Synchronization of two sub-vis!

I am working under LV 7.0 and I have to acquire videos through FireWire. The cameras are included into LV via an ActiveX control. So far so good. Because I have to control 2 cameras I have to start the capturing simultaneously. I have written to sub-vis where I initialize the cameras and start the capturing. Now I am wondering how to synchronize these sub-vis because sometimes the files have different lengths, up to 5 frames or about one second. Is there a way to get this thing to work?
Thanks a lot in advance,
Henning

Hi Henning,
Please take a look at the example included with LV that can be found at
Help >>> Find Examples...
Optimizing Applications >>> Syncronizing Tasks >>> Rendezvous with SubVIs.vi
The help for this VI follows
This VI is a demonstration of using a rendevouz. It creates a rendezvous of size 3 and then calls three parallel subVIs using this rendevouz.
These subVIs use the rendezvous to synchronize the beginning of their loops. Each one displays integers to a graph. Finally, they all use the rendevouz to exit at the same time.
Please note that this will get sub-VI sync'd up at the begining of each cycle. I have to raise the concern that the actual interaction of the sub-VI's with their respective activeX service may end up se
quential if they all execute in the user interface thread.
The technique illustrated in my cited example should get all of your files sizes to match up.
I hope this helps,
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

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Running two sub vis in parallel

I need to run two sub vis of a main vi simultaneously in parallel.
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As i said
"If you have the demo vi as floating and the other vi as Default (not floating), the demo vi will allways stay on top"
If you still have problems, just post your vis, (without any unnecessary code), or ask something specific
Message Edited by Pnt on 04-21-2009 08:18 PM
Attachments:
Clipboard-2.jpg ‏44 KB

How do I run two sub-VIs in parallel and have the faster VI continue to execute while the slower one completes?

I have two sub-VI's - one that makes a laser distance measuring device turn on and return a distance, and another that moves a platform upon which a target is mounted that the laser reflects against. The laser VI takes well under 5 seconds to complet. The platform-moving VI, on the other hand, requires about 30 second. I would like to be able to have the laser on AS the platform moves. Of course, I can accomplish this by running the VIs seperately. However, I would like to control them from a master VI. Currently, the laser turns on as the platform begins to move but then turns off, since the master VI waits on the platform-moving VI to
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In order to synchronize the two VI's I would recommend using a global variable. By creating a global boolean, you can make reference to it in both programs, and control when your "laser" subVI terminates.
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Re: Calling two Sub VIs using Test sequence

Hii All,
I created main vi and one sub vi...i wanna to call sub vi from main vi using test sequence and controller is Bollean.
Means when the test sequence detects true condition it will run main vi and when test sequence detects False condition, it will run sub vi.. But sub vi is nit running...can some one tell me the solution...
With Regards
Puneet Kapoor
CLA 2014
CCVID 2014
Solved!
Go to Solution.
Attachments:
main.vi ‏18 KB
sub vi.vi ‏6 KB

thans for the suggestion...
i got the solution for it n the VIs is in the attachment.
Message Edited by puneet.kapoor on 12-12-2007 10:10 PM
CLA 2014
CCVID 2014

How to run two sub vi simultaneously??

i need to run two sub vi simultaneously in one main vi, becasue it is a must the two sub vi run exactly at the same time, but now i find that if i put they in one diagram ,in fact they are not exactly run at the same time. if you see in high light mode Just like the attached simple example code. any one can help me to handle this to run the two subvi exactly at the same time ? how to do it ? thanks so much.
Attachments:
how to run subvi simultaneously.vi ‏11 KB

You are correct, they will not run at exactly the same time. What is it you are actually trying to do? What platform are you developing on? What version of LabVIEW? What processor does your target system have? This information is vital in order for us to assist you. In a nutshell, unless you are running a real-time OS, then the OS you are running is not deterministic. When you say "at the same time", what are you actually referring to? As a note, when executing parrallel operations in LabVIEW, the execution order may or may not be the same with the highlight bubble on as it is when it is running without highlight execution. It is highly unlikely that you will be able to just run two sub-vis at the exact same nS. If you are using DAQ boards, you accomplish this through triggering. Please give a detailed description of what you are doing, and what you see the road blocks being.
Thanks
Paul <--Always Learning!!!
sense and simplicity.
Browse my sample VIs?

I try to open two sub vi front panel in third - main vi front panel.

I have two sub vi, and I`d like to see this two vi front panel in main vi front panel window. Does anybody can answer me , If it`s possible?

Click here for a recent related discussion.
Or have you thought about using a tab control? You can organize controls in pages and have those controls call sub-VIs with or without displaying the front panel of the sub-VI. See the Tab Control Properties.vi example that ships with LabVIEW.
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I need to do high sampling rate DAQ with varient data process and display.
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The other 2 loops in charge of the data processing and display will keep checking the version of the 2 function global.
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Hi Jim,
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hello, I want to use two indicators for the same variable in two different VIs running at the same time
should I use global variables?? I want to avoid because I have lot of variables and it would takes too much memory,I tried with this code but the value of the second indicator is not updated
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Attachments:
projet.zip ‏13 KB

CrisSTine01 wrote:
hello, I want to use two indicators for the same variable in two different VIs running at the same time
I'm a huge fan of User Events to send updates to GUIs from who knows where.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

How to configure time synchronization for two NTP servers

We have IOSXR 4.2.1 on routers CRS3 and ASR9K with all recomended SMUs; we need to configure the time synchronization for two NTP servers with the configuration below, but the routers became unstable; synchronize with one NTP servers for some time, then switch to other NTP server, and keep doing this. Anyone know why this behavior?
ntp
authentication-key 1 md5 encrypted 01070F074F0A05
authenticate
trusted-key 1
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server 10.192.32.33
source Loopback50
update-calendar
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Wed Jul 10 09:37:04.621 BRSPO
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RP/0/RP0/CPU0:Jul 4 21:30:21 : ntpd[256]: %IP-IP_NTP-5-SYNC_LOSS : Synchronization lost : 10.192.32.32 : Peer unreachable or clock selection failed
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RP/0/RP0/CPU0:Jul 4 22:25:07 : ntpd[256]: %IP-IP_NTP-5-HP_CONN_LOST : High priority NTP peer connection lost - Stratum 2->6.
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Hi Claudio, that ddts is pretty generic to be honest but yes it is filed to address sync issues in the XR NTP algo.
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You might get some joy if you set it to one server only and see if that helps?
regards
xander

I would like to know how i can create a bell graph with out using sub VIs, the data that i created consists in 500 readings with values of 0 to 100, i calculated the mean value and standard diviation. I hope some one can help me

I would like to know how i can create a bell graph with out using sub VIs, the data that i created consists in 500 readings with values of 0 to 100, i calculated the mean value and standard diviation. I hope some one can help me

Here's a quick example I threw together that generates a sort-of-bell-curve shaped data distribution, then performs the binning and plotting.
-Kevin P.
Message Edited by Kevin Price on 12-01-2006 02:42 PM
Attachments:
Binning example.vi ‏51 KB
Binning example.png ‏12 KB

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hi,
i have one SAP standard role. now i want to break this role into two sub roles. how shall do it.
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regards
ramesh
Edited by: Ramesh Sammiti on Jul 31, 2008 11:00 AM

Hi Ramesh,
When you say that you want to split the SAP Standard role into two roles:
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Save and Load Settings.vi ‏82 KB
Save and Load Binary File.vi ‏62 KB

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