Fastest way to read and write to/from muliple DAQ channels

I'm developing an application in which multiple DAQ channels will be monitored, for example, displacement, load, strain, temperature and so on. My question is what is the fastest and most efficent way to check the value of these inputs, compare them to user inputs and then decide whether or not to write a different voltage to an output. I'm using LV 7.1 on Win 2000.

I guess my first question would be are all these channels going to be on one card? Are you going to just make single measurements (are you interested in instantaneous values vs. "waveforms")? Doing a "Sample channels" for instance will make a single measurement of several channels (on the same board) and present you with an array of the resulting data, one element per channel. How fast do you need to sample, are all of the signals going to be on the same board? The latest NI-Daq allows configuring tasks that mix channel types (T'couples, straight voltage measurements, etc.) which makes configuring the DAQ easier.
If you can give us a little more information regarding what you are trying to accomplish it will help.
P.M.
Putnam
Certified LabVIEW Developer
Senior Test Engineer
Currently using LV 6.1-LabVIEW 2012, RT8.5
LabVIEW Champion

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Fast way to read and write console

hi guys
what's the fastest way to read and write from console?
For writing I'm using (I think thats the fastest way)
System.out.println(foo)and I have to read the following - all numbers are ints (that means m + n + 1 lines):
1 * "<n> <m>"
n * "<a> <b> <c>"
m * "<a> <b>"Actual I'm reading (the second line for example) with
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String[] items = br.readLine().split("[^\\-\\.0-9]+");
Target mainTarget = new Target(Integer.parseInt(items[0]), Integer.parseInt(items[1]), Integer.parseInt(items[2]));
for (int i = 1; i < m; i++) {
items = br.readLine().split("[^\\-\\.0-9]+");
mainTarget.addTarget(Integer.parseInt(items[0]), Integer.parseInt(items[1]), Integer.parseInt(items[2]));
} But that isn't really fast...
have you any idea?
grz faetzminator

faetzminator wrote:
right, I have 1 + 1 + 1 =3 up to 10^6-1 + 10^6-1 + 1 =2*10^6-1 input lines with max 4999997 integers (and I have to store 2999999 of them)
ok, if that is the fastest way... (maybe the reading of the input file is so slow; I run eg "java Foo < input > output")All those br.readLine calls where you never check if the return is null are dangerous.
I really don't understand what you are doing. You mentioned System.in at first and now reading from files.
I also am pretty sure that you are in fact running out of memory.

What is the fastest way to record and write image data?

Hello,
I am new to labview and am using the IMAQ software package to record and write data from a CCD camera to the hard drive. The end goal is a program that records and saves as much data as possible as quickly as possible, for experiments lasting on the scale of days. I have been experimenting with the snap, grab, and sequence methods of recording. To save the image data I was told by NI customer support that TDMS streaming would be the fastest method. I have also been experimenting with the TDMS VIs, however I have found the IMAQ Write File 2 VI to be faster in practice. Am I doing something wrong with the TDMS file structure? Is there a more efficient way to convert IMAQ image data to a dataform that can be written as TDMS? I am posting two of my programs to provide a clearer example of what I am trying to do. The first takes a snap of the image and appends it to a TDMS file. The second is the fastest I have found so far and uses Grab to record the images and the IMAQ Write File VI to save them.
Thanks
Attachments:
Camera Capture (Snap) and stream TDMS.vi ‏24 KB
Camera Capture (Grab) and write image.vi ‏24 KB

Hi
For me it is no surprise that the second VI is faster then the first one, the reason is you can not compare this two VI with each other.
In the first VI you work with TDMS files, in the second with png files. That would be much faster, because TDMS files need a lot of diskspace.
Second point, why do you open, write and close for eacht iteration of the for loop a TDMS file in your first VI? That need really a lot of resources, so it coudn´t be fats as well.
Save your converted pictures in one array, an after the acquisition you can save it in one TDMS file. When you need for each picture a TDMS file you have to know that this need some time to do this.
So now for the architecture of your first VI, please look to the LL Sequence.vifrom the examples (C:\Program Files\National Instruments\LabVIEW 8.6\examples\IMAQ\IMAQ Low Level.llb\LL Sequence.vi), there you can see how an acquisition of a number of images have been to do.
When you like it really fast, you make a producer/consumer architecture (see examples in LabVIEW for that).
So in the first whileloop you acquire the images, write into a queue and in the second, parallel whileloop you read the queue and save the images. (see attachment)
Hope that helps
Kind regards
Beat
NI Germany
Attachments:
ProducerConsumerData.vi ‏10 KB
ProducerConsumerData_LV8.5.vi ‏12 KB

How many ways to read and write a local variable in a called VI?

