Newbie Labview Question: Array of clusters

1: i am a student
2: this is not homework or a graded project
3: I'm a pretty capable programmer, but that's in text-based languages. ;-)
I have a sensor feed which contains 4 channels. I need to leave all 4 channels active, but I want to select one of them to graph at any given time. The data from the NI driver for the hardware comes as a 1x4 array of 2-element clusters.
Normally, I'd just index to the desired element in the 1x4 array, and feed that cluster to the appropriate graphing tool, but I'm missing something. I swiped a display element from the NI driver example VI's, but any time I insert blocks between the data feed and the graph I get "bad connection" errors.
I've been googling and book-looking for several days now, to no avail, I'd appreciate any help in this question.
in the image at ( http://dl.dropbox.com/u/4286123/LabviewHelp.jpg ), what block do i need to insert into the highlighted wire to be able to select and graph only one of the 4 data channels, controlled by an integer source?
Many thanks.
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Use the Index Array funtion found in the Array palette. Wire in the index number of the waveform you wish to display.
- tbob
Inventor of the WORM Global

Similar Messages

Labview How to specify 1d array of clusters as data types for variant to data

Hi, I'm new to labview. Can anyone tell me how to specify 1d array of clusters as data types for variant to data?

First of all, you should be sure that there is such a data type within the variant; otherwise, you will run into errors.
I recommend you to create the cluster and create a type definition from it. Then drop an array shell from the array palette and drop the cluster type into that array.
Connect that constant to the data type input of the Variant To Data function.
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

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.
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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.
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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.

Show/Hide certain items in an array of clusters

I am trying to figure out how to programmatically show/hide certain items in a cluster (specifically an array of clusters). I tried a couple of things but nothing worked for me. On a similar note, I would like to be able to programmatically hide certain columns in a table. I can’t figure it out and the postings on the LabVIEW forums here were either not terribly helpful for my situation or maybe I just didn’t understand them. I have attached a vi where I tried to hide items within the array of clusters. Maybe someone could point out why it didn’t work and hopefully they could provide a solution or direction for me to follow. Thanks in advance…
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Attachments:
make column hidden.vi ‏15 KB

Creating a property node directly to the cluster element is far easier. pcardinale essentially shows this.
As for the question regarding the table columns, there is no direct way to hide the table columns, viz-a-viz Excel. The closest you can get is to set the column width to zero, as shown in attached example.
Attachments:
hide table columns.vi ‏13 KB

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!
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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!

Reference to Array of Clusters with an array element

Hi,
I have an array of clusters CONTROL (calling it as "top level cluster array") with one of the cluster elements being a cluster array (please see attached).
I plan to pass "Reference" of this top level cluster to different VIs (like add element VI, insert element VI, delete element VI etc) and access (add/modify delete) the elements in this array.
In my code, how do I typecast the Array Element (cluster) to the inner cluster (as shown in the figure) ?
I am using LV RT on PXI.
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You cannot use references in the same way that you use pointers around in C. LabVIEW does not manage memory in the same way that C does. This is actually a good thing, though C programmers find it "cumbersome" or "restrictive". I have also programmed in C, and frankly I prefer LabVIEW's memory management any day of the week.
You had not initially mentioned that this was going to be done in multiple places at (potentially) the same time. Given that, my recommendation is to look into using Action Engines. They provide a means of basically providing a one-location acccess for your data. By using a single VI to access/modify your data you preclude the generation of race conditions. You may also want to join this with the concept of using variants to provide a means to quickly find your data rather than looping to find the element you're interested in. This technique has been around for a while and it has been discussed before. There are examples floating around. Will need to check to find one.
As for your question regarding using the reference method which you tried to employ in your initial approach, that's simply not going to gain you anything. You will still be creating buffers when you try to access the cluster elements. But you already have this information in the array inside the outer for loop, so you're just creating unnecessary extra programming for yourself.

