Array of Clusters Counters / Shift registers

Hello All,
In my Array of Clusters, I'm having trouble controlling my MISS PACKET indicator. Each time a packet is missed , the MISS PACKET indicator increments by 1. My problems is, that the same number of miss packets is showing up in the MISS PACKET indicator in each array index if a packet is missed. Ex. So if index[0] has missed 30 packets, whenever index[1] misses a packet it will display 31 and not 1. I'm using a shift register to keep a count of the number of missed packets. I believe the shift register is the issue because the previous value is store whenever a packet is missed.
Any help would be appreciate !
Thanks
Attachments:
Final-Demo - 3.vi ‏52 KB

The first time i tried using a shift register I had the initalization done outside of the while loop and still got the same results
Attachments:
Final-Demo - 3.vi ‏47 KB

Similar Messages

Using a loop back node to build array okay instead of shift registers?

Attached is a sample of how I want to accomplish appending to multiple arrays and would like an opinion wether it is acceptable or not. I didn't want to use 12 shift registers wired from the 6 possible case structures mainly because of esthetic reasons. Each case will be called in turn during program execution only once. So case 0 builds it's array then later case 1 and so on. It seems to work but frankly manipulating arrays in LV confuses me a bit. I cannot test in the actual program since the hardware the complete program controls is not yet installed. Your input as to the wisdom of doing this or proposing a better solution (maybe one that actually works) is appreciated
Mike
Attachments:
sample2.vi ‏33 KB

You never have more than one element in each array since you initialize the shift register with every call of the VI.
Use "built array" instead of "insert into array", it's cleaner. However, since you only kep one elements, maybe you can jist place the scalar value inside a shift register. Make sure the default value is NaN so you know when it contains valid data.
All you probably need is an array of fixed size (12) and replace appropriate elements as need arises.
What you probably want is an action engine. See http://forums.ni.com/ni/board/message?board.id=170&view=by_date_ascending&message.id=240328#M240328
LabVIEW Champion . Do more with less code and in less time .

Programmatically create array from common cluster items inside array of clusters

I have seen many questions and responses on dealing with arrays of clusters, but none that discuss quite what I am looking for. I am trying to programmatically create an array from common cluster items inside array of clusters. I have a working solution but looking for a cleaner approach. I have an array of clusters representing channels of data. Each cluster contains a mixture of control data types, i.e.. names, types, range, values, units, etc. The entire cluster is a typedef made up of other typedefs such as the type, range and units and native controls like numeric and boolean. One array is a “block” or module. One cluster is a channel of data. I wrote a small vi to extract all the data with the same units and “pipe” them into another array so that I can process all the data from all the channels of the same units together. It consists of a loop to iterate through the array, in which there is an unbundle by name and a case structure with a case for each unit. Within a specific case, there is a build array for that unit and all the other non-relevant shift registers pass through. As you can see from the attached snapshots, the effort to add an additional unit grows as each non-relevant case must be wired through. It is important to note that there is no default case. My question: Is there a cleaner, more efficient and elegant way to do this?
Thanks in advance!
Solved!
Go to Solution.
Attachments:
NI_Chan units to array_1.png ‏35 KB
NI_Chan units to array_2.png ‏50 KB

nathand wrote:
Your comments made me curious, so I put together a quick test. Maybe there's an error in the code (below as a snippet, and attached as a VI) or maybe it's been fixed in LabVIEW 2013, but I'm consistently getting faster times from the IPE (2-3 ms versus 5-6ms for unbundle/index). See if you get the same results. For fun I flipped the order of the test and got the same results (this is why the snippet and the VI execute the tests in opposite order).
This seems like a poster child for using the IPES! We can look at the index array + replace subset and recognize that it is in place, but the compiler is not so clever (yet!). The bundle/unbundle is a well-known "magic pattern" so it should be roughly equivalent to the IPES, with a tiny penalty due to overhead.
Replace only the array operation with an IPES and leave the bundle/unbundle alone and I wager the times will be roughly the same as using the nested IPES. Maybe even a slight lean toward the magic pattern now if I recall correctly.
If you instantly recognize all combinations which the compiler will optimize and not optimize, or you want to exhaustively benchmark all of your code then pick and choose between the two to avoid the slight overhead. Otherwise I think the IPES looks better, at best works MUCH better, and at worst works ever-so-slightly worse. And as a not-so-gentle reminder to all: if you really care about performance at this level of detail: TURN OFF DEBUGGING!

