Flat sequence bug

Good morning.
I was working on a report generation vi for my project, and it has grown way too stacked. Loop within case, within sequence etc.
To keep a large VI tidy I was using the cleanup feature.
After another cleanup my 2 stacked sequences and 1 while loop became "bugged".
I tried to restart both labview and, later, the PC. Bug did not disappear.
Is there any way to fix the bug? I tried to replace structures with alternatives from right click menu. After few conversions the problem is not seen, but shortly appears.
Any way maybe with HEX editor?
Flat sequence thinks it has a stacked sequence wall on the right side. Mouse can't be seen on screenshots though.
Attachments:
PIC2.jpg ‏139 KB
PIC3.jpg ‏165 KB
PIC4.jpg ‏142 KB

I tried to move your structures around, but this happened:
Clearly this happens because of the massiveness of your VI. Luckily I was able to see the whole thing on my 1789 inch TV
A usefull tip: Don't create a blockdiagram that is bigger than your monitor, preferable not over todays 22 inch standards. Now-a-days I'm working on a rather big project and to be able to have the block diagram of my main VI within my screensize of 22 inches, I had to create more than 100 sub-VI's. But it's way easier to have a clear view over the whole program, than a 16k+ pixcel block diagram that can only be viewable on my 1789 inch .
I also believe many of the flat sequence structures can be removed. You should use the error wire for dataflow control and use sub-VI's if you got repeating code. Use logical icons for you're sub-VI's. Here is an example, which I prefer to use:
Red icons to easily see my Sub-VI's from standard LabVIEW icons, and also some text that I can refer to with comments so that other people understand what the sub-VI's do. This way my main VI does not have a block diagram larger than my monitor.
Regards,
Even
Certified LabVIEW Associate Developer
Automated Test Developer
Topro AS
Norway

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KDI Digital Instrumentation.com
e-mail: [email protected]
Tel: +49 (0)441 9490852

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Hello there -
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P.S. - I have attached a copy of the VI that I am working on, but unfortunately, it most likely will not run on your computer....the VI will not run unless it is connected to a triggered spectrometer and CCD camera....but I have attached it anyways incase anyone who can help might want to take a look.
Attachments:
RTSpider.vi ‏376 KB

can we divide the program into 2 parts and use background process for acquisition and front end process for analysis?
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Attachments:
poll_loop2.GIF ‏13 KB

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How to break a flat sequence structure ...??

How to break a flat sequence structure into two flat sequences structures......i am a student learning labview....help me..

To accomplish what you want you need to basically write some really ugly code. This is a side effect of using the flat sequence structure in the first place. This is exactly why they are not recommended.
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Error when using class wire in flat sequence

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I would not say it is "expected" behavior but quite possibly it is very correct behavior (Read as "almost certainly").
"Wrap-your-head-in-duct-tape" and read message 12 of this thread carefully. Dynamic terminals that are on the connector pane determine which DD vi is actually called at run time. Unless those terminals are on the root diagram there is a chance they could be conditionally read or even in dead code (imagine the sequence frame was replaced by a case structure since all structures are treated as "structures") this breaks "inplaceness" and if not resolved, by placeing the terminals on the root diagram, LabVIEW would need to determine at run time wether or not a buffer allocation was required. Thats not really possible.
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Nested Sequences Bug is finally fixed?

I just noticed that Apple seems to have patched a significant bug in FCP with the last update.
According to my own tests, Nested Sequences now update automatically and consistently without having to be re-added or refreshed in the timeline.
Nesting is when a sequence is placed into another sequence. Complex projects may involve several layers deep of nesting, but FCP users have been wise to avoid this useful technique because it just didn't work right.
For example, if I were to build a neat animated logo sequence, then nest it inside a standard footage sequence, the animation would play through and be scalable like any other footage. This allows for a simpler "master track" timeline based workflow where everything is not placed into the same huge sequence.
In the past, the sequence containing a nested sequence would not get updated if one made a change to the nested sequence after placing it. So if I were to change the animated logo sequence mentioned above, the change would not show up in the footage sequence that hosts it. I believe this has finally been fixed in 5.04
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Has anybody else noticed this fix, or am I just dreaming here? I really am excited about this.