Ciao!
I'm producing my first TestStand sequence. It is called "FirstAttempt" and it is made by a single step which calls a VI. One of the first dilemmas i encountered realizing this sequence is how to read and write a local variable (created going in Variables -> Locals ('FirstAttempt') -> <right click to insert local>) in the called VI.
The first way (the only one i tried) is to create a control and an indicator on the VI front panel, connect them to their respective terminals in the connector pane and then specify (going in Step Settings -> Module) that these connectors (shown in the Parameter Name column) are linked to the local variable (selected in the Value column).
The second way (not tried) consists in using TestStand API: create a Sequence Context reference on the VI front panel, link it to a property node in the block diagram, select the property "Locals" and extract from this the local variable name and value which, i think, can be readable and writable.
So...
Are the shown ways correct?
Are there other ways?
Knowing that a "local" variable can be considered "global" within the whole sequence, is there the possibility to simply create a reference to the local variable and use the reference in the called VI block diagram in order to save space in the connector pane (if using method 1) or in the block diagram (if using method 2)?
Thanks!
Message Edited by aRCo on 09-17-2009 05:09 AM

Hi,
Before TestStand 3 you would use the second way you quoted as its the only way.
But now you would use the first way you quoted. You may still what to pass the SequenceContext if you were going to use the TestStand API. For TestStand 3.x and above you would use this way as the first chose. (Personnelly, I would not pass the SequenceContext into a VI if I know it was never going to be used in that VI.)
Not sure I understand your final comment, maybe you are liking it to passing the reference of a control to a subVI so that the control can be updated from within the subVI.
If this is the case and you had a situation where you had a step that was running in parallel with the rest of the steps in the sequence either as a separate thread or execution and were dependent on the contents of the local variable changing from that parallel running step, then you would have to use the API SetVal method to change the local.
Hope this is clear.
Regards
Ray Farmer
Regards
Ray Farmer

How to read and write data from json file from windows phone7 app

Hi
I am developing wp7 app for the use of students my questions are
How can i write a code to read and write the json/text file for the wp7.
I am using windows 7 OS, VS 2010 Edition.
This is my code below:
xaml:
<Grid>
                    <TextBlock Height="45" HorizontalAlignment="Left" Margin="7,18,0,550" Name="textBlock1" Text="Full
Name: " />
                    <TextBox Width="350" Height="70" HorizontalAlignment="Left" Margin="108,1,0,0" Name="txtName"
Text="Enter your full name" VerticalAlignment="Top" />
                    <TextBlock Height="45" HorizontalAlignment="Left" Margin="6,75,0,0" Name="textBlock2" Text="Contact
No: " VerticalAlignment="Top" />
                    <TextBox Width="350" Height="70" HorizontalAlignment="Left" Margin="108,61,0,480" Name="txtContact"
Text="Enter your contact number" MaxLength="10" />
                    <Button Content="Register" Height="72" HorizontalAlignment="Left" Margin="10,330,0,0" Name="btnRegister"
VerticalAlignment="Top" Width="190" Click="btnRegister_Click" />
                </Grid>
xaml.cs:
private void btnRegister_Click(object sender, RoutedEventArgs e)
            string name, contact;
            name = txtName.Text;
            contact = txtContact.Text;
            try
                if (name != "" && contact != "")
                    string msg = name + " " + contact;
                    MessageBox.Show(msg);
                    Student stud = new Student
                        Name= name,
                        Contact = contact,
                    string jsonString = JsonConvert.SerializeObject(stud);
                    MessageBox.Show(jsonString);
                else
                    MessageBox.Show("Input Proper Information", MessageBoxButton.OK);
            catch (Exception ex)
                MessageBox.Show(ex.Message);
I have download NewtonSoft.json version 5.0.8.
So, I am able to convert input data into json format, but how can I able to write and read this data from a json/text file.
How can I do?
Thank you in adv and please, reply soon.