For adding about 70 shift registers to my VI , will it affect the performance of the project or it depends on my PC ??

I have 70 shift registers to accumulate date from 70 channels to plot it every channel individually , will these shift registers affect the performance of the project or it depends on my PC ??

Osama90 wrote:
I have 70 shift registers to accumulate date from 70 channels to plot it every channel individually , will these shift registers affect the performance of the project or it depends on my PC ??
It will certainly affect your performance and ability to handle/change your code. Change it to an array of plots, either as a 2D array (if using the same sampling rate), or an array of clusters with the channels (1D array?) as data. From a machine perspective 70 SRs should work, but not from a person perspective.
/Y
LabVIEW 8.2 - 2014
"Only dead fish swim downstream" - "My life for Kudos!" - "Dumb people repeat old mistakes - smart ones create new ones."
G# - Free award winning reference based OOP for LV

Multiple shift registers in For loop

I'm using multiple shift registers to find the number of different string in a string array. However, the shift register got refreshed every time it finds a different string and returns back to 0. How can I have the register remember its previous value after it encounters a new string value?
Solved!
Go to Solution.
Attachments:
count.vi ‏19 KB

You should think about making your code scalable. At the moment, you need to re-architect the VI from scratch whenever the sensor names or their number changes. If you suddenly have 1000 sensor names, the code would be unmamangeable because the sheer number of cases and shift registers!
Attached is an simple alternative. As you can see, the code remains the same, even if the number of sensors or their names changes in the future. See if it makes sense. (You can easily modify it to also count unrecognized names, for example).
Modify as needed.
Some other possible bugs in your VI:
You should initialize the shift register with zero, not one. Right now the results are one too high.
Case "B" is actually "B." and the count is only accidentally correct because it is also the default case and there are no other sensor names (e.g. F) in the input array.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
CountMOD.png ‏19 KB
countMOD.vi ‏19 KB

Any way to sample segment length longer than loop iterations w/o shift registers?

Hi all,
My loop iterates approx every 0.06s and now i've been asked to add to the program a function which will sample the most recent 3s of data and return the max/min value for two of the signals. I can think of a programmatically clumsy way to do this with shift registers- take the max/min for each iteration, save-repeat-compare until you have enough iterations to fill 3s of time. But I can't help but think there has to be a cleaner(better?) way to do this.
Any help?
Thanks
Solved!
Go to Solution.

Hi there,
Try looking into a circular buffer.
http://zone.ni.com/devzone/cda/tut/p/id/7188
Once you've determined how often you're putting entries into the buffer, you'll know exactly how big of an array to grab and do the Min/Max on.
Another option is to use a circular array.
http://decibel.ni.com/content/docs/DOC-3414
I would set this up to function a little like a Functional Global or an Action Engine. The subVI would then be used in your DAQ loop to "stack" new data. And then called in another loop or part of your code to be read every three seconds.
Patrick Allen

