Multiple channels on graph

Hi, I am trying to display 2 2-D arrays on 1 graph. I found many examples on the forums that seemed to be what I was looking for, but I just cannot get it to work.
Can anyone maybe make a example (LV 7.0) of displaying 2 2-D arrays one one graph?
Thanks a lot!
Ryan
Ryan
LV 7.1

Here's an even simpler way
Message Edited by altenbach on 06-03-2005 11:57 AM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
2ChannelGraph.png ‏3 KB

Similar Messages

Display multiple channels on waveform graph

Hello,
I would like to display multiple channels of acoustic data on one waveform graph. I currently have them separated and controlled by tabs inside a case Structure. I sometimes have run into DAQ error because I'm looking at 10 channels of 1/3 Octave data real-time. I woundering if I display all the channels on one waveform graph would I elimnate this error.
can anyone help?

Philip,
I'm acquiring data at 44KHz sample rate and my frequency range is 0-20kHz (2 ni-4472 DAQ cards). Since I been using LV (off and on now for about a year) my application is still in the development stage. I tried including pics but could only include 1 at a time, so heres a copy of my vi for you. There is several things I'd like to figure out, I'm viewing data real-time and writing data to file. However, as I'm writing data to file I don't want the data to display in real-time (I think this is where my problem is). The other issued is when I've stopped writing data to file, the case structure outside the while loop opens the file and processed the data, however I'd like to see the data in the same display (waveform graph in while loop). Take look and give me thoughts.
R/Scott
Attachments:
Submarine DAQ_writing reading OFFLINE_Rev2.vi ‏829 KB

Reading multiple channels for multiple graphs

Hey I am fairly new to Labview and am using it just temorarily. My project is to take in readings from a Gaussometer (X,Y, and Z axis) and graph them in read time. The Gaussometer outputs a DC Voltage equal to the gauss of the magnetic field. The X,Y,Z all come in on three differnet channels. Connected to a NI USB-6009
I know I can use the Express> DAQ Assistant, however that outputs "Data" and I was hoping to use this in an Array. So I used the DDT to Array to convert it to the Array format that I needed (thanks to the forums for the help there). My only problem is that I don't know how to do this with multiple channels at the same time. But I have possibly been going about this all wrong.
So I just wanted to know if I could get some help on how to read multiple channels and write to them to three different graphs in real time that would be of great help.

Whether or not you use the Convert From Dynamic Data or the Split Signal, your data should be shown as soon as the DAQ Assistant returns. How you format the data is irrelevant. If the number of samples you request is greater than the sample rate, then it will take longer to acquire the data and there is nothing you can do about that except reduce the number of samples and acquire in a loop. You can append new data to old and display everything in a graph if you want.

Data acquisition from multiple channels.

Hello
Right now, I am able to acquire the signal from a single load cell and display it.But I would like to know of how to acquire acquire signals from two load cells simultaneously.I am using Labview 6i and I am using AI S-Scan with AI config to acquire the waveform.It would be of great help if you could suggest a simple method to acquire the signals.
PS: Please find the attached file used for acquisition from a single load cell.
Looking forward for your reply.
Manasa
Attachments:
test 4.vi ‏102 KB

Hi Manasa,
If I understand what you are trying to do, it is relatively
straightforward to configure your application to acquire data on two channels.
I was unable to run your vi as it was missing some of the subVI’s
from your application. However, your
attachment was sufficient to see what you are trying to do.
Here is how to add channels:
1.
In the I/O Channel Constant, you can add
additional channels by using a comma or a semi-colon. For example, to scan the first four channels
you would put 0:3 in the constant (see attached screenshot ChannelConfig.jpg). To scan the first and third channel you would
put 0,2.
2.
The AI Single Scan VI will now read from
multiple channels. Often it easiest to
configure the output of this VI for viewing by first putting the data into an
array using the Build Array VI. It can
then be plotted in a waveform graph. (see attached screenshot ReadtoGraph.jpg
and WaveFormGraph.jpg)
Just a few notes about “simultaneous” sampling:
Most of the NI data acquisition cards have a multiplexer
between the various input channels and the Analog to Digital (A/D) converter
creating a very small delay between each channel (usually ms range or
smaller). NI does make several data acquisition
cards that can perform true simultaneous sampling, meaning that there is an A/D
converter for each channel.
For the large majority of applications, the small delay
between channels is negligible.
Jared T.
Attachments:
ReadtoGraph.JPG ‏21 KB
ChannelConfig.JPG ‏288 KB
WaveFromChart.JPG ‏61 KB