We don't have many samples left for Windows Phone 7 + Azure, the closest one to what you want to do is probably:
Using Local Storage with OData on Windows Phone To Reduce Network Bandwidth
this sample uses the local database feature: 'LINQ to SQL', available to Windows Phone 7.1 and 8.0 Silverlight applications, instead of simple file storage but even if you choose to stick with simple file storage I believe you should be able to adapt the
networking related portions of the sample to your particular application.
Eric Fleck, Windows Store and Windows Phone Developer Support. If you would like to provide feedback or suggestions for future improvements to the Windows Phone SDK please go to http://wpdev.uservoice.com/ where you can post your suggestions and/or cast
your votes for existing suggestions.

Read and write info from/to file available at client side.

Hi,
I have some table name in one CSV file at client side.
once you get list of tables name from input CSV file at client side.
Need to run one query to know total rows and size of table in MB , this i need to repeat for all tables which i got from input file.
finally write 'table name | total rows | size of table in MB' whole info in another CSV file at client side. this output CSV file name will contain timestamp.
Please guide me in detail how to read and write file avail at client side.
I am using sql developer at client side.
version : oracle11g
Thanks in advance.

This is a simple SQL question and this forum is for SQLDEveloper, however, this is a question for our SQL*Plus support which can help with this.
clear SCREEN
set FEEDBACK off
set head off
--Gather stats to populate rownums and avg length of rows.
--These are not exact sizes (obviously) but you get the idea.
begin
dbms_stats.gather_schema_stats ('<YOUR_SCHEMA');
end;
select TABLE_NAME||','||NUM_ROWS||','||ROUND((NUM_ROWS*AVG_ROW_LEN)/(1024*1024)) CSV
from USER_TABLES
where num_rows is not null order by num_rows desc;

Read and write data from content repository .

Hi All,
We are using content repository to store some document and images on web center server .
So we have created/setup a content repository on web center .
Please proivde me some documnet /wiki page to get some idea how can i read and write date in
content repository .
You are most welocme to provide some idea /suggestion .
Thanks,
Arun.

