delay in reading

Similar Questions

• Delay weird read shared variables

  Hello

  I'm working on a project were I am followed a few lines of production. I use an OPC server on the DSC module to connect to PLCs on the production line and I created variables related to my labview tags of the PLC project.

  On my project, I have a main VI were I show information on production lines and I can access several subVIs were I see more information on these lines. Then I a VI that runs in the background were I read about 50 shared the PLC variables and where I save data in a MySQL database, data entry of data on the database of the Citadel and the recording of alarms.

  The problem I have is that I noticed a delay read variables that read weight of containers from the production line the VI that runs in the background. It seems that all shared variables suffer no delay, only the variables weight start to make some delay when the values are on the rise. It also seems that when I run only one VI, without running the main VI, there is no any kind of delay. I read shared variables shared as variable nodes.

  Can someone help me understand what is happening and how can I fix this delay? The VI that runs in the background is time critical and a strange delay like that messes up my data.

  Hi Mateus23,

  The shared variable has various capabilites buffering, including integration with real-time FIFO functionality in LabVIEW Real-time.

  I guess that buffering settings are causing the unexpected behavior.

  Check out these resources:

  Buffer Network-Published static Variables (white paper)

  Properties shared Variables dialog box

  - Network Page

  - Page FIFO in real-time

• delay in reading the data when you are using multiple loops clocked on target RT

  Hello

  I have five loops clocked on a target of RT and I communicate to and from the host vi. All the loops of the value of the different priorities however when all running at the same time I found windows vi take up to 1 minute before reading the data. Four disabling loops to fix the problem. It is possible to start the app right after start windows vi?

  Kind regards

  Solved the problem by disabling variable autodeploy

  Thank you

• Delay on reading of slideshow - needed 5 minutes, but there is a limit of 1 minute.

  I try to get a collection of slide show to idle for 5 minutes and I'm disappointed to see that the upper limit is 60 seconds. I have two loop sequences of images in the slideshow to create the illusion of a video continuously loop (actually a sequence of images) which embarks on the entire screen after 5 minutes. It is a kiosk-type application that will be on ' always - on ' iPads in a store setting.

  The sequence of images was necessary because DPS do not loop video. A sequence of images has no function of late so I put two sequences in the loop of images in the slide show to get the delay function.

  I'm embarrassed my accession to the possibility of a 5 minute delay is a mistake and the need to find a solution.

  Ideas?

  See article "Nesting slideshows" in the Councils of DPS. It shows how to integrate a MSO in an other MSO.

• reading photoplethysmograph waveform with serial port on PC using Labview

  Hello world

  I'm gaining time real Photoplethysmography waveform of serial port using Labview.I have managed to acquire data from serial port by using the following features:

  -Baud rate: 38400

  -data bits: 8

  -stopbit: 1

   

  -No parity bit

  -Time delay before reading the serial port: 10 ms (according to what was written in the manual that every 10 ms there is a frame in serial port)

  After the reading string will be converted to byte array to be able to extract the bytes associated with waveform (1 & 2 bytes in a frame) even for SOP2 (6 & 7)

  (what is read in serial port is in decimal and must be converted to hexadecimal based on what made the software of prodeuct for some result.that in the waveform properties, I chose the hexadecimal representation)

  Then, as mentioned in the manual, I associate these two values to draw the waveform.

  Although I used the filter band digital waveform of pulse but not significant pass that was seen (cutofffrequeny:10 high low cut-off frequency: 0.5).

  I have attached my program and result in front of Panel and manual for the sensor. The result is still far from what is supposed to be. I was wondering if you could help me and let me know your opinion on the program and the protocol used. I have to get the result as soon as possible. Please let me know if you need more information.

  Kind regards

  
  

• FIFO DMA read high CPU usage

  Hi al, it's a long!

  I noticed a strange behaviour when I read from a FIFO DMA between FPGA and RT host on my crio (9014 controller and 9104 bottom of basket). The FPGA is writing data to the FIFO 2 points every millisecond and the loop of the RT is the reading of 500 data points each loop of the MS 250 CR period is controlled using the hold until the next ms multiple function.

  Wait until the next use means ms that during the first round, the wait will be not so I gave the FIFO DMA read method a timeout of 750ms to allow data points to accumulate on this first iteration.

  I then ran the VI and it read the data as planned and it was always 0 in the FIFO. Then using the system monitor, I noticed the CPU usage on the RIO and was surprised to see that it was 30% !