Multiple channel sampling and write file

Hei,
I wrote a interface which is supposed to allow me to plot multiple channel and write all those datas in a file ; The problem is that :
1- not all the curves are plot in my graph (in fact just one is ploted).
2- At the same time it write in a file but after some times it stoped due to an error : buffer size...related to the offset.
I have attached the vi, I don't understand exactly where those problems are comming from and how to solve them easily.
Thanks for the help
P.
Attachments:
project.vi ‏207 KB

Hi thanks those tips. In fact I had solved those problems mentionned above ; I have alomst finish my interface except that I am trying to write all my datas in a file , in column (all channels) and create a first column at the time (maybe from the sampling time). The problem is that I don't know the output fomat of the "analog 2D DBL" vi and it seems that my way of writing datas time step per time are not right. have you already see this kind of used (analog 2D DBL)? I am using a PCI-6229, and DAQmx 7.3 Drivers
Thanks for your help
P.
Attachments:
project_acquisition.vi ‏338 KB

Acquiring Analog Input from Multiple Channels in Labview

Hello,
i am working on a VI where i need to acquire signals from multiple channels in Labview using NI-9129.Initially i want to acquire contineous input signals (voltage and current) and display it on the graph.
Having looked at forum and Labview examples i tried to make an initail VI but i am not sure if the setup i made needs any modification to serve my purpose.I am fairly new to Labview software.
All i want is
1.To acquire conteneously current and voltage
2.Display current and voltage individually on the graph.
3.Perform some basic calculations like MAXIMUM,MINIMUM and AVERAGE values of voltage and current.
4.Log the data into excel file
I have attached the VI i made so far.i need abit of advice if i am moving in the right direction or not.
Thank You for having a look at my question.
Attachments:
Voltage-Current VI.vi ‏81 KB

Engr_tech wrote:
i think i already have the tdms for data logging.as far as the tdms data logging is concerned,when i enable the logging mode to "read and log" the data logged inside the excel sheet would be seperate for current and voltage.?
Is it practically possible to acquire data from 4 different channels and plot them.if yes,then am i right to assume that all i need is to modify the current VI for four channels having all of them in parallel.
Yes, you are logging directly to a TDMS file. This is definately the best route for data logging from a DAQ. The currents and voltages will show up as different channels in the same group.
To add more channels, just add them to your DAQmx task. The logging will handle it with no issue. Your calculations will also a little work to add the extra channels. Same for the graphs, since you are using seperate charts.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Select multiple channels for one task - control and shift keys don't work

Hi,
Following advice from several other posts, I'm trying to select multiple physical channels from the dropdown list so that I can then use the "unflatten channel string" function later on. It looks like if I hold down either shift or cntrl I should be able to select multiple channels from the list, however, this doesn't work for me. I tried going into the "key navigations" property for the task channel control but it doesn't have any associations listed. Has anyone else come across this and found a fix? I have previously got around this by stating multiple channels with a colon (eg. ai1:3) but this doesn't work for the unflatten function.
Thanks,
Claire.
Solved!
Go to Solution.