Keyboard "tab" control in Array of Clusters

I'm trying to polish some of my LabVIEW user interfaces so that my users can work faster in them and so that they follow more "Windows UI Standards" (or whatever).
I have an array of clusters. The cluster has 3 numerics.
When a user "focusses" on the first numeric within a cluster and hits the tab key, it moves the focus to the second numeric. Hit tab again, and it jumps to the 3rd numeric. Hit the tab key a 3rd time and it jumps back to the first numeric in the cluster. What I want to happen is for the focus to move to the first numeric in the next element of the array.
I've started to play around with the "Key Down" event case that has a conditional looking for "TAB" and then checks the "FindCtrlWithKeyFocus" with the last numeric. My probes within this event show that the "TAB" key detection is working, but the "FindCtrlWithKeyFocus" never has a TRUE output from the "CtrlFound?" output of the Invoke Node.
Even if I did know if tab was pressed in the last element, I'm not real sure how to move focus to the first numeric within the next cluster element of the array.
A numeric array behaves in the correct way. I could get the program working the way I want with a 2d array of numerics. However, each numeric has different data entry parameters and there is also a lost of "self documentation". I would like to find a solution because this has come up with other, more complex, array of clusters that would not be solveable with a 2d array of a base type.
Seems overly complicated to me.
Bonus Question: The default value of my numerics is 0. When my user clicks a numeric the cursor is on either side of the 0 and the user has to delete the 0 prior to their data input. When a numeric is entered via the Tab key, the whole field is selected. When the whole field is selected, whatever the user inputs will replace the original "0" that was in the field. Anyway to have the whole field selected when the user uses the mouse?
Sorry for the wall-of-text post (and the preposition hell). Thanks for your input.
Solved!
Go to Solution.

Well I've gone and gotten the tabbing behavior you're looking for.
-the key is to set "skip when tabbing" on the controls inside the clusters to true, and leave it false for the array elements. Now when keyfocus is on one of the cluster controls and Tab is pressed, LV will put the keyfocus on the next visible array element.
-then use a "key down?" filtering event to check and see if any of those controls have keyfocus when Tab is pressed. If so, and it's not the last control in the cluster, discard the keypress and programmatically advance keyfocus to the next item.
-Finally if the Tab press was not discarded, use a normal "key down" UI event to check if one of the array elements now has keyfocus and if so, set KF to the first control in its array.
So in short, this setup turns off tabbing along a row so that every tab will move to the next row. Then it filters out Tab if it's not yet at the end of the row. Finally, it automatically puts the cursor in the first column when the row has advanced.
One significant drawback is that it only tabs between visible array elements. You can probably make it auto scroll.
I'll leave it as an exercise for the reader to handle the shift+Tab (reverse tabbing) key presses.
To me, this runs up against three holes in LV UI programming:
1) Array Element events should be available. The Array:Key Down event only handles key presses when the array has keyfocus, not when things inside it do. Any kind of key filtering has to be done at the VI level (!!!).
The data source for these events should include the element index (eg what cell was clicked on?)
2) There aren't effective ways in VI server to deal with individual array elements. I recognize that some of it is the basis that array elements have the same properties, but there are display and selection properties that do differ between cells. I ought to be able to specify that a particular cell index has keyfocus. Arrays, why can't you be more like Tables?
3)Tab order should be flat, not hierarchical.
edit: in case the snippet messes things up, file is attached.
-Barrett
CLD
Attachments:
Tab through cluster array elements.vi ‏28 KB

Array Of Clusters Not Initializing or Possible Race Conditions

Hi all,
I've been working on a fairly complex project for work, and I haven't worked with Labview before. Unfortunately nobody in my office really has experience with it so I'm on my own. I've mostly got the project working, and it might be a little cumbersome, but if it works that's fine.
Essentially it's a temperature control device and I made it so it's expandable, thus the clusters and arrays everywhere.
My question is this. I've got an array of clusters indicating the status of all the plates in the system. When I start up the VI for the first time they do not initialize. They just stay grey, but when I stop it and start it once, it will work every time. I think this is kind of strange behavior. I've heard of race conditions and while I've tried to make sure t hat's not happening, it might be without me noticing.
I've tried putting an initialize array block in the first call while loop and that doesn't do anything, and if I remove the initializer from the shift register in the top while loop that stops them being initalized altogether.
I guess I was hoping someone might have an idea what's causing it, or could possible give my code the once over. The main bulk of it is in the very top of the code, but there are a lot of smaller events taking care of GUI type stuff.
I've included all source code. It might be a little much but I didn't want to start pulling it apart if I don't know what's happening.
Thanks in advance.
Chris.
Solved!
Go to Solution.
Attachments:
Error During Cycle Controls.zip ‏3107 KB
Stop Cycle Controls.zip ‏2115 KB
Stop Cycle Controls.zip ‏4975 KB