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

Using Event Structures with Array of Clusters

Using LabVIEW 8.5
Hi all,
I'm trying to convert an existing application to one that can be used
through a touch screen. I updated the UI and added an event structure
to listen for mouse ups on controls that require a HMI keyboard or
numpad to show up. Although I've been programming for a while, I'm new
to LabVIEW and am struggling with a problem:
Is there any way to have an event case listen to an event within
arrays? I've seen a few examples on the forums, but they all start with
breaking up the arrays into individual variables. Using the variables,
they build arrays. This seems pretty tedious, and I'm pretty sure I
can't apply it to one of my arrays. Essentially, I just want to know
which cluster in which array the user has clicked on, so I can open the
HMI keyboard or numpad and send the text to that cluster. In my watered down app (Array of Clusters.vi), I've put 3 arrays of clusters and a few stand-alone controls to give you guys an idea of what I'm taking about.
BTW, I'm using the HMI Keyboard and Numpad built by the Beta Community (http://decibel.ni.com/content/docs/DOC-1062) and modified it to add a "Clear" button to the keyboard and numpad. Please let me know if I implemented this in the best way.
Thanks for the help,
Kunal
Message Edited by bhatiak on 08-04-2008 03:55 PM
Attachments:
Array of Clusters4.llb ‏274 KB

My old tic tac toe example shows how to determine which square of a 2D array has been clicked.
http://forums.ni.com/ni/board/message?board.id=170&view=by_date_ascending&message.id=247044#M247044
You probably can adapt some of it for the arrays on the right. If the array can be scrolled, you also need to account for the "indexvals" offset.
The Layers controls is easiest, because you only show one element. Just read the "index vals" property to get the array element and parse the coordinates to get the cluster element.
btw: the small while loop on the right serves no purpose at all and acts just as a CPU burner. You can delete it without any change in functionality. Is there anything else to it?
LabVIEW Champion . Do more with less code and in less time .

How to change the tabbing order of an array of clusters?

How to change the tabbing order of an array of clusters? I have the cluster arranged in table in the front panel. The cluster element goes horizontal and array element goes vertically. When I press the tab key, the cursor goes to the next array element instead of the next cluster item (down instead across).
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Broken Arrow wrote:
Harold asked a perfectly reasonable and necessary question, but how is that a Solution ???
I believe it is called the Socratic Method.
Sea-Story time
I had the privledge of working for Ron Davis when he managed the Allegheny District of DEC. He was an ex-WO4 (Highest possilbe rank for non-commisioned officer in US Navy, required act of congress to confirm).
Ron never answered any question I ever saw presented to him. I remember a group of managers in a frenzy over some issue running to him to to see what he thought. He asked them a series of questions that lead them to the solution and soon they were smiling and slapping each other on the back as they walked away.
Who is that has a signature that read "it is the questions that guide us"?
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Brick Wall Problem: Array of Clusters, Size of array from reference

Good Morning Forums,
I have hit a brick wall with my application and I am hoping somebody can help!
I have an array of clusters of indeterminate size (the cluster is generic, data contained not relevant.).
Inputs to the VI are: a reference to the array, and a variant containing the data.
My problem is I need to determine the array size from these two inputs and I cannot find a way to do it!
If the array contained a standard data type I can use the class name property to determine data type, and the size of the array returned from "select size" property to determine dimension size. With this information i can cast the variant into the correct data type and use this to determine the size of the array. If the data is a cluster the class name simply returns "cluster" so I cannot cast the variant and therefore am unable to determine the size.
I am not worried about casting the data (once i determine the size this bit is no issue), I just need to determine the size (and preferably number of dimensions) of the array. Can this be done?
Cheers for any help
J
John.P | Certified LabVIEW Architect | NI Alliance Member
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John.P wrote:
Good Morning Forums,
I am not worried about casting the data (once i determine the size this bit is no issue), I just need to determine the size (and preferably number of dimensions) of the array. Can this be done?
Cheers for any help
J
There seem to be a couple of potential solutions.:
#1 if the varient is created within LabVIEW you can wite size(s) to a varient attribute. This would be pretty straightforward and easy to implement- I imagine you would have thought of that so you may not have access to the code writing cluster to varient and it gets a bit trickier.
#2 cast the varient to string and return string length- this should give you a measure of total size and you would need to know the size per element of cluster (just cast one instance of cluster array to varient and then to string with size and size++) but this only returns the total size of the array since nDim arrays are actually stored sequentially.
Hope this helped
Jeff