Thanks for your reply Dennis, I see what you mean, unfortunately that doesn't solve my problem so I'm missing something else. I've attached my VIs. I expected that the output from the unflattenstring block would be an array of either the channel references or the names I had given them, and that therefore the "array size" in the 4th pane would be "9" (equal to the number of channels). Instead the output is a an "unnamed task#(some number)" when I look at it with a probe. Perhaps I'm misunderstanding how the task naming works?
THanks,
Claire.
Attachments:
Analog SW Trigger_v3.vi ‏33 KB
Cont Acq&Graph Voltage-Analog SW Trigger_cfjv3.vi ‏64 KB

Multiple channel AI measurement in the same module with synchronised AO

I am using NI -9172 for measurment. I am trying to mesure two AI voltage signals on the same module (NI9215).A sinosoidal analog input voltage is generated using NI 9263. The AI and AO are synchronised using Ai start trigger signal from NI 9263( AO). While I can measure an AI signal using the same module, it does not show any measurement signal when I try to modify the VI program for multiple channel measurment. I don't see any kind of error in the program. ( At least the program does not show any kind of errors) Can anyone please tell me what my problems are? I have attached the VI below.
Attachments:
modified Magnetstriction.vi ‏96 KB

Hi
When you say it is working for one channel do you mean that if you enter either one of the inputs among Magenetic Flux or Strain you can see both the input and the output signals? I noticed that you have two DAQmx Create Virtual Channel VIs. They are connected to each ohter and to the same array. This essentially translates into the signal being shown in one graph. For learning more on using multichannel programming please refer to Multi Device Sunch--Shared External Convert Clock.vi. Hope this helps.
Ipshita C.
National Instruments
Applications Engineer

Sme device multiple channel different bridge

Hi
I am using NI 9219
I have input from three different channel configured in different bridge mode with internal excitation.
I am able to acquire signal from each channel individually,
But I am not able to acquire data from all channel from a single vi an display them in a single graph.
Please help ASAP
Thnx
Ravinedr

Hi Revinedr,
It sounds like you are probably trying to run multiple analog input tasks at the same time. You can only run one of these tasks at a time. You can set up your task to include multiple channels with different bridge configurations, just set them up sequentially with the Create Virtual Channel VI.
Message Edited by PBear on 06-20-2008 12:53 PM
PBear
NI RF
Attachments:
multiplechannelbridges.gif ‏5 KB

Measuring Multiple channels at a time

Hello All,
I am new to Labview trying to measure voltages and currents from a
synchronous generators using LabView7.1 abd PCI-MIO-16E-4. I want to
measure all the three phase voltages all at a time so that I can see
the phase difference between them. I modified an example for my purpose
but it can measure only one channel at a time.
Anyone please look into my file and modify it for multiple channels.
Thanks in advance
Venkatgill
Attachments:
Cont Acq&Graph Voltage-Int Clk.vi ‏330 KB

Let me explain. Your board has a single A/D. There is a mux that rapidly switches between channels. It will take a sample from channel 0, then channel 1, then channel 2, and then start all over again. It will repeat until the total number of samples that you requested have been taken. The switching is very fast - on the order of usec, so you can take the 3 measurements but it is not truly simultaneous. Depending on the frequency and the accuracy of the phase difference you're looking for, this may not make a difference. You can also get the inter-channel delay and compensate for it.

Turn off a single plot of a multiple plot waveform graph

I have a multiple plot waveform graph (4 plots). I want to turn off one of the plots, say plot 2. Is this posible from the graphs property node? The property node seems to only give a reference to plot 0. I am using labview 7.
Cheers,
Wayne

I think you can use "active plot" together with "plot.visible"
property node to control which one you'd like to display. By default,
the property node refers to plot 0, but you can change to plot 1 or
other plots by changing active plot property node. You can search
"Plot" in LabVIEW Help if you'd like to know details.
Good luck,
Jian
On 18 Feb 2004 03:28:49 GMT, [email protected] (Computerman74)
wrote:
>>
>>I have a multiple plot waveform graph (4 plots). I want to turn off
>>one of the plots, say plot 2. Is this posible from the graphs
>>property node? The property node seems to only give a reference to
>>plot 0. I am using labview 7.
>>Cheers,
>>Wayne
>>
>>
>>
>>
>>
>>
>
>I would love to know if this is possible. I have been trying to figure i
t out
>myself.
>There is a way to turn a single array off and that is what I am doing for now
>untill this is possible. The plot is still there but reads zero when tunred
>off. It would be cool to have the abillty to turn off a single plot.
>I have tryed all the property nodes with no luck. The answer may be in the
>array size but I can't seem to control that either.
>For now you can use wire all 4 channels using the comparison select. Use a
>constant of 0 And wire up a swtich. When the input is false the output is zero
>in effect making the plot inactive but it still there.

