How to use DAQmx Read to measure several analog channels
I have two analog inputs using USB 6221 and I want to measure the voltage of each of them. I use vi DAQmx-read and I select input analog, 1 sample, several channels, but I do not know how to connect several channels at the entrance of the physical channel.
For reference - I would recommend ad DAQmx questions here:
NEITHER Forums: Multifunction Data Acquisition
There are several ways to add multiple channels for a fast task-ni.com look for "select multiple channels DAQmx" gives me this like the hit albums:
2X8D7F5Z knowledge base: How can I select more than one channel of NOR-DAQmx LabVIEW?
Hope that helps!
Tags: NI Hardware
recently, I used to download the pdf [link deleted... MOD] to share with friends... but some time pdf size increases its limit and can not download... so can someone tell me how to use adobe reader to optimize pdf and make it smaller... I searched fot optimization option but can not find... so please help me.
Cannot be done with the player. You would need another tool (like Acrobat).
Does anyone know how to use powershell to create data warehouses Fibre Channel?
A text file lists the data warehouse with data store names and sizes (GB) as input:
Version5 VMFS file system
Block size of 1 MB
The script should ignore LUN ID 0 as long as it is not a data store, it's a startup logic unit number.
The value in $esxname is correct?
Do you want to see this name when you
Get-VMHost | Select name
I found reading file express vi measure in LV7.1 does not read from the beginning of the file when you run it the second time. Instead, it resume from where it left off last time. Usually, the user would read the entire file measure each time. So when you try to read the second time, it will show an error window saying that it has reached the end of the file (because he was reading the entire file first).
I wonder how useful to resume from the last stopping point is? Is there a way to start over each time that the VI excute it?
I'm sure that's how reading file measure works 90%. Whenever she is called in a single run of the application, it will start off the coast where it was stopped. You will need to work with the low level screw to get what you want to do.
This Express VI works in a similar way the screws and the following functions:
Read text file
Read binary file
Read the spreadsheet file
File dialog box
Scan to file
And, you can always use the node to set the file Position to set the position at the beginning of the file.
I am still fairly new to LabView, only it uses about 5 months, so bear with me.
I'm trying to understand why the DAQmx playback function runs slower I expect. I use a PCIe-6363 map connected to two BNC-2110 connector blocks. I run the attached code (Position AOM control_prod_cons) and producer while the loop takes about 14 ms to execute. Here's why this is a question:
The Subvi belongs to a larger structure that we use in our research lab to run our system of construction craft nanofabrication. You are using a computer-controlled turntable (wise move task), monitors of reading of the scene (spot monitor sensor) sensor and control a shutter that controls power to the sample (Subvi with lightning) laser. Up to 4 outputs analog and three analog inputs. The scene is being ordered to move in 5 steps of nanometer to a speed of 50 micrometers per second, a rate of analog output of 10,000 samples per second per channel (3 of them). The shutter has a rate much more low yield, at most 5 samples per second. Our goal is to synchronize the movement of the scene with the shutter, and so we must read the exact position of the scene using the analog inputs, one for each axis, x, y and z, vote as often as possible, even if in reality it didn't need to be more than one read each ms.
AOM control_prod_cons position takes two points in space that we wish to move between two points where the shutter must open/close. The first image in the flat sequence did some vector calculations to get the line that we write out the origin of the octant where x, y and z be positive by adding or subtracting, then making reflections around axes, if necessary. The end of x, y and z values (which are now all positive) are summed and placed later in the sequence. Coordinated sensor monitor are then read in (loop producer) and turn the same way coordinates the target have been transformed (consumer loop), then compared with the values of (x + y + z) end and start (0) and adjusted accordingly shutter. (For troubleshooting purposes, "off" is 2.5 and read the text file we entered to extract structure).
All the tests I've done so now tell me that the loop of the producer is the rate limiting step. For a line that is 30 microns long, with the displacement of scene I described above, I was 45 or 46 readings, that works on a read (on the three channels) once all the ~ 14 ms, or only 72 samples per second per channel, which is * very * slow for the card and is not acceptable for our application. Am I missing something? Why the producer loop takes 14 ms per iteration? I tried to reduce the sampling frequency of writing to 1000 samples per second per channel, but that did not alter the reading rate, so I'm not sure I can cela pins on the map.