Have you already configured webcenter spaces so it can use content server?
Have you installed the content server seperatly from webcenter or as a part of the webcenter installation?
Check if you have the webcenter spaces component installed in content server because without i don't think it will work...
If you already have configured UCM to work with spaces it's quiet easy.
From your groupspace, open the settings page of your groupspace. Go to the services tab. In the left hand side you can enable the documents services. WHen you have done that, you are able to add the document services taskflows to your pages. Just go to a page in your pagegroup and edit it. Open the resource catalog and you will find some extra taskflows you can add.
If you haven't configured UCM and webcenter to work together, here some steps that will help you:
* Integrating UCM with Spaces
     * They both need to use the same LDAP store.
     * Since there is no LDAP server available, we choose for embedded WLS LDAP.
     * Integrating the ucm into apache
          * Stop UCM
          * In /oracle/product/wls10320/WebCenter/ucm/config/config.cfg, check the SocketHostAddressSecurityFilter to contain 127.0.0.1
          * Add the SocketHostAddressSecurityFilter to /oracle/product/wls10320/WebCenter/ucm/admin/bin/intradoc.cfg
          * Add to /oracle/product/wls10320/WebTier/instances/instance1/config/OHS/ohs1/httpd.conf
               include /oracle/product/wls10320/WebCenter/ucm/data/users/apache22/apache.conf
          * Change the mod_wl_ohs.conf file to
               <IfModule weblogic_module>
                     WebLogicHost localhost
                     WebLogicPort 7001
                     Debug ON
                     WLLogFile /tmp/weblogic.log
               </IfModule>
               <Location /webcenter>
                  SetHandler weblogic-handler
                  WebLogicCluster localhost:8888
               </Location>
               <Location /webcenterhelp>
                  SetHandler weblogic-handler
                  WebLogicCluster localhost:8888
               </Location>
               <Location /owc_discussions>
                  SetHandler weblogic-handler
                  WebLogicCluster localhost:8890
               </Location>
               <Location /em>
                  SetHandler weblogic-handler
               </Location>
               <Location /console>
                  SetHandler weblogic-handler
               </Location>
               <Location /consolehelp>
                  SetHandler weblogic-handler
               </Location>
          * Restart UCM & WebTier
          * Test URL: http://yourServer:7777/idc
     * Configure the Identity Store for UCM & WebCenter
          * Set the password for the embedded ldap in WLS
               Console => Domain Name => Security tab => Embedded LDAP tab => reset credentials
          * Restart AdminServer
          * Stop UCM
          * Add the following to /oracle/product/wls10320/WebCenter/ucm/config/jps-config.xml
                  <serviceInstance name="idstore.oid" provider="idstore.ldap.provider">
                      <property name="subscriber.name" value="ou=myrealm,dc=webcenter_domain"/>
                      <property name="idstore.type" value="WLS_OVD"/>
                      <property name="security.principal.key" value="ldap.credential"/>
                      <property name="security.principal.alias" value="JPS"/>
                          <property name="ldap.url" value="ldap://yourServer:7001"/>
                      <extendedProperty>
                          <name>user.search.bases</name>
                          <values><value>ou=people,ou=myrealm,dc=webcenter_domain</value></values>
                      </extendedProperty>
                      <extendedProperty>
                          <name>group.search.bases</name>
                          <values><value>ou=groups,ou=myrealm,dc=webcenter_domain</value></values>
                      </extendedProperty>
                      <property name="username.attr" value="uid"/>
                      <property name="user.login.attr" value="uid"/>
                      <property name="groupname.attr" value="cn"/>
                  </serviceInstance>
          * In the same file, change the serviceInstanceRef ref="idstore.ldap" to "idstore.oid"
          * Go to /oracle/product/wls10320/WebCenter/ucm/custom/FustionLibraries/tools
          * ./run_credtool.sh
               Alias: default
               Key: default
               User Name: cn=Admin
               Password: weblogic123
               JPS Config: default
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          * Check Provider:
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               * Login : sysadmin/idc
               * Administration -> Providers
               * jpsuser should be good
               * When a ldapuser exist, disable it!!
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          * Change the file /products/WebCenter11gR1/WebCenter/ucm/config/config.cfg
              SearchIndexerEngineName=DATABASE.METADATA to SearchIndexerEngineName=DATABASE.FULLTEXT
          * Restart UCM server
          * Run the /products/WebCenter11gR1/WebCenter/ucm/database/oracle/admin/batchsnippet.sql in the wcbepsc_ocserver schema
          * Restart UCM server
          * Open the /products/WebCenter11gR1/WebCenter/ucm/bin/RepositoryManager (sysadmin/idc)
          * Recreate the indexes
     * Registering UCM with WebCenter
          * Go to http://yourServer:7777/em
          * Login with weblogic/weblogicPassword
          * Go to WebCenter - WebCenter Spaces - webcenter (WLS_Spaces)
          * From the top menu, select Settings - Service Configuration
          * Select Content Repository
          * Add
               Connection Name: ucm_connection
               Repository Type: Oracle Content Server
               Active Connection: checked
               Administrator User Name: sysadmin
               Root Folder: /WebCenterSpaces
               Application Name: Spaces
               CIS Socket Type: Socket
               Server Host: localhost
               Server Port: 4444
               Authentication Method: Identity Propagation
          * Restart WLS_Spaces
     * Test the connection by creating a new group space and upload a document to the document page of this group spaceHope this helps.

Read and write data from / to cube in CUSTOM_LOGIC BADI

Here are the details:
BPC displays a set of details - with 5 rows and 5 columns. There are 50 additional rows for the 5 columns which are blank to start with.
User changes a cell. BPC 10 only sends that cell which is changed by the user in CUSTOM_LOGIC and WRITE_BACK BADIs.
I need to get other 5 X 5 cells (other than 1 cell, which is changed and being passed in the BADIs) details to determine all the details and calculate the additional 50 rows. After calculating these values, i need to update the cube so that the BPC report refreshes with the data i have updated.
Whats the best way? What are the funtion modules involved in reading / writing? Are there any best practices to read / write data from cube.
Appreciate your help.