  After a lot of puzzle and many other attempts as to set the timeout to zero if delays fair read until here, I've decided are enough data points and then executes a little behind so that there is always a constant number (non-zero) of data points in the FIFO. Now, the VI runs and only use about 3% CPU.

  I thought that in the first case as I read exactly the number of points in the FIFO that I was tripping some kind of voting behavior in the playback feature which has been hogging the cpu.

  So I ran a business with a zero time-out, where I was reading with 0 points of data to the left in the FIFO as in the first case and waited to see if the delay of read but it never does and the CPU usage is normal.

  So what's happening? I'm puzzled!

  Thank you

  Steve.

  Hi Steve,.

  I think I can explain the use processor behavior that you are experiencing:

  Case 1: Loop with nonzero time-out

  -Your code starts with wait a multiple ms: This means that a 0-250 ms timeout occurs (on average 125 ms)

  -Then your code tries to read 500 data points in the DMA FIFO (if 500 points come in every 250 ms). All data cannot be presented yet.

  -If 500 points are not yet ready, polling occurs until they are. During the time of the poll, the CPU usage is high. Finally, the data is read.

  -The next iteration of the loop begins.

  -The code is now expected up to 250 ms after the last function call until the next ms Multiple. Roughly the same amount of data should be available by the end of this expectation as in the last iteration. Therefore, the question about the next FIFO DMA read should be roughly the same, and the CPU usage will remain high.

  Case 2: Loop with zero time-out

  -In your code, immediately after the first call to wait until the next multiple ms, you "synchronize" by reading all the remaining data from the FIFO.

  -In the next iteration of the loop, we can expect the call until the next ms Multiple wait the entire 250 m means that the data DMA FIFO (discount jitter) should be ready. If jitter is low enough, this will result in delays very little of the read DMA FIFO and a low CPU usage.

  I would recommend either using a timed loop and read the exact number of data points available (if your application can handle variable size data sets), or using a while loop as you are and make sure that the loop priorities are defined such that the CPU usage high does not affect critical functionality.

  Thank you for the very good question; I personally really like thinking through these issues! Please let me know if you have any questions that deserve further discussion and have a nice day!

  Kind regards

  Casey Weltzin

  Product Manager, LabVIEW Real-time

  National Instruments

• Adobe Audition 3.0 departure delayed when clicking on 'Play '.

  When I click on 'Play' or press the SPACEBAR to play an audio file, the green arrow room lights to the top immediately, but playback does not start away from playing audio for 1 or 2 seconds.  I use hearing to read prerecorded phone calls on the air, and it would be nice if I could tighten this delay in reading.  I use Windows 7 Pro 32-bit.  Any help would be greatly appreciated.

  Thank you!

  Ron

  After scouring the internet, I found the solution to this problem and thought I'd share it with all who would be interested.  The solution is clearly demonstrated in this YouTube video - how difficulty Lag in applications like Photoshop, Adobe Premiere, AfterFX, Vegas, etc (Windows) - YouTube

• Reading performance lag help

  I started editing my film and the first clips that I add to the timeline, delays in reading. Here are my specs are good enough? I have an external HD if it would help. I use to edit with iMovie on a computer laptop is much less powerful and never, he began trolling until I had reached the mark of 45-60 with tons of transitions and titles added already. He accuses only when I play it back from the timeline in the course of the program, and not in the source monitor. I looked through some other threads and noticed that someone asked if there was a red bar on the timeline. I have the red bar, it means something? Please help, thanks.
  
  

  Model name: iMac

  Model identifier: iMac10, 1

  Processor name: Intel Core 2 Duo

  Processor speed: 3, 06Ghz

  Number of processors: 1

  Total number of cores: 2

  L2 Cache: 3 MB

  Memory: 4 GB

  Bus speed: 1.07 GHz

  The source files are. MTS, did you ask?

  Project preset, I chose was DV-NTSC, Widescreen 48 kHz

  Well well... as I know... MTS will be HiDef and you have a draft standard Def, so you start with a delay

• Merger of iMac Drive need defrag?

  Hello

  I have a question for a long time I use windows and os x, and when I was on windows I analyze my hard and when I delete a large file I see Create a lot of distance between the files, so that was delay to read some files and use the defragmentation and which is really helping quick access my files and less pressure on my hard drive

  There's my basic question ' Mac think about it? How? " because there is no program for mac except IDefrag, which is not yet in the App Store

  Thanks for listening

  Defragmentation or erase free space accomplishes nothing. Apple moved space disk on the fly, so that all the big files are overwritten and the smallest are copied during the first. It may even be dangerous to do any of these procedures on an SSD.