I ran the DAQmx read function as a NChannel 1sample, read in a while loop like I do in more complicated VI, reading of the three analog inputs in a very simple VI who only reads the sensor monitors and nothing else and the reading rate was 2750 samples per channel (read 5000 samples through three channels in 1800 ms) , so I know that the card can read that fast.
I've also attached the highest lying VI that sets up the physical channels for adding information. I am also attaching a VI where the producer/consumer framework is not used. Also, this while loop took ~ 14 ms to exploit.
Sorry, that was so verbose, just try to do what I'm trying to erase. If you have any other questions, please just ask. Thanks in advance for your help.
Well I'll be darn. The "task AO is?" query seems to be the culprit. I have no memory of being always aware that there was such an expensive application. I don't know if I tried to make such a request in a tight loop before, but I'm a little surprised by the fact that I'm surprised. I don't know if anything is changed, but in case it's a secondary-ish effect, I use the new DAQmx 16.0
Another approach would be to use a property DAQmx writing node to query the Total number of the samples. It seems quite a bit faster.
How can I use develop/Tone/Auto on several pictures at the same time?
Highlighting multiple photos and clicking on it did not work for me, if I can get it to work on a single photo at a time.
- Go to the develop module
- Select the photos in the camera roll.
- Hold down the Ctrl key and click on the Sync button. He turns to auto sync.
- Now, whatever you do develop apply to all photos.
- Click on auto sync once more to turn off autosynching.
- The display of the grid of Goto.
- Select the photos.
- Press Ctrl + U.
I want to use the checkbox to select several lines of af: table
I use a USB6356 to read 5 analog channels (more digital input port A)) simultaneously until you press a stop button. The idea is to represent all the signals captured on a temporal scale after the acquisition.
I am convert and storage of the 2D array that is captured in each iteration of the loop in another 2D array in order to have an output of 5 table lines (one for each input signal).
However, Labview can not handle so much treatment in so short a time table (I think that the main bottleneck is the 2D Transpose VI table) and accidents very soon (I have to kill the entire process and restart Labview). Is there a better way to do this?
See you soon
Your problem is that you have horrible memory management here. Whenever you add in the table, more memory is allocated, then the table is copied. You are basically out of memory.
1. use samples of N, N channels, 1 table D of waveforms for your Read DAQmx
2. change your chart to a chart and move it to be inside the loop. Maintain chart, a story, so you can still see the X last samples on it (1024 by default).
3. save your data in a file. I recommend using the DAQmx configure connection before starting the task. This allows the stream directly to a TDMS file for further processing.
Hello. I have an output of an amplifier which is 10 mV/V, which is read by a USB-6002. This amplifier voltage range is 0 to 200 volts. Have tested the DAQmx create scale Vi, I don't understand how it works. Looked at the other posts here for answers, I still haven't understood how it works. As a first step, it says that it uses the y = mx + b equation for it. I don't know what the slope refers to except if it is the angle of the line. If someone would have an example that explains how it works, it would be great. I also tried to look at an example but could not find one. Thank you
Here is an explanation "improvised" y = mx + b. If you think of 'x' as the input and 'y' as output, then you can consider "m" as the gain, and "b" corresponds to the offset, the output that you can read with zero entry.
If you think of this equation from an amplifier, many are designed to have zero output when there is no entry. In other words, b = 0. If you have a gain of 10 mV/V (which I guess means that a 1V input would give an output 10mV, then m, usually called "the slope" (which is the slope of the curve of output), serait.010/1 = 0.01.)
Note you describe the range of the amplifier as 0-200V, so the output will be 0 - 2V, well inside the ±10V USB-6002.
I have a problem as in the http://forums.ni.com/ni/board/message?board.id=170&message.id=404676&query.id=250408section.
I'm sorry for the repetition of the subject, but I read all your advice and have not yet solved the problem.
My task very simply: I use USB-6251, differential mode to measure battery voltage Energizer 1.5V. But result shows > 10V? Mean.VI shows greater 4V (see attached photo)
I do not understand what happed with my task?