Chris Johnson wrote:
So just to confirm, I can have one event structure with say 10 events happening? In this case could an event happen simultaneously with another? I thought I read something about each event having it's own event structure and while loop to make sure this works out.
Each event case must complete before it can handle the next event, but many events will complete so quickly that this is not an issue (such as your "pause chart" button). In general you should have only one event loop. If you expect an event to take a long time to process, use a queue to hand that task off to another dedicated-purpose loop, so that the event structure can go back to waiting. This is one example of the producer-consumer structure often mentioned on this forum: the producer is the loop containing the event structure, and it queues (produces) items to process. A separate loop dequeues (consumes) those items and handles them appropriately.
As GerdW mentioned, you have race conditions all over the place. You'll never know whether the Plate Info Cluster Array is properly updated because it's being written and read simultaneously in so many places. I'm assuming that is also where you're seeing the issue that inspired the post, and, in fact, one of those race conditions could explain what you're seeing.
Chris Johnson wrote:
Also, again, to confirm what I think I already know. When the event completes it outputs whatever data you output from the structure and then you can place it in a shift register. Where does this go until the next event takes place?
I don't understand what you're asking. Where does what go until the next event? If by this you mean the data in the shift register - it stays in the shift register, accessible at the corresponding terminal on the left side of the loop.

Array of clusters does not updates properly

Hello...
I builded a VI to split a series of 10000 values in many segments, each one overlapped by 50 %. The product of all the values of each segment is calculated and by means of visual inspection and Led selection (green means that the segment will be used, red means that the segment will not be used), I can select which segment will be used for the final sum. For example: if I have 20 segments, but only segments 4, 8, 15 are green, only the products of the segments 4, 8 and 15 will be summed to generate the final result. The final result should be refreshed if the Lenght of the Segment is changed or if any Led is switched to green or red, but the update does not occur properly. Sometimes all the segments are showed properly but if I change one Led or the Lenght of Segment control, the given result is wrong. When the Lenght of Segments control is changed, all the Leds need to be adjusted to green state.
I don't know where is the problem in my code, but I think that is something related to the cluster constant that is wired to the first Unbundle by name, since that this constant was created from the cluster before it was inserted into array, and not from the array. If I create the constant from the array, the code returns an error.
To avoid race conditions I used flat sequence.
Thanks in advance for attention and help.
Dan07
Message Edited by dan07 on 07-26-2008 08:31 AM
Attachments:
Array of clusters.vi ‏43 KB

I spotted one problemous area:
Where you have an uninitialized shift register, so for every event the value of the last iteration is used.
What's the meaning of this piece of code?
I think you devide the length of the array by half the length of the segment?
Ton
Message Edited by TonP on 07-26-2008 05:34 PM
Free Code Capture Tool! Version 2.1.3 with comments, web-upload, back-save and snippets!
Nederlandse LabVIEW user groep www.lvug.nl
My LabVIEW Ideas
LabVIEW, programming like it should be!
Attachments:
Array of clusters_BD.png ‏2 KB
Array of clusters_BD2.png ‏1 KB

Calculate maximum value of subarray while creating it using a case structure and shift registers

I have two 1D arrays that contain cyclical information (kind of like a sine wave). One that contains information on position in degrees and another that contains torque. I would like to calculate the maximum torque value each time the position is within a certain range (e.g. from 30-80 degrees). The ranges are repeated - that's why it is cyclical. I use the "in range" function, a case structure and shift registers to build a new array with values that fall within the range I specify - this was the easy part (see VI attached). I'm struggling with a way to calculate a maximum value for each subarray formed when values are "in range". Your help is much appreciated.
Solved!
Go to Solution.
Attachments:
Simple Calculate between anatomical position range.vi ‏16 KB

It's not really noise - it's more inconsistency. So a position output can run: 20, 30, 40, 50, 60 etc. OR, it could run: 21, 24, 32, 41, 44, 51, 59 etc. But, it is always cyclical.
Attached you will find a .csv file with the data arrays - I'm using POS (ANAT) degrees column (column D if you open in excel). There you also see torque in ft-lbs along with some other information.
Attachments:
025C.csv ‏224 KB

Capture Last ten Shots (Shift Registers)?

