose when creating a new FPGA project on labview.




RE: Problem with Changing the string indicator's text and color

Tue, 19 Sep 2017 01:02:46 GMT2017-09-19T01:02:46Z

 Hi All,

I can't figure out what I am missing here:

I have a state machine with idle > test > report > idle flow. I need to set the front panel string as blank(empty text + gray) when the start button is pressed in the idle state and either (pass + green) or (Fail + red) in the report state. For some reason assigning a color to "text.BGColor" doesn't work, see attachments (sorry can't post the code, it's work). What am I doing wrong?

 

Thanks

HN




A bug caused by turning debugging off...

Mon, 18 Sep 2017 23:30:58 GMT2017-09-18T23:30:58Z

Ok, the attached file demonstrates a problem. The input string driving a "Format into String" node not contain any formatting codes. Consequently when it executes, it returns an error as it should -- unless you turn off debugging. As soon as you do so the error magically disappears. To make it reappear all you have to do is wire an indicator to the formatted string output, and it has to be an indicator, wiring it to the edge of a structure is not good enough.

 

Mike...

 

PS: don't try to figure out why I am doing this. The VI is a much stripped down example to show the problem.




Saving multiple Modbus reads to a csv file

Mon, 18 Sep 2017 23:09:29 GMT2017-09-18T23:09:29Z

Hello,

The attached VI deals with reading and writing a plc and load cell conditioner. The loadcell output (server1) writes to file very well except is tab separated and I would prefer coma. I would really appreciate some advice how to incorporate the other reads and get them all on one line, comma separated with time stamp. There will be a while loop, of course, around the whole scheme to keep it running. One problem I frequently come across is that the data types are wrong for whatever VI I try to add.