Hi Ravan,
Look at my sample write back badi here: http://scn.sap.com/message/14290977#14290977
At the end of the code I have values updated in ct_data. The contents of ct_data will be automatically written to the cube (you don't need to have special code to write data).
B.R. Vadim

Read and write Values from Configuration File in BizTalk

There is a requirement where Biz talk orchestration read the value dynamically from Config Store.After some process updating the value in config store.
I though to use SQL Server and create one table with single column.Biztalk will call the Storeproc to get the value and similary for update system will call another SP.
Instead of using SQL Server DB is there option to implement this requirement like app.config,BTSsvcxxexe.config ,SSO Config store etc.
If multi-users access the value from Config store and try to update ,how to handle lock mechanism.

Hi BizQ,
Refrain from using BTSConfig file or any custom config file if you have a requirement to update the data. Modifying a
configuration file at runtime can cause some nasty, unexpected behavior inside your application if it's not managed properly.
I would suggest you to use Custom DB or SSO Database in this case.
Both have their Pros and Cons.
SSO Database:
You get out of the box encryption
It is a central store which will service all BizTalk servers within your group
SSO implements a caching mechanism internally for the data
Custom DB:
By storing the configuration in the database you don’t have to worry about consistency of data across servers like you would with a config file.
Cache needs to be implemented by program to avoid delays in reading from physical file.
In your case I recommend to go with SSO DB as in terms of storing custom configuration data in SSO for End Point/Application
specific information and credentials and potentially configuration information which you also need to write and update at runtime from your code or via an administrator.
You can use Richard Seroter's tool to store values as "Config Store" in SSO database and then write a .net helper
utility to retrieve it using SSOConfigStore class. It has method GetConfigInfo and you need to pass application name with other parameters. It returns ConfigurationPropertyBag from where you can read property name and values.
http://seroter.wordpress.com/2007/09/21/biztalk-sso-configuration-data-storage-tool/
http://blogs.msdn.com/b/teekamg/archive/2009/08/19/sso-configuration-application-mmc-snap-in.aspx.
Rachit
Please mark as answer or vote as helpful if my reply does

How to read and write data from Excel to TestStand without using LabVIEW VIs

Hi,
How can I read in columns of data from Excel into a TestStand array and write columns of data to Excel from TestStand without using LabVIEW VIs?
I don't think the Property Loader custom step type in TestStand will work because the data I would like to read in from Excel is in a column that is thousands of rows long and the data has to be in the proper format to use the Property Loader to load in an array from Excel.
Thanks for your help.

That example does not use LabVIEW and it does about 40% of what you need to do by calling Excel through ActiveX. If you don't know how to use Excel through ActiveX then you'll need to brush up on that.
http://www.microsoft.com/en-us/download/details.aspx?id=16250
http://support.microsoft.com/kb/141759
http://support.microsoft.com/kb/302084
CTA, CLA, MTFBWY

Best way for read and write?

Hello
I'm working on project with labview .
with this program i connecting PC to the MCU through sreial RTU modbus .
in this program there are some data need to be read and some data need to write .
what i need is most of my time reading polet exuted exept when some of control element (like edit box) has changed by user .
when ever some thing changed by user write polet excuted .
now what is the best way to do this ?
Best Regards.
Solved!
Go to Solution.

mori64 wrote:
What uou said sound complicated to me .
i'm trying to undrestand your solution .
i'll be happy if you upload sample program .
State Machine
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Read and write data from virtual port (bluetooth adaptor)

Hi,
I want to read and wirte data to the bluetooth adaptor by java. I connected my bluetooth adapter to COM3.(virtual port). Anybody help me with this.I need very urgent.
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Deepa_05 wrote:
Hi,
I didn't get jar fileAnd?

Haskell: fastest way to read and print a file? & hGetBuf example?