Call library function node with array of clusters using array data pointer

Hello all.
I am writing a LabVIEW wrapper for an existing DLL function.
The function has, as one of its parameters, an array of structs. The struct is very simple, containing two integers. I am using the call library function node to access it.
In Labview I created an array of clusters, where the cluster has two 32-bit integers as its members. So far, so good.
Now I have to pass this in to the Call Library Function Node. Here I am running into trouble.
I have used The topic in LAVA and The topic in the knowledge base as my primary sources of information, though I have read a bunch of forum topics on the subject too.
I do understand that I could write a new function which takes as a parameter a struct with the size as the first member and an array as the second, and I might just do this and have it call the regular function, but I was hoping to do it more simply.
According to the C file which LabVIEW generates for me from the CLFN when I choose "Adapt to Type" and "Array Data Pointer", the prototype it is expecting is:
int32_t myFunc(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, void data[], int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
And the prototype of the function in my DLL is
int borland_dll myFunc(DWORD handle, usint channel,
int FIFOnumber, struct mStruct *data, int numWords, int *actualLoaded, int *actualStartIndex);
This looks like a match to me, but it doesn't work (I get garbage in data). From the topic in LAVA referenced above, I understood that it would work. It does not.
If I cast data to the pointer-to-pointer I get when I generate c code by wiring my struct to a CIN and generating, then I seem to get what I expect. But this seems to work when I choose "pointers to handles" too, and I would expect array data pointer to give a different result.
Is there any way to get this to work directly, or will I have to create a wrapper? (I am currently using LabVIEW 2011, but we have customers using 2009 and 2012, if not other versions as well).
Thank you.
Batya
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OK, here is more detailed information.
I have attached the VI.
This is the code from the "C" file created by right-clicking the CLN and creating a "C" file.
When the parameter in the CLN is set to "array data pointer":
/* Call Library source file */
#include "extcode.h"
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, void data[], int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, void data[], int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex)
/* Insert code here */
When the parameter is "pointers to handles":
/* Call Library source file */
#include "extcode.h"
/* lv_prolog.h and lv_epilog.h set up the correct alignment for LabVIEW data. */
#include "lv_prolog.h"
/* Typedefs */
typedef struct {
int32_t control;
int32_t data;
} TD2;
typedef struct {
int32_t dimSize;
TD2 data[1];
} TD1;
typedef TD1 **TD1Hdl;
#include "lv_epilog.h"
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex)
/* Insert code here */
When the parameter is set to "handles by value":
/* Call Library source file */
#include "extcode.h"
/* lv_prolog.h and lv_epilog.h set up the correct alignment for LabVIEW data. */
#include "lv_prolog.h"
/* Typedefs */
typedef struct {
int32_t control;
int32_t data;
} TD2;
typedef struct {
int32_t dimSize;
TD2 data[1];
} TD1;
typedef TD1 **TD1Hdl;
#include "lv_epilog.h"
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex)
/* Insert code here */
As to the DLL function, it is a bit more complicated than I explained above, in the current case. My VI calls the function by this name in one DLL, and that DLL loads a DLL and calls a function (with the same name) in the second DLL, which does the work. (Thanks Rolfk, for helping me with that one some time back!)
Here is the code in the first ("dispatcher") DLL:
int borland_dll Load_Transmit_FIFO_RTx(DWORD handle, usint channel, int FIFOnumber, struct FIFO_DATA_CONTROL *data, int numWords, int *actualLoaded, int *actualStartIndex)
t_DispatchTable *pDispatchTable = (t_DispatchTable *) handle;
int retStat = 0;
retStat = mCheckDispatchTable(pDispatchTable);
if (retStat < 0)
return retStat;
if (pDispatchTable->pLoad_Transmit_FIFO_RTx == NULL)
return edispatchercantfindfunction;
return pDispatchTable->pLoad_Transmit_FIFO_RTx(pDispatchTable->handlertx, channel, FIFOnumber, data, numWords, actualLoaded, actualStartIndex);
borland_dll is just "__declspec(dllexport)"
The current code in the DLL that does the work is:
// TEMP
typedef struct {
int control;
int data;
} TD2;
typedef struct {
int dimSize;
TD2 data[1];