Situation: -
I am continuously acquiring data on 4 channels of the DAQ card using conditional triggering. Each loop captures 2000 samples, which are stored in 2-D waveform arrays containing each scan of each channel. The data is continually updated on a waveform graph for the user to monitor. After a period of "test time" or when you press a button, the loop will end and the last loop of waveform data gets passed to the analysis VI where all the calcs are performed (I only perform calcs/analysis on static data once test time has completed).
Problem: -
I now want to average the last 5-10 points prior to the while loop ending (as the injection needle will jump around slightly shot to shot). I can enable indexing on the while loop and then select the points I require afterwards (i.e. the last 5-10 or whatever), but this takes up a hell of alot of memory and the processor starts caching to disk too often. Can you imagine just how many points are stored in memory (2000 samples/channel, 4 channels per scan, sampling at 80KHz, for 10mins).
There is no need to store all these points. Each time the loop iterates, the buffer is cleared so the program runs quickly and smoothly. All I need to do is store the last 5-10 waveform array's and pass these on to the next VI, not the whole XXXXXX amount of arrays/point.
I may try and use a sequence, so that the first sequence uses disable indexing and ends after the "Test time" has elapsed. This then continues into the next sequence and proceeds to capture a further 5-10 shots with indexing enabled, before passing to analysis VI. This still doesn't really capture the last 5-10 iterations, it captures the next 5-10 iterations, but it would do.
Ideally, I want the while loop to execute with indexing disabled, and at a certain point in time (comparing the "Test Time" with the "sample rate"), the while loop changes to 'indexing enabled' which will build up an array of waveform data until the loop ends (about 5-10 iterations later).
Any Ideas. If you've got time on your hands..........

You can use a shift register. This will just maintain the last "n" amounts of data sets. I've attached a really simple example to illustrate this.
This may work for you needs however there is an issue that the shift registers are in essence being used the whole time so you will have more memory interaction than you may want ... which depending on your performance requirements may not be desirable.
If that is the case then it may be best to slightly modifiy the approach you're using. Indexing continually instead of in the main loop. Set up a condition/case upon which within the main loop you initiate a sub loop that then starts logging the data you require for averaging.
Hope this helps,
Kamran
Attachments:
ShiftRegister.vi ‏36 KB

Clear shift registers between runs

Hi,
Noob question of the day! I am building an array and would like to clear shift registers between runs. I have attached a VI. It runs a while loop every second and adds that iteration number to an array. I then display the length of the array. I would like it such that each time I press run, the program starts with a "blank slate." Any standard way of clearing everything. I would love to do something like:
clc
clear
if it were matlab...
Solved!
Go to Solution.
Attachments:
shift register count.vi ‏8 KB

What do you know, I guess the problem is that I am left handed. Sometime I even confuse up and down.
Yes I meant the right-click the left shift register.
LabVIEW Champion . Do more with less code and in less time .

Static Shift registers

My understanding of shift registers is that if you don't initiaze them
then they will hold the value from the last instance, hence be static.
I've created a subvi and placed multiple copies in a case statement,
all it does is check to see if the value has changed, yet when it runs
the second time it starts out at zero when it should be whatever
number went through the sub the last time.
Am I missing something here?
Bundle to byte array contains single to byte array sub vi
Ron
Attachments:
Bundle to Byte array w change.vi ‏29 KB
Single to Byte array w change.vi ‏10 KB

You should always consider initializing shift registers. Keep in mind that if you just opened a VI that contains uninitialized shift registers, it won't remember the data from the last time it was run (because it has been unloaded from memory since then), so it's more likely the values in that shift register are garbage. That could be even more dangerous, since how LabVIEW interprets that data could cause very strange and erratic behavior in your application.
Here's my solution that works for Functional Globals and general shift registers: Consider initializing them the first time the VI is called inside the While Loop, as demonstrated below:
The First Call VI outputs a true the first time that instance of it is called, and false every other time. For Functional Globals you could alternatively have a dedicated Initialize case to perform this function. The advantage of the technique listed above is that you are guaranteed initialization on the first call, regardless of whether the client programmer remembers to call an initialization case.
Message Edited by Jarrod S. on 04-11-200612:33 PM
Message Edited by Jarrod S. on 04-11-2006 12:33 PM
Jarrod S.
National Instruments
Attachments:
Pic1.jpg ‏7 KB
Pic2.jpg ‏14 KB

Replacing shift registers with queues or notifiers?