I was playing around with simple IO in Haskell just for the sake of learning and decided to implement a very basic version of "cat" for a rough speed comparison. Being a Haskell noob, I tried various combinations of readFile and hGetContents from System.IO before I realized that they read a single Char at a time, which explained why there were slower than even Python and Perl. I found the hGetBuf function but I couldn't figure out how to get my data back from the Ptr. Eventually I ended up with this:
import System( getArgs )
import qualified Data.ByteString as B
main = getArgs >>= (B.readFile.head) >>= B.putStr
time cat /var/log/pacman.log | wc
297783 1945570 32536814
real 0m0.624s
user 0m0.620s
sys 0m0.017s
time ./test /var/log/pacman.log | wc
297783 1945570 32536814
real 0m0.671s
user 0m0.640s
sys 0m0.040s
where "test" is the program above compiled with "ghc --make test.hs -o test -O".
So, my questions:
1) Is there any way to shave off the last few milliseconds to make it as fast as cat for that operation?
2) Can someone give a clear example of how to use hGetBuf, specifically how to "marshall" a Ptr into a String or ByteString?
I've tried to find examples but the very few that I've found haven't been that helpful.
Slightly off-topic yet tangential questions:
*) Does anyone else find it irksome that you have to dig through Haskell's abstraction to deal with the underlying system? I'm only just beginning to learn it but I've already come across a few things which feel like square blocks hammered into round holes.

@CBM80
Thanks for the link. I've bookmarked it for now.
@brisbin33
I've been coding a bit in Haskell lately and it feels like I'm getting comfortable with it, including monads (e.g. state transformers, system IO). I think I'm over the first big conceptual stumbling block and it's starting to feel much more intuitive. Nevertheless I still generally agree with that statement, although now I would have worded it differently.
It feels like they've pulled a sheet over the underlying system. You can still see the basic shape of it and where different bits protrude, but you're supposed to pretend that it's all nice and smooth. If you want to do anything serious with it, you have to cut a hole through the sheet (i.e. use the foreign function interface and another language which can get to it) to gain full access.
When I wrote that I think I actually had Ints and Integers in mind. The difference between them is only how the underlying system represents them. From a purely abstract|functional perspective, there should be no distinction between them. I understand that the language is ultimately bound by the hardware and I actually appreciate that the distinction can enable the programmer to optimize his code. It just annoys me that there is a layer of abstraction that prevents me from exerting more control over the types. For example, it would be nice to be able to declare my own "PositiveInt" type and have it represented by an unsigned int in the underlying system. I can "see" from within Haskell how "Int" is represented, but I can't create a similar representation (without resorting to the FFI, afaik). There has been talk about this before and how to make all types user-definable. Some tutorial even give the dummy declaration of Int as "data Int = ...|-3|-2|-1|0|1|2|...". Obviously you would need some sort of meta-language to handle it though (which seems to be in the works).
For the record, I think the FFI is great and I see great potential in it and can't wait to start using it.
At some point I solved some of the problems on Project Euler (and got sidetracked with Perl and Python solutions). My quest to learn Haskell has also been periodic and so far I haven't gone back to PE but I intend to. Btw, I found it insightful to compare my solutions to the solutions posted in the wiki. They're full of little epiphanies.
*edit*
I realize that many apparent limitations are likely due to my own ignorance. I'm reading through the pages posted by CBM80 and already see some ways to get around the abstraction.
Last edited by Xyne (2010-05-06 19:03:17)

Read and write blob from client to server

Hello,
is it possible to read a word/pdf-document from a client-machine into a blob-column of the database (different computer) and vice versa write the stored word/pdf-document from the database to the client machine.
As far as I know, dbms_lob.readfromfile only works on the directories of the server. How is it possible to accomplish this from the clientside (Forms, C++, .Net WPF)? Is there a http call for such things?
Thanks in advance for help.
Anna

I think JDBC, C/C++ call interface, Perl DBI, etc. can all do BLOB read/write without having to reside in the same database server.
-Haijun

Read and write binary from txt file

Well
i need to know how to convert strings to binary data
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I know that i have to use OutputStream and ImputStream classes, but i don know how it works...
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Fastest way to read and write to/from muliple DAQ channels

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