} TD1;
typedef TD1 **TD1Hdl;
// END TEMP
int borland_dll Load_Transmit_FIFO_RTx(int handlertx, usint channel, int FIFOnumber, struct FIFO_DATA_CONTROL *data, int numWords, int *actualLoaded, int *actualStartIndex){
struct TRANSMIT_FIFO *ptxFIFO; //pointer to transmit FIFO structure
usint *pFIFOlist; //pointer to array of FIFO pointers to FIFO structures
int FIFOentry, numLoaded;
usint *lclData;
usint nextEntryToTransmit;
// TEMP
FILE *pFile;
int i;
TD1** ppTD = (TD1**) data;
TD1 *pTD = *ppTD;
pFile = fopen("LoadFIFOLog.txt", "w");
fprintf(pFile, "Starting Load FIFO with %d data words, data pointer 0x%x, with the following data&colon; \n", numWords, data);
for (i = 0; i < numWords; i++) {
fprintf(pFile, "%d: control--0x%x, data--0x%x \n", i, data[i].control, data[i].data);
fflush(pFile);
fprintf(pFile, "OK, using CIN generated structures: dimSize %d, with the following data&colon; \n", pTD->dimSize);
for (i = 0; i < numWords; i++) {
fprintf(pFile, "%d: control--0x%x, data--0x%x \n", i, pTD->data[i].control, pTD->data[i].data);
fflush(pFile);
// END TEMP
if ((handlertx) <0 || (handlertx >= NUMCARDS)) return ebadhandle;
if (cardrtx[handlertx].allocated != 1) return ebadhandle;
pFIFOlist = (usint *) (cardrtx[handlertx].segaddr + cardrtx[handlertx].glob->dpchn[channel].tr_stk_ptr);
pFIFOlist += FIFOnumber;
ptxFIFO = (struct TRANSMIT_FIFO *)(cardrtx[handlertx].segaddr + *pFIFOlist);
//use local copy of ptxFIFO->nextEntryToTransmit to simplify algorithm
nextEntryToTransmit = ptxFIFO->nextEntryToTransmit;
//on entering this routine nextEntryToLoad is set to the entry following the last entry loaded
//this is what we need to load now unless it's at the end of the FIFO in which case we need to wrap around
if ( ptxFIFO->nextEntryToLoad >= ptxFIFO->numEntries)
*actualStartIndex = 0;
else
*actualStartIndex = ptxFIFO->nextEntryToLoad;
//if nextEntryToLoad points to the last entry in the FIFO and nextEntryToTransmit points to the first, the FIFO is full
//also if nextEntryToLoad == nextEntryToTransmit the FIFO is full and we exit without loading anything
if (( (( ptxFIFO->nextEntryToLoad >= ptxFIFO->numEntries) && (nextEntryToTransmit == 0)) ||
( ptxFIFO->nextEntryToLoad == nextEntryToTransmit)) && (ptxFIFO->nextEntryToLoad != INITIAL_ENTRY)){
*actualLoaded = 0; //FIFO is full already, we can't add anything
return 0; //this is not a failure, we just have nothing to do, this is indicated in actualLoaded
numLoaded = 0;
lclData = (usint *)data; //must use 16 bit writes to the module
//conditions are dealt with inside the for loop rather than in the for statement itself
for (FIFOentry = *actualStartIndex; ; FIFOentry++) {
//if we reached the end of the FIFO
//if the module is about to transmit the first element of the FIFO, the FIFO is full and we're done
//OR if the module is about to transmit the element we're about to fill in, we're done - the
//exception is if this is the first element we're filling in which means the FIFO is empty
if ((( FIFOentry >= ptxFIFO->numEntries) && (nextEntryToTransmit == 0)) ||
((FIFOentry == nextEntryToTransmit) && (FIFOentry != *actualStartIndex) )){
*actualLoaded = numLoaded;
//set nextEntryToLoad to the end of the FIFO, we'll set it to the beginning next time
//this allows us to distinguish between full and empty: nextEntryToLoad == nextEntryToTransmit means empty
ptxFIFO->nextEntryToLoad = FIFOentry;
return 0;
//we reached the end but can continue loading from the top of the FIFO
if ( FIFOentry >= ptxFIFO->numEntries)
FIFOentry = 0;
//load the control word
ptxFIFO->FifoData[FIFOentry * 3] = *lclData++;
//skip the high of the control word, the module only has a 16 bit field for control
lclData++;
//now put in the data
ptxFIFO->FifoData[(FIFOentry * 3) + 2] = *lclData++;
ptxFIFO->FifoData[(FIFOentry * 3) + 1] = *lclData++;
numLoaded++;
//we're done because we loaded everything the user asked for
if (numLoaded >= numWords) {
*actualLoaded = numLoaded;
ptxFIFO->nextEntryToLoad = FIFOentry+1;
return 0;
//if we reached here, we're done because the FIFO is full
*actualLoaded = numLoaded;
ptxFIFO->nextEntryToLoad = FIFOentry;
fclose (pFile);
return 0;
As you can see, I added a temporary diagnostic with the structures that were created in the "Handles by value" case, and print out the data. I see what is expected, whichever of the options I pick in the CLN!
I understood (from the information in the two links I mentioned in my original post, and from the name of the option itself) that "array data pointer" should pass the array of data itself, without the dimSize field. But that does not seem to be what is happening.
Batya
Attachments:
ExcM4k Load Transmit FIFO.vi ‏15 KB