DAQmx Create Multiple Channels

I have downloaded the NI Bridge-Continuous Input Program and am trying to modify it slightly to allow for multiple Wheatstone bridges to be connected. Currently, it has the option to connect to a single channel but not to acquire information from multiple channels simultaneously. All of the information in terms of shunt calibration, bridge information, and waveform graph output will remain the same. Ideally, the program will show the largest value in the final waveform graph but it's fine if it shows separate graphs for each of the two inputs. I have been playing around with it without much luck although if I start from scratch and use the DAQ assistant I am able to get the information without trouble. Any help would be much appreciated.
Solved!
Go to Solution.
Attachments:
Force Measurement.vi ‏96 KB

Actually you are 99.99% of the way there.
You just need 4 characters
The Name filtering on that control is even properly set to allow multiple selections so just shift click the second channel
Jeff

Programatically select Multiple Channel

I am using LabVIEW 7.1, Diadem 9.1.
1)
I have created one Report layout. In which I will have one sheet with 2 2D - Graphs on that. I want to pragamatically set multiple channels for both the graphs. Using the script I could able to set only one channel to the graph.
Please guide me how could I set multiple channels? (Attached Report Layout and Script File, Both uses Example.tdm)
2)
I want to call this script file from the LabVIEW and want to pass channel names as parameters. How could I do it?
Thnaks.
Attachments:
Diadem_test.zip ‏4 KB

Hi Vishal.,
You have a couple of options if what you want to do is transfer a list of desired channel names from LabVIEW to DIAdem. The first option is to write that list into a file and tell DIAdem to read it. There are plenty of different ways of doing this too. The second option is to dynamically send the array of strings to a new DIAdem text channel. The third option is to dynamically send the array of strings to a DIAdem string array.
Any of these options will work fine, and it's really personal preference which you choose. As of DIAdem 9.1, its OLE Automation Server has no dedicated method to pass either a text channel or a string array with one pointer. So you either provide the values one-by-one to a new channel or new DIAdem string array, or you use file I/O. Below you will find an example of sending values one-by-one to a DIAdem channel. This is not a good method for very long channels (>> 1000 rows), but it should be adequate for your described needs.
Regards,
Brad Turpin
DIAdem Product Engineer
National Instruments
Attachments:
DIAdem Text Channel IO.zip ‏78 KB

How do I read multiple channels at one time using labview with the Fluke Hydra Data Bucket 2620a using serial port?

I need to take a reading of 15 channels about once a second. I can read one value at a time using the monitor function on the read values.vi driver, but this takes forever to read all the channels.

I don't have this instrument but I took a look at the instrument driver and it appears that you can only configure one channel at a time to read from. You might want to take a look at the command set for this instrument and see if it allows for configuration of multiple channels. It could be that the instrument driver just doesn't have that built in.
J.R. Allen

How to Read from multiple channels

Dear Sir
I am acquiring data using FP-RTD-122 using OPC Client software. I ahve made one socket for that and i am using command
CWDataSocket1.AccessMode = cwdsReadAutoUpdate
CWDataSocket1.URL = "opc://localhost/National Instruments.OPCFieldPoint/FP Res\FP-RTD-122 @1\Channel 0"
CWDataSocket1.Connect
v = CWDataSocket1.Data.Value
where v is a variant type.But this is 8-channel RTD so how can i read values from all channels using single socket connection Because at presnt i have to use 8 sockets for all eight channels.

At least as of FieldPoint 4.0 and earlier (I do not know about 4.0.1 or later), the OPC Server did not support multiple channel analog items. Thus to read all eight channels of a FP-RTD-122 module, you would need 8 separate socket connections. For discrete modules (boolean), the "All" tag, is treated as a single 8 or 16 bit number.
Regards,
Aaron

Multiple channels on graph

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