It was fixed as I described until about a month ago, when I noticed the problem was back. This could have coincided with an OSX update. It also might have been the update to QuickTime or Pro Applications Support as well. I don't know. But the problem is back and I noticed it "the hard way" during a dub. Sorry for not amending my post when I noticed this.
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Continuous loop for flat sequence

Hi, I currently using LabVIEW 8.2 and still learning about LabVIEW. I’m doing a project on a FMS model using USB 6501 to run the program and I’m required to run the program continuously. I was given a program from a previous student and I’m supposed to modify the current program. The purpose of the program is to gather stock from the warehouse and place it in a different slot.
I have a sample of the program and layout of the model where the lift is to move to the left and back to the right. I’m currently stuck as I can’t figure out how to run the flat sequence continuously.
Firstly, it would just run once and stop at the right even when I’m using while loop.
Secondly, when pressing the stop button it wouldn’t stop the program midway, it would continue to run until the frame ends. Is there a way to stop the frame when an error occurs?
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Attachments:
LIFT LOOP.vi ‏288 KB

You definetly have to switch to a reliable architecture!
I think that your application must have several security features to prevent damage of hardware or even humans. So you must not use a program which just moves the lift from startpoint to endpoint without any chance to break the movement!
That being said, i see two approaches:
a) Statemachine
b) Producer/Consumer
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Producer/Consumer can possibly react a little faster if it is event based. The backdraft is that you need a rather good knowledge of LV in order to implement this properly.
Another thing for applications like this are latencies created by the OS. Maybe it is necessary (not only recommended) to switch to a RT system or even FPGA in order to keep proper reaction times.....
Maybe it is a good idea to talk about this application with an NI Alliance Member .
hope this helps,
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

How to execute a frame of a flat sequence structure for a specified amount of time?

Hello,
I have a timed loop measuring a resistance value every 2 seconds. I would like to have this timed loop execute for a specified amount of time (e.g. 5 minutes). The timed loop itself is placed within a flat sequence structure so I am concerned that the measurement will be taken once and the next frame will begin to execute, without waiting 2 seconds for a successive reading (and not looping for, say, 5 minutes).
In other words, is it possible to have a frame of a flat sequence structure execute for a specified amount of time before moving onto the next frame?
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JFK_Aero
Solved!
Go to Solution.

All code in one sequence frame must complete before the next frame can execute. So as long as your timed loop is setup correctly, the next frame cannot run until your 5 minutes is up (N = 5 minutes/2 seconds/measurement = 150 measurements).
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Timed loop inside a flat sequence not terminating

Inside a while loop there is an event structure. Inside that there is a flat sequence. On one of the frames there is a timed loop that quits after so many iterations. The timed loop finishes but the flat sequence doesn't execute the next sequence. What am I not doing right?

First, you have too many local variables. This could be leading to race conditions.
I think you have a couple problems in the use of event structures. It is a bad idea to put any long running code inside an event case. It will prevent the Event Structure from handling any other events in the mean time. You have several timed loops running that in that one sequence frame.
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You have laid out the code very neatly, but you have used a lot of odd things in there. (Number to boolean array, to cluster, to unbundle the cluster to individual indicators.) Why not just go from Boolean array to and index array function. No need for the intermediate cluster conversion. Why not set up the indicators as an indicator array and just write to them directly.
The code is so much intertwined between when queues are created, filled, emptied, destroyed, events happen... And this is all multiplied by at least 4 times for each camera. And there are 4 major event structures going on. This is a very ambitious project for an inexperience LabVIEW user. You need to step back, get one thing working right, and design so that you can scale the architecture upward. Many of the structures you have essentially duplicated and belong in subVI's.

Where can i find flat sequence in a function palette

Hello
Where shall i find flat sequence in the function palette of LabVIEW 6.1 version.
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Jayaprakash
Attachments:
Flat sequence.doc ‏79 KB

Hi
The flat sequence is just available in LV version 7.0 and newer.
In LV 6.1 you have to use the stacked sequence-structure.
Thomas
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Don't be afraid to rate a good answer...