Initializing data in an Array of Clusters

First, thanks in advance for reading this request.
Second, the situation:
I am using an array of clusters for process control.
The cluster contains a boolean, a typedef ring control, and two numeric controls (doubles).
Depending upon the user-requested operation I need anywhere from four to 20 cluster elements in the array.
Raw data for the two numeric controls are contained as elements in three different input clusters.
Each numeric control in each array cluster can use from none to four elements from the input clusters with various additions and subtractions (no mults or divs).
The boolean and ring can be set as constants for each element based on the user request.
Third, the request:
Is there a simple way to initialize the values in the cluster (and hence the array) without having to run wires everywhere?
I have been writing embedded code and PC applications for many years and am only recently tackling LabView.
In C, I would create a structure of the four elements and then create and array of structures.
The initialization would require a few lines of code.
I have tried using formula nodes (perhaps incorrectly). All they do is remove the Numeric blocks (like + and -), but they don't create the cluster.
I am sure that there is an easier way of accomplishing what I need to do, I am just too inexperienced to know what it is.
Any help or suggestions is welcome.
Thanks in advance.

Create a cluster with the desired default values as diagram constant, wire it to "initialize array" and wire the desired array size.
The output will be the desired construct that you could write to e.g. a local variable of the target.
I hope I understood you correctly. If not, attach a small VI containing your array.
LabVIEW Champion . Do more with less code and in less time .

Sort 1D array of clusters by the second element in the cluster

Hello Folks,
I need to sort 1D array of clusters [Point (X & Y)] using the second element (Y) of the Point cluster. Can anyone guide!!!!
Thanks.
Manu

I see Darren is a bit faster than me.
Here's my solution (LabVEWI 7.0), it is pretty similar.
Message Edited by altenbach on 03-22-200602:01 PM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
SortByElement2.png ‏4 KB
SortByElement2.vi ‏27 KB

Waveform Chart NOT allowed inside array of clusters; Dynamic plot stacking?

The NI Developer Zone has a VI that does something I want - dynamically
stack plots in a useful way. Unfortunately, I would like those plots
to actually be Waveform Charts and NOT Waveform Graphs (as the
documentation specifies but LIES!)
A little further experimentation shows you that it is seemingly not
possible to make an array of clusters that contain Waveform Charts!
Why?
Alternatively, are there any other ways to smartly show many signals at
once? I have found multiplots to be frustrating as it is difficult to
assign the number of plots once you start the VI (hence the existence
of Dynamic Stack Plots).
DynamicStackPlots here:
http://sine.ni.com/apps/utf8/niepd_web_display.display_epd4?p_guid=B123AE0CB938111EE034080020E74861

If you have LabVIEW 8.0, have a look at the new "Mixed Signal Graph"
(see e.g.: http://zone.ni.com/devzone/conceptd.nsf/webmain/C6B79FA61959D9D68625706E006F7462 )
LabVIEW Champion . Do more with less code and in less time .

Newbie Labview Question: Array of clusters

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