• The time between VISA W/R

  I use VISA in communication series with PIC18F4550 (mcu, USB copy series), I found if I read immdiately afte writing, I can't get the right data all the time. It seems that the time should be at the same time between write and read funciton, and delay must be greater than 0.35 sec.

  Fact delay is necessary or I used to misuse Scripture VISA and playback function?

  Also look at the use of the chariot of termination and the setting of time-out to your advantage.

  1 turn on the tank of termination (depends on YOUR DEVICE PIC18F4550, read the instructions)

  2 set the timeout to something MUCH longer than necessary. (like 1000 ms)

  Write then followed the reading. No delay, bytes read no. to the port

  For the bytes of lonely bytes expected reading feature request.

  The Read function will wait for the full message that ends with the chariot of termination and will return with your message as soon as he gets the chariot of the termination. Or will he wait until the timeout before giving up on your device.

  You can then decide what to do with if time-out error message never comes.

  I have devices that take more than 3 seconds to answer because they have to go do something before they can meet. Some of my exhalations runs to as high as 10 sec. I have set the timeout on the fly, based on the order that I send.

• Different answer to 'Run' and 'step by step'?

  Hello!

  I'm working on a mini project to control a monochromater (model: Acton SP 2150i) and a photon-detecting.

  In my program, the first step is to get the initial condition of the monochromater, including current wavelength, cailleboti No. and the scanning speed. Please see step.bmp to summary the block diagram.

  What confuses me, is that when I "Single step" program, it comes out good value to me (see the step.bmp and stepfromt.bmp: current wavelength: 299.995nm, scan rate: 15 Nm / s, decking No.: #1), while I "run" the same program directly, it's weird responses (run.bmp shows: scan nm.) Speed: 0.016666/s, current nm wavelength: 0, decking No.: #1).

  Could someone give me some advice? I'm a newcomer to LabVIEW, and this problem exists for the weeks...

  Thank you!!

  TriStones,

  The fact that it works when you single step is an indicator of a synchronization problem.  You write the command to the instrument and then immeadiately check how much bytes is in the memory buffer of RRs.  Normally, I would suggest some delay between reading and writing VISA VISA to allow the complete response of the instrument to be received by the COM port.  In this case, there is a better way to fix your code.  Your instrument uses a termination character when it passes and you must configure your COM port accordingly.  Reading VISA will continue to read the buffer until either the termination character is received or a timeout occurs.  I suggest always configure the COM port in your code LV.  Do not rely on the computer or MAX settings.  A person can change something and interrupt your program.

  Extract attached should solve your problem.  Suggest you do some reading on NI-VISA and how to work the characters of endpoint.

  

• RECEPTION OF SERIES PROBLEM

  Hi... everybody... am using LABView 2009

  I did a VI.., because I need to receive the data by serialy and I answer back according to the data I received...

  here first am transmitting the data permanently (DOCK LIGHT - as a hyper terminal)... and am able to receive the data and also reply back through my VI...

  But if transmits me data only once in the DOCK LIGHT get no data...

  Please check my code and the answer me back as soon as possible, goes I am attaching my PROJECT.VI..., and Subvi.

  also the screenshot of DOCKLIGHT

  Concerning...,

  Maury

  How to run the VI?  You use the button run continuously?

  Run continuously is not expected to be used this way.  This is only to test the small screws that will later be used as subVIs and must be called repeatedly.

  Second, your serialcomm_subvi initializes and close the serial port whenever it is called.  You probably lose data during initialization or closing the port.

  Patches?  Wrap your code inside a while loop.  Add a stop button on your Panel before you stop the loop when finished.  Divide your serialcomm_subvi in three separate subVIs. The first is just the VISA set up series Port.vi.  Place outside the while loop and the name of resource VISA out of wire to the loop. The second part was writing, delay, and read functions. It goes inside the loop instead of your serialcomm_subvi.  The name of resource VISA to configure VI at the entrance of this sub - VI, rather than using local variables of the wire. After the loop put near the VISA.

  There may be other problems, but it will help you get started in the right direction.

  Lynn

• How to program the shift register to play only when a new user is detected user?