LED in flat sequence event

Hello,
I have 2 flat sequence event with 1 LED in each event. How do I turn on the LED when the event start and OFF when the event complete before it move to next event.
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Thanks,
Solved!
Go to Solution.
Attachments:
LED.vi ‏7 KB

Those are not events in the sequence. Those are individual frames. Events in LabVIEW are something completely different. Based on your question it seems you are not completely understanding dataflow. A function/VI will execute when all data on the wires connected to it is present. Dataflow can be used to enforce execution order, but sequence frames can also be used.
In your first frame if you wire a True constant to the Boolean you cannot control when the Boolean is updated since there is no data dependenct between the numeric calculations and the writing of the LED. Thus, if you want to turn on the LED before the first frame then you need to add a frame before the first one where you set the LED, and the same thing at the end.

Measure the time in a specific frame of a flat sequence

Hi I have a labVIEW program with a flat sequence and I would like to stick in a small SubVI which measures how long it stays within an individual frame to confirm the delay I have used. Does anyone have any code or any tips on what I could add which sets a timer going when I enter the frame and spits out the answer to a numeric indicator when it goes to the next frame.
Any help would be appreciated

srikrishnaNF wrote:
hi mr_nice,
Use time elapsed vi...
Thanks and regards,
srikrishnaNF
Please add where you find this vi.
Check out this video here. It might be useful for you when he talks about the flat sequence structure and how to get elapsed time from it. It starts at about 7 minutes into the movie. He's using Tick Count.
Also here you can find useful information
Regards,
Even
Certified LabVIEW Associate Developer
Automated Test Developer
Topro AS
Norway

CS4.2 - Nested Sequence bug!...

I seem to have stumbled upon a bug in Premiere CS4.2 (it is probably present in all versions of CS4)
I am trying to build some professional looking transitions, but to accomplish them I am having to nest sequences (though it would be nicer if I could add effects to transitions themselves to avoid nesting [cough] Adobe[cough], or be able to use transparent video clips as adjustment layers)
Anyhow, 2 things: One, On my main timeline I have the Push Transition between two clips set to go from Top to Bottom (doesn't have an issue when going side to side)
Second, I have a photoshop file being used elsewhere on the timeline with a scale effect to use as a transition (going from 600% to 100% with no other motion).
(Both are having the same issue - below)
I have the Photoshop file and the Push transition on my main sequence which is then nested into another sequence so I could add a blur effect to the transitions, and then I have that sequence nested into a third sequence that is set to square pixels so I can output a quicktime to Youtube (the original 2 Sequences have a 1.21 widescreen aspect in case I want to go to dvd)
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But everything is fine in the other two sequences! So I'm not sure what's causing this issue other than a bug in Premiere.
Just FYI, I did also try turning all the effects off (except the Push transition), but that didn't change anything.
Thanks all for any help, (or a new CS4 update - wink, wink)
I hope this is clear enough.
Aza

There's a point that I don't understand, shouldn't a un-optimul workflow (using clips that require a lot of rendering power from the cpu and disk access) cause things to slow down or frames to drop?
Why would such a situation cause every frame to be played with cpu and disk access to spare but cause frames to be played in the wrong order? I've never encountered anything like this before.
There are no stuttering or gaps between frames, just frames being played as if the clips were in the wrong order.
Example:
Sequence A contains Sequence B then C
Sequence B: Clip 1, 2, 3, 4
Sequence C: Clip 5, 6, 7, 8
Playing from Sequence A: Clip 1, 3, 2, 4, 5, 6, 7, 8
Playing from Sequence B: Clip 1, 2, 3, 4
Playing from Sequence C: Clip 5, 6, 7, 8
Playing from Sequence A (again): Clip 1, 2, 3, 4, 5, 6, 7, 8
*Wait a while, do something else*
Playing from Sequence A: Clip 1, 3, 3, 3, 5, 6, 8, 7
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No clips or frames were ever dropped.

Flat sequence bug

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