topic Re: waveform graph problem in LabVIEW

waveform graph problem

dineshmeena — Fri, 02 Jun 2017 07:42:15 GMT

hi,

i need to display a 16 channel in single graph with channel vs channel 2 or Channel 3 vs channel 6 like any channel vs any channel as x and y plot and user should select which plot sould be seen anybody have idea for this

Re: waveform graph problem

JamesSouv — Fri, 02 Jun 2017 08:37:51 GMT

Hello,
in your request, you mentioned that you have a problem.
could you then please upload your VI so that we could go through the problem together?

Re: waveform graph problem

cbutcher — Fri, 02 Jun 2017 09:45:05 GMT

@dineshmeena wrote:

hi,

i need to display a 16 channel in single graph with channel vs channel 2 or Channel 3 vs channel 6 like any channel vs any channel as x and y plot and user should select which plot sould be seen anybody have idea for this

Presumably at the moment you have sets of 1D arrays of data values. Place these into a cluster then an array, such that you have a 1D array of clusters of arrays of doubles (or whatever representation).

When you choose the sets to plot, index your array with the two values chosen to get two clusters each containing a 1D array of points. Then unbundle and bundle the two together to form one cluster with 2 1D arrays. Wire this to an X-Y graph.

Re: waveform graph problem

jwscs — Fri, 02 Jun 2017 09:49:32 GMT

nice that you finally found the right forum to post questions.

since you are new to labview (i am guessing) please have a look at the training resource suggestions on mentioned top of the discussion forum

https://forums.ni.com/t5/forums/replypage/board-id/170/

if you have SSP then the online training is highly recommended.

another way is, just play with the xy graph/chart, read the context help (ctrl+h and hovering over things) and the full help, and have a look at the examples coming with labview (Help -> Find Examples).

for further questions, please be more specific with what you have, what you want and what your problem is.

regards

Re: waveform graph problem

Henrik_Volkers — Fri, 02 Jun 2017 12:10:28 GMT

here is a quick example .. uses the event structure.. not perfect but gives an idea

you have to change the tones and then the plots to see values on the XY Graph

Uses property nodes to change/update plotnames and the selection text ring etc.

EDIT: Updated the vi, the XY names are now generated ... hope I didn't do all the homework during my coffeebreak 😄

Re: waveform graph problem

dineshmeena — Sat, 03 Jun 2017 10:36:56 GMT

hi sir,

Here i have attached a png file to this. I want to create a Load, deflection and strain curve plot, the first 4 channel is for load and next four is for deflection and remaining eight is for strain, now here i have to make a list of table with checkbox which allows user to see a specific plot in a curve either it is channel 1 with Channel 2 or channel 1 with channel 16, whatever, we should display a graph that we swap it which axis we want either channel 1 in x-axis or y axis we should see that that's all

Re: waveform graph problem

dineshmeena — Sat, 03 Jun 2017 10:50:52 GMT

Thanks a lot good idea

Re: waveform graph problem

dineshmeena — Sat, 03 Jun 2017 13:29:28 GMT

Hi henrik,

The VI you send me works great but i need to select only a particular channel that i need to display in a graph like a .png i just send to you and also i need to display a plot name for x axis and y axis with respect to changes in the plot values

Re: waveform graph problem

cbutcher — Sun, 04 Jun 2017 08:09:20 GMT

I'm writing here in response to a PM and the most recent posts to this thread.

I'm not sure what you're looking for in your image that Henrik's solution doesn't provide. His solution is very similar to my earlier suggestion - form an array of arrays (Henrik used an array of waveforms generated by the Basic Signal Generator) and then index them, and bundle to form a valid input for an XY Graph.

What parts of his solution didn't work for you? Can you be more specific as to what you wanted that his solution didn't provide - it seems to me like all of the things you wanted are included in his code.

You should in particular pay attention to the part in the 'plots: Value Change' case, where the lower graph is updated (XY Graph). There, you can see the automatic indexing of his Plots input - your case will only have one pair, so you don't need a For loop in the simplest case, followed by explicit indexing of the array of waveforms (the brown wire, passed into the for loop from above). He uses the values of the X and Y arrays (you'll just have single X and Y values) to pick out two individual waveforms, then after forming a Plot Label using waveform attributes; these are like a collection of meta-data you can attach to a waveform - you can see him doing this in the first case, '"tones", "sampling info": Value Change'.

After that he takes only the Y component of the waveform (i.e. the data values - the other parts of a waveform are t0 and dt) using Get Waveform Components and uses the Bundle node to place them in a cluster. This is then wired (using autoindexing in his application - no need to worry about that in yours if you don't use a For loop) to the XY Graph directly.

Re: waveform graph problem

dineshmeena — Mon, 05 Jun 2017 04:43:17 GMT

Hi james,

This is it,if you know what to do reply me that create DAQmx read.vi is used to interface with the NI USB 6211 is it correct or need some modification and, of course, it wasn't completed yet.

Re: waveform graph problem

cbutcher — Mon, 05 Jun 2017 06:16:33 GMT

Looking at your VI, it seems you have fundamentally misunderstood my suggestion and Henrik's example VI. You are outputting the same data (the same wire) to a large number of graphs. No matter what you choose, the graphs will all show the same pair. Therefore, there is almost no reason to have more than one graph in the Array: Value Change case. Also, only the labels for XY Graph 17 will be changed. See if you can understand why.

I would strongly suggest reading the links at the top of the forum board relating to learning LabVIEW under the heading Getting Started (or similar). If you have access to a current SSP, then the online training is a very good resource.