Hello World,
I'm using labView 7.1 with my first application, which is essentially a spectrum analyser and comparison to limits. now due to the parameters of the sampling 12000 samples/sec with 4096 point I have quite large chunks of data involved in rolling averages of 1 minute and rolling buffers that are an hour long. I'm pretty new to labview but I'm finding pretty easy to pick up except when it comes to optimisation and performance (I've been used to the microsoft approach until now) due to the fact that the instrument I'm building has to run in psuedo "real time".
I've been looking at replacing the shift registers with either queues or notifiers but I'm unsure if these techniques would result in improvements or not.
I'll attach a jpg of my main loop, I've only got the one but it is separated into three separate tasks but they are all governed by the data flow, DAQ then PROCESSING then REPORTING.
I've been told that by separating the loops and making them run in parallel LV will be able to compile it more efficeintly, but I'm unsure how to do that .
Cheers
Andrew
90% of all experts aggree that 1 out of 10 experts are wrong
Attachments:
Step 14 -Post Course Mk4d.jpg ‏376 KB

Fat Controller wrote:
Hello World,
I'm using labView 7.1 with my first application, which is essentially a spectrum analyser and comparison to limits. now due to the parameters of the sampling 12000 samples/sec with 4096 point I have quite large chunks of data involved in rolling averages of 1 minute and rolling buffers that are an hour long. I'm pretty new to labview but I'm finding pretty easy to pick up except when it comes to optimisation and performance (I've been used to the microsoft approach until now) due to the fact that the instrument I'm building has to run in psuedo "real time".
I've been looking at replacing the shift registers with either queues or notifiers but I'm unsure if these techniques would result in improvements or not.
I'll attach a jpg of my main loop, I've only got the one but it is separated into three separate tasks but they are all governed by the data flow, DAQ then PROCESSING then REPORTING.
I've been told that by separating the loops and making them run in parallel LV will be able to compile it more efficeintly, but I'm unsure how to do that .
Cheers
Andrew
Don't convert shift registers into queues or other things for performance reasons! LabVIEW has a lot of internal optimization logic when compiling your code which works best on shift registers. On a queue you will always copy the entire data of a message in or out even if you only need one byte of it.
Try to look at your architecture. You do want to do as much as possible in place. Try to completely avoid Append Array or Append String inside loops if possible. They are costly operations as they have to reallocate memory each time and often copy the entire data from the first array into the resized array. Better is to once preallocate an array of the necessary size, keep it in your shift register all the time and then use Replace Array Subset, Index Array and Array Subset nodes only on this. You will also have to maintian some index shich tells you up to where you have currently filled that array and that one is usualy best put into a shift register as well.
Rolf Kalbermatter
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

How can I modify the cluster values in an array of clusters?

Hi all - I can't believe that I am having trouble with this but for some reason I am completely wrapped around the axel with it. I have an array of clusters, they are all strings but with different names. I am using key configuration VIs to setup a readable text file for the user. I also want the user to be able to load up the array of clusters with the values that are in the text file. So I am reading the keys and trying to populate the array of clusters to show what is in the text file and then run the test using those values. However I am not able to get the clusters populated correctly. Does any one have an example of what I am trying to do? Basically I am trying to populate an existing array of clusters with new values. That is what it comes down to. Thanks in advance for any help.

Go to jki and dowload VIPM (VI Package Maager). From there you ca install OpenG. Lot's of useful stuff.
Also if you cosider XML to be readable you can use flatten to/from XML.
=====================
LabVIEW 2012

Array of Clusters Counters / Shift registers

Similar Messages

Maybe you are looking for