  Hello

  I'm currently developing a program of position control in labview. The program is quite simple, in which case the user will enter the distance on which he wants the table in the labview program and labview will send the signal to move a motor that will turn a ball screw to move a table horizontally to the targeted position. The criterion is that the profile of the engine depends on the distance to move, if a biphase (acceleration and deceleration) or three phase (acceleration, steady speed, deceleration) to reach the position of the target.

  The problem occurs when the user wants to enter a new entry second position) for the table, as the input by the user is the position that the table should be, but the necessary input to determine what profile the engine follows depends on the distance that the table moves to the target position. Therefore, I need a function to save the entry by the user temporarily and reminds that when a new user input is detected. Hereby, I would be able to use the difference of the input (input [n + 1] [n] input) and animal feed to determine what profile the engine follows and the entry by the user can be kept in the position he wants to the table to get (to compare with encoder).

  I thought to use for shift registers do, but I am not able to perform the deduction ([n + 1] - [n]) only when it detects a new entry. When I try to use registry to offset, it moves to the target location, and we only reached it will go to the original position. For example, when a user entry 90, this means that the table must be moved to the point 90. The shift register is initialized to 0, it will move to the point 90 (90-0 = 90), but arriving at 90, the shift register sends a signal of 90 (90-90 = 0) and the table back to its original position.

  Is it possible that I can delay the reading of the shift register only when a new entry is detected or there at - it another way for me to achieve what I want?

  I tried searching the forum site and neither discussion but could not find similar problems. Thank you for your help in advance.

  As I understand it, the use of shift registers with a structure of the event (to detect a user event when the user enters a new value) should solve the problem. Do not forget to post your request (or a version of it that isolates the issue) when you arrive at the lab, if we can get a clear visual of the issue you are facing.

• Manufacturing of Windows Media Player ".". WMA files"sound like a scratched CD

  Windows Media Player has recently started playing all back '. " WMA files"as they were damaged / scratched CD being played.  But when I take these same files to another program of reading, they play perfectly.

  When I start to read the file, I see the message "Change the media" and this may take a few seconds to more than a minute before the file actually starts to play.  Random playback when audio will jump sometimes, exactly in the same way he could play a scratched CD.  It repeats or taking a break before you continue reading.

  Then when it arrives near the end of the runway, HE STILL blew.

  After playing with it I finally understood that the jump at the end of each track has been the program of preparation for playback of the next track.  Because, when the next track begins to play there is no delay in reading.  But if I manually change the track then I get the message 'Change media' and delay important.  I think that the two are linked.

  As I said before, it started a few weeks ago and occurs only with Windows Media Player.  I in other audio programs, IE. Creative, don't do that.

  Furthermore, to the best of my knowledge nothing new has been added to WMP, IE. New Plugins, etc.

  Any ideas on what is the cause and how to fix.

  Thank you

  Hello

  The problem happens only when you play wma files?

  Disable audio enhancements and see if that fixes the problem.

  a. open peripheral Audio and sound themes by clicking the Start button, click Control Panel, hardware and sound, and then clicking sound.
  b. on the playback tab, click speakers and then click Properties.
  c. click the enhancements tab, and then check Disable all improvements.

  If you do not see the enhancements tab in the speakers Properties dialog box, these features are not available for your speakers, and this procedure is not applicable to the
  your computer.

  If disabling audio enhancements solves the audio problem you are having, this indicates usually that your audio driver needs to be updated. If disabling audio
  improvements do not solve the problem, contact your computer manufacturer for assistance.

  For your reference:
  http://Windows.Microsoft.com/en-us/Windows-Vista/how-do-I-stop-my-music-from-skipping-or-breaking-up-when-I-play-it

  Kind regards
  Afzal Taher - Microsoft technical support.
  Visit our Microsoft answers Feedback Forum and tell us what you think.

• ViewMail 8.0.3

  ENVIRONMENT:

  Unit 5.0.1

  Windows 7 Enterprise 32-bit

  Exchange 2007

  MS Outlook 2007

  We have recently improved our customer Viewmail on some workstations from 7.0.2 to 8.0.3 test and noticed a significant delay in reading. In addition, the progress bar is not synchronized with the reading as in previous versions of Viewmail. I found no documentation of VMO 8.0.3 did not support unity 5.0.1.  Any thoughts?

  They broke something that worked very well and because of bad tests, has not yet realized. This happens a .lot.

  Either downgrade you, or open a TAC case and fight uphill to see the problem found and fixed.