Regarding your latest question - yes, the DAQmx Read.vi is the VI you should use to read data from the USB 6211 (or many other NI DAQ boards). There are examples available that show setting up and making analog input acquisitions. To find examples in LabVIEW, click on the Help menu, then select "Find Examples...". You can use the search bar to find appropriate examples. I would suggest any of the "Voltage - ... Input" examples, for example "Voltage - Continuous Input.vi".

You should read the Context Help for each VI in the example (press Ctrl-H to open the context help window if it is closed) and then use only the VIs that you need in your own application. The Context Help is a vital resource to using LabVIEW!

Re: waveform graph problem

dineshmeena — Sat, 10 Jun 2017 13:54:34 GMT

yeah i agree to that but i seriously need some ideas to create a application for load cell strain gauge measurement for the 16 channel daq usb 6211 here 2 channel is for load cell in terms of KN/sec and 4 channel is for measuring displacement caused due to the load forcing on the beam and the remaining channel is to measure a strains caused due to deformation and the output should be displayed in the waveform graph if you want to share some ideas pls reply to this message ASAP

Re: waveform graph problem

dineshmeena — Sat, 10 Jun 2017 13:56:24 GMT

and also i need a control to change the rate of loading

Re: waveform graph problem

dineshmeena — Sat, 10 Jun 2017 14:01:29 GMT

hi henrik the vi you send me it was very useful but at the same time when i was interfacing with external device especially for multiple no. of channels how should i react with it i need a exact solution bcoz i need to submit this project within a week send me the solution if you're willing to...

Re: waveform graph problem

cbutcher — Sat, 10 Jun 2017 15:21:43 GMT

@dineshmeena wrote:

yeah i agree to that but i seriously need some ideas to create a application for load cell strain gauge measurement for the 16 channel daq usb 6211 here 2 channel is for load cell in terms of KN/sec and 4 channel is for measuring displacement caused due to the load forcing on the beam and the remaining channel is to measure a strains caused due to deformation and the output should be displayed in the waveform graph if you want to share some ideas pls reply to this message ASAP

Hi,

I don't understand exactly what you mean. In the post after this one, you talk about controlling the load. Do you have some digital control that can vary the load? Your description of inputs and channels isn't clear, but this question hasn't previously seemed to be about making measurements - only about displaying results in a graph.

If you have a further question about the graphing, please let us know what the further problem is and we'll try to help.

If you have a different question, please start a new thread and describe in detail what the issue is, and again, we'll try to help! 🙂

Re: waveform graph problem

dineshmeena — Wed, 14 Jun 2017 07:14:11 GMT

hi james,

here i have send you a vi analyse it and i explain my project here i need to extract a strain value from the load cell which was used to test the beam for 200kN and also i need to get a displacement value using LVDT like this i need to test for usb 6211 16 channel here 4 channel is for Displacement in mm and 10 channel is for strains in microstrains and 2 channel is for load measurement and i have a control here to stabilise the rate of loading can you explain that and also i should display a xy graph for each channel and every graph should display a plot for each and every channel in x and y axis and also i need to create a listbox for this channel to select which plot is to be displayed in x and y axis if you dont get my last point look at a vi send my henrik volkers like that i need it when it was connected to 16 channel usb 6211 and i was new to this labview and my lecturers want me to finish this task i need your help here. and also looak at the 8 channel application like this

Re: waveform graph problem

dineshmeena — Wed, 14 Jun 2017 07:18:03 GMT

hi butcher,

here i have send you a vi analyse it and i explain my project here i need to extract a strain value from the load cell which was used to test the beam for 200kN and also i need to get a displacement value using LVDT like this i need to test for usb 6211 16 channel here 4 channel is for Displacement in mm and 10 channel is for strains in microstrains and 2 channel is for load measurement and i should display a xy graph for each channel and every graph should display a plot for each and every channel in x and y axis and also i need to create a listbox for this channel to select which plot is to be displayed in x and y axis if you dont get my last point look at a vi send my henrik volkers like that i need it when it was connected to 16 channel usb 6211 and i was new to this labview and my lecturers want me to finish this task i need your help here. and also looak at the 8 channel application like this a

Re: waveform graph problem

dineshmeena — Wed, 14 Jun 2017 07:21:18 GMT

hi butcher,

here i have send you a vi analyse it and i explain my project here i need to extract a strain value from the load cell which was used to test the beam for 200kN and also i need to get a displacement value using LVDT like this i need to test for usb 6211 16 channel here 4 channel is for Displacement in mm and 10 channel is for strains in microstrains and 2 channel is for load measurement and also i should display a xy graph for each channel and every graph should display a plot for each and every channel in x and y axis and also i need to create a listbox for this channel to select which plot is to be displayed in x and y axis if you dont get my last point look at a vi send my henrik volkers like that i need it when it was connected to 16 channel usb 6211 and i was new to this labview and my lecturers want me to finish this task i need your help here. and also looak at the 8 channel application like this

Re: waveform graph problem

dineshmeena — Wed, 14 Jun 2017 10:01:58 GMT

hi henrik

i've designed a vi which it was similar like you but i din't know whether the values plotting in xy graph is correct or not? but finally got this ouput i need you to verify it if it is needed some modification you can text me that actually i designed this vi for the measurement of battery voltage
(AA)using DAQ usb-6008 for 2 batteries which was having different voltage if it is wrong then provide me the solution

Re: waveform graph problem

dineshmeena — Wed, 14 Jun 2017 10:02:53 GMT

sorru here i have the attachment