Please help me!
Thank you very much!
Please post on the Forums OR!
How do you have your battery connected? Do you use polarization resistors? This could be a grounding problem and can be fixed if the polarization resistors are used. See table 1 in this document , and the differential configuration for a floating source.
Please I have a site on [link removed by the host of the forum]and I want to convert to pdf format. How can I do I have need of your suggestions and comments.
Adobe Acrobat can convert a webpage to PDF format or by using the browser plugin or the Create button in the Acrobat toolbar.
Adobe Reader provides no conversion or PDF creation tools.
But the location always returns the location of the first. How can I get him back the second occurrence of ' ~' in the string.
Thanks in advance
Published by: user566193 on October 1, 2010 13:35
OK, it's not pretty, but it works... I will describe the step-by-step process.
Getting the first Occurrence
(1) on the column that you want to find the tilda (~), click the fx button.
(2) use the LOCATE function: LOCATE ('~ ', tablename.columnname)
It's will give you the position of the first occurrence of the tilda number.
Getting the second Occurrence
(3) in order to find the location of a string in another string from a set position, you use the same function, but in this format: LOCATE (string1, string2, n)
Note: If you look at the function OBIEE, it says to use LocateN, but actually, it does not work and you will get a syntax error, so use LocateN. Use instead SEE them as I've described, but with the same syntax as in the LocateN function.
Well, in this function, the value of n must be value just after the first occurrence to find the second occurrence.
The first occurrence is determined by the LOCATION feature in step 2, we simply need to 'Add 1' to the obtained position. It turns out however that the result of the LOCATION works, although this property returns a number isn't a number format. Therefore, we have to GET the result as an INTEGER. (Still with me? Good.)
OK, so putting this together, we nest a function LOCATE in a LOCATION feature as follows:
LOCATE ('~ ', tablename, columnname, CAST (LOCATE('~', tablename.columnname) AS INTEGER) + 1).
The above formula will give you the second occurrence of your tilda. You can repeat this step for the third, etc.
I'm new to apex and I have a problem now. I find this code somewhere:
FOR I IN 1... APEX_APPLICATION. G_F01. COUNTING LOOP
REMOVE FROM THE ASER
WHERE ID = TO_NUMBER (APEX_APPLICATION. G_F01 (I));
It can remove selected items, now I want to make some modifications to it.
I want to update some columns when I ticked the box. How to make this change? I mean, like this:
UPDATE ASER SET STATUS = '1' when I selected items
Can you help me? Thank you!
I don't know exactly what you want to do, but if I am guessing right then of course you want updated also based on the elements of the selected check box.
BEGIN FOR I IN 1 .. APEX_APPLICATION.G_F01.COUNT LOOP DELETE FROM ASER WHERE ID=TO_NUMBER(APEX_APPLICATION.G_F01(I)) ; UPDATE APSER SET STATUS = 1 WHERE ID=TO_NUMBER(APEX_APPLICATION.G_F01(I)) ; END LOOP; END;
But if not and you try rather to use these values to update another table after Session State is the way to go.
I try to highlight and make notes on a PDF document. I downloaded Adobe reader. How can I connect my PDFs with Adobe Acrobat reader? Help, please!
To get started on Acrobat Reader for iOS, I highly recommend reading the help documentation.
For annotation tools (point, climax, sticky notes, etc.), please take a look at the section titled "comment, markup, draw.
Please do not hesitate to ask questions in this forum again if something is not clear.
Thank you for the inquiry.
In a Webinar instructor (Chris Orwig) showed how to make multiple adjustments in the base Panel in the develop module. Then, he showed how close the Basic module by clicking the small triangle at the top of the module. The Basic module closed when it made a single control bar and the cursor appears instead. This move allowed the instructor set all previously defined parameters of basic module at the same time. I tried to do. But when I close the base module that no control bar and the slider appear. Any suggestions why this is the case?
I use Lightroom 5.4 and OS 10.9.2.
Obviously, he wasn't in the base Panel, but in the adjustment brush:
By clicking the triangle at the end of the red arrow, you get this:
And there is your cursor effect.
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