Subset of channel

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• Selection of a subset of channels to read with DAQmx

  Hello

  I use a 32 channel NI9205 analog input module, connected with the chassis OR cDAQ-9174 and LABVIEW 2011.

  I created a task in the measurement and Automation Explorer who has 16 analog input of virtual channels (each of them with her has an entry configuration, scale, calibration, etc...). Inside LABVIEW, I opened this task to acquire some data, but I just want to read some of the 16 channels (defined by the user), not all, so before the "time DAQmx", I put a 'DAQmx reading node' and I put the ChannelsToRead with the names of the channels that I want to read. It seems to work, but when I put the acquisition rate it's error.

  The acquire module supports a rate of 250 kHz (divided by each channel). So if I put 5 channels to read, for example, it should work with a rate of up to 50 kHz. But whenever I try to use an acquisition rate higher than 15 625 kHz (which is 250 kHz/16) I get an error that says that the maximum rate is 15, 625kHz. As if I was using 16 channels of the task, but I'm not...

  Here the screenshot of channels read and sync configuration.

  Thank you
  Alexander

  Hello Alexander, and welcome to the forums,

  As odessy27 says that you do not reach the correct sample rate because the task is to be set up to read 16 channels; in spite of you more later by specifying which channels are to read.

  To preserve the configuration settings of your created able task and Automation Explorer (MAX), I recommend creating global chains of these. A Global channel will store your configuration for each physical channel and can be accessed from multiple tasks

  Creating a Global channel by the physical channels in your task of MAX right-clicking and then selecting create Global Channel. .

  You can drag these through to your block diagram and wire in the task/channels in the terminal of a function of mx-acquisition of data, as shown in the image below.

  If you change to a control by right clicking > change control channels can be set by the user and the maximum purchase price will go as planned.

  Concerning

  Jamie

• If I use a few channels on PCI-6259 to increase the sampling rate, channels numbers can I be contiguous?

  We are looking to buy a card PCI-6259 usable on a Linux machine. We would use NIDAQmx to access the card. If we were to use only a few channels to increase the sampling rate, do I need to select specific channels?

  For example, the card is 1 MHz. If I select the channel 1 and channel 2, I can taste each channel at 500 KHz. could I choose 8 channel and channel 13 and still be able to sample each channel to 500KHz? Or need of specific channels to use when a subset of channels are selected?

  Thank you

  -Tom

  Thanks for the quick response.

  -Tom

• Sampling rate 9172 OR cDAQ

  I am using a cDAQ 9172 with modules NI 9219, NI 9264 and three NI 9211.  I'm looking to acquire signals out of the acquisition of data within a loop under continuous sampling.  My program works fine if I set the number of samples to read 1-2 Hz, but I need to go faster than that.  If I change the sampling rate, the loop is executed at this speed but sensors still read only in samples at 2 Hz and then duplicating over and over again.  I was wondering if it was possible to read on 1 sample at the time of the acquisition of data at a faster rate.  I know that the frequency of sampling on the sensors and data acquisition are much higher than that.  1 sample at the time of the Board of Directors has the limitatioins of being only able to run at 2 Hz?  Please let me know

  Thank you

  Craig

  Hi Craig,.

  I don't know exactly what you describe. Are you feeding the DAQmx Read output in an express VI? Or are you using the express VI DAQ Assistant for the analog input task?

  If you use the DAQ Assistant, you can set the ADC synchronization mode without changing your code:

  

  If not, use the 'Active channels (if subset)' property to control the subset of channels on which your VI defines AI. ADCTimingMode.

  For example, the following code snippet creates 8 virtual channels named myVoltage0 by myVoltage7 and sets HAVE them. ADCTimingMode on myVoltage4 of virtual channels through myVoltage7. These are in the cDAQ1Mod2/ai0 physical channels via cDAQ1Mod2/ai3:

  

  If you leave off of the entry "name" on the string to create VI, then the virtual channel names are the same as the names of physical channel, so it's the equivalent:

  

  And by the way, a right-click on the property and selecting "create > Constant ' context menu saves you from having to hardcode a number like 14712.

  Brad

• High level VI execution control... What don't get me?

  Hello all-

  I am writing an app that has controls on the front panel to access the calibration routines or collection of two subsets of channels on my data acquisition hardware (USB-6211)... called A Bank and Bank B.  The problem is that, once I called one of the subVIs, I lose the ability to call another user interface main... at least until the first call has finished its task and returns control to the main VI.

  For example, I'm collects data on Bank A and would independently to calibrate or collect on Bank B at the same time, TI later the keys on front lines until the first task is complete.

  According to me, I must be missing something quite basic here.  Maybe it has to do with selected delivery system or a bad design at a higher level?  Is the structure of the event that I use fouling things up?

  Because the 6211 don't let me read the analog-ins a subset of channels so that the other subset is busy, data acquisition, I try to read all 16 channels once per second (an average of values for about half a second), this data table can feed these subVIs for viewing or recording.  I need the DAQvoltagesAverage VI to run continuously in the background, update the table every second for use in the other routines.

  Am I way off here?

  Any help is greatly appreciated!  I have all downstream work, but were not able to understand this issue more high level.

  Using LabVIEW 2011 on MacOSX

  The structure of the event does not end the VI has not completed. In addition, you are locking thre façade in the configuration of the event. The main program Calera until the Subvi is in your implementation.

  There are a lot of way to independent lauch screws, for example using VI or "start the asynchronous call" server, for example. You can even use two independent loops while and structures for each event.

  (What is the purpose of the s 1. waiting seems useless here.)

• USB-6366

  I would like to taste several channels using different sampling frequencies high all the time and at the same time. Is this possible? If Yes, then how to combine measures of channels together in a chart?

  No, all the strings on 6366 share a sample clock.

  You could quick snack and then decimate a subset of channels in the software if it is feared too much data.

  Best regards

• Iteration in a structure of the event on the subset of elements of control

  I have an array of boxes that I want to live inputs switch indicators.  I have two tables which cell values feed indicators.  The checkboxes indicate which table is routed.

  My options are:

  1. Make a giant list of nodes of property with the switches (30 + switch, subset, property of update)
  2. make a loop that repeats against a ring (or cluster), where the iteratable enumerates objects to watch ring + loop + 1Passez pressing sur-sous-ensemble-update

  The second options seems so much more elegant than the first.

  I think that the references will need to be more channels.  I can make chains in a cluster and iterate on the cluster.  I don't know if I can do a mass of object references.

  Issues related to the:

  • How a list of references to the inidcators that a loop is ready to go and change the values?
  • Is there any value (for the rest of the system) for me to set a delay time delay in the events of the while loop + structure?  Is it CPU free for other things if he timed it delays for the control of the event?

  Artem.SPb wrote:

  What is the Ref out of problem in table?

  

  In the case of all Boolean controls as you, it is fine.  You will have an array of Boolean references.

  If you had some Boolean references, some numerical values, strings, and built a table of these references, the table will be an array of more generic references.  So when you use the properties on them, they will simply say "control".  You will be able to work on properties that all of these controls have in common (e.g. activate or visible), but you wanted to do something more specific, such as the display of a digital format, you will need to know that your ctrlref is to a digital, then casting that make reference to a class more specific to a digital for more specific class properties.

  If it is to group references in a cluster, each item in this group will always be most specific type.

• How to extract a D 1 waveform data in different channels to use for calculations on a page of data in real time

  Hi all

  I am a fairly new user to Labview and am trying to create a program that: watching the entries in different modules (9213, 9217) CompactDAQ sensors check errors and then uses data from some final calculations like averaging etc.  I've set up a small piece of code that includes the main functions that I am trying to accomplish.  Now I'm rather uncomfortable with getting set up and assigned channels, then pass these data in a while loop that continuously pulls the data from these sensors.

  I have the vi calculations complete and complement the inputs of channel UI, now, I'm working on the side of data manipulation and reading things.  The waveform D 1 who comes to read function is currently divided into components I want (given String Name and Y).  He then transmit this information out of the loop via a queue which transmits to the parallel loop below that will perform the verification errors and calculations of average.  There are some things that make it difficult. I showed the 2 sensors in my example, but in the actual program, there may be up to 400 entries.  The problem is that not all of these sensors will be used on all the tests that the software is used for.  To use the entries in the VI test for example: if I'm trying to the average of these 2 entries to create a common value, but then on a test, sensor 2 is not there, it must be recognized that fact and not use it in the service average.

  So to get down to it, I want to create something that can look through the D 1 waveform data groups, determine what these values are, then perform the functions necessary for these numbers once they are identified, then pass on the calculations of VI where it displays then usable for user information.  I think I'm having a problem with the finding in sorting than what I thought at makes me think that there must be an easier way.

  If someone has encountered this?  What is my explanation of what I'm trying to make sense?  Let me know and I can clarify.

  In terms of features, I don't see anything wrong. with respect to the effectiveness we must remember some general indications. These issues that I bring to the top will not affect your code now since your stack sizes are very small but can start to create the fragmentation of memory and slow down the software if your stack sizes are much larger and the software runs for a long period of time.

  1. try not to use the table to build. Whenever you use a table built labview creates a copy in memory. Try to initilized your berries and replace subsets.

  2. as much as you can try not index tables or unbundle cluster several times. try to perform as many tasks as possbile in one shot. (what was obvious in your second loop)

  In addition, he's looking good.

  I made a few changes to your code and attached to it. I wanted to give you a different on her opinion as it relates to being able to control entry and exit of programitically, if you had a look up table. I do not have the same changes to your second loop but I can guide you through what to do if you do not want to go in that direction. Yet once your original code is well done for someone who is new to labview, so don't feel you need to follow the new design of VI. Just try to remove the table construction and multiple indexing as a good habbit programming.

• How to return the subset of an array of basic condition bits

  Hello

  I have a question on how to get the subset of the table based on scraps of condition...

  For example, if I had a 4 x 4 array of 2D of DAQ system data.

  Table 1:

  1 2 3 4

  1 2 3 4

  1 2 3 4

  1 2 3 4

  and a 1 d table showing the conditions of each channel...

  Table 2:

  1

  0

  1

  0

  The function I want to do is to collect data only from the channel status bits are 1. In the above example, I want to only retrieve data from channels 0 and 2. Any idea? Thank you!

  Hi oly.

  Check this VI...

  Thank you and best regards,

  srikrishnaNF

• the ADC channel ID

  How can I read an adc channel id when I know I have four bytes.  The first byte of each block is the id of the channel and the 3 bytes are the measured value. Should I the subset of string? And how does it work?

  Thank you labviewviewer

  
  

• subset of binary string by string

  Hello

  a Visca cam command to convert a digital input to a string in hex display mode. Then I need the subset of the string and put a '0' in front of each single channel number.    for example, a digital input is 100, the string in hexadecimal display mode shows 0064. From there, I need to have 00000604. But the subset of string function divides 0064 00 and 64. How can I put a '0' in front of every single number? Is there any function to do this?

  Thanks for help

  Mark

  Hi Mark,

  Here is an example:

  

  The number 'split' can be replaced by Q & is too...

  Basically, divide your number in appetizers (aka demi-octets). This arithmetic is a little easier than to split strings to insert zeros before each tank.

• Motu 8 pre distorted his left channel

  Hello

  I bought a MacBook Pro 2014 2, 2 GHz i7, 16 G memory vivid and connected my Motu 8 pre via FireWire-> love at first sight. When you use it with Logic Pro 10.2.4 is immediately created questions about my left channel. The noise on the right channel is good, but the sound on the left channel is really distorted with a high cry inside.

  Even if I play music via iTunes for example which is good and I start logic the left speaker (always play music from iTunes) is distorted with this small high inside.

  I saw something posted by MillerU812 and tried all of the suggestions, without success.

  Any help would be much appreciated!

  Have you tried the reset.

  Unplug the computer. Hold the Volume button in 5

  seconds. You must first see the light flashing clock, then the first LED

  for analog input 1 or 2, then you will see a "D". Turn the Volume knob to the right until the display shows "OK". Device is reset.

• How the work of automatic channel selection?

  Hi all

  I was wondering how the AUTO function works on an Airport Extreme/TimeCapsule channel selector 2.4/5 GHZ?  He selects a channel only started upward or is constantly searching for the best channel and according to the needs of switching?

  

  Thank you.

  Hi solomani,.

  At startup.

• The Wi - Fi channel selection

  I use OS 10.11.6 in my condo where there are a number of Wi - Fi to the same ISP connections. When my computer wakes, it takes a long time to find my user name among all Wi - Fi channels detected by my machine. Can I block my Wi - Fi connection only to my username?

  The various networks are judges in their order of appearance, if you put you at the top of the list it will be the first to be tried.

  To change the order: go to System Preferences > network > advanced and then drag whatever you want at the top of the list.

• How to download a video I created my second YouTube channel?

  I recently made a video to my YouTube channel and I want to download on my second channel. But when I connect to my Google account it downloads only in the main channel. Is it possible that I can do this?

  Thank you all,

  Arda

  If you have only a single journal, you must use the YouTube uploader too.