Real time processing in formula node

hello all,
I'm using LabVIEW for data acquisition of an analog signal.My sampling frequency is KHz. Now if I've to process these data's in formula node what type of variable I need to define in formula node.?
For example,if I want to add add all the magnitudes of the samples and store the sum after each sample squired.How do I write the formula node?
I'm an amateur in labVIEW. amateur guide.
Thanks in advance.

pramodantony wrote:
Now if I've to process these data's in formula node what type of variable I need to define in formula node.?
Who forces you to use the formula node? You simply need to process the data, the means should be irrelevant.
Acquired data in LabVIEW can be of many forms (arrays, waveforms, dynamic data, etc.). Can you show us what you have?
LabVIEW Champion . Do more with less code and in less time .

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Acrobat Plugin Can be involved in Real-time processing

Hi,
I am implementing an acrobat plug-in solution for color separation and generation of PRN file for the given PDF file.
Is the Plugin Architecture is good for the real time processing and RIPPIng? I have a doubt like the Acrobat Process
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First and foremost, Acrobat can NOT be used on a server, right? So this is going to be a user-invoked process, correct?
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From: Adobe Forums <[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
Date: Wed, 21 Sep 2011 07:29:28 -0700
To: Leonard Rosenthol <[email protected]<mailto:[email protected]>>
Subject: Acrobat Plugin Can be involved in Real-time processing
Acrobat Plugin Can be involved in Real-time processing
created by skrasheed<http://forums.adobe.com/people/skrasheed> in Acrobat SDK - View the full discussion<http://forums.adobe.com/message/3929688#3929688

Real-time process slowly filling up Postgres DB space

I have a real-time job which takes data from a JMS queue, processes the data, and then applies inserts/updates to an Oracle DB. In the task definition for the process Results drill down is set = "None" yet the Postgres DB grows substantially as the job runs. Also the following SQL seems to find a row per JMS message processed...
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Cheers
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It looks like we're going to have to - Postgres has just died...
WARNING: 22-May-2014 04:24:27: Unable to index table : 'DNM_819_776_1_ingr'
WARNING: 22-May-2014 04:24:27: A database error has occurred : ERROR: could not create relation base/25589/3549571: File too large. (Code: 200,302)
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HELP: Run-time array dimension in LabVIEW formula node

I need to dimension an array at run time within a formula node as follows:
int32 i,N;
N = sizeOfDim(inputArray,0);
float64 outputArray[N];
for (i = 0; i outputArray[i] = myfunction(inputArray[i]);
However, LabVIEW complains "Formula Node: index list expected". On the
other hand, if I say
float64 outputArray[1000];
LabVIEW is perfectly happy. But that's not what I need to do! Is there
an alternative
way of accomplishing my goal?
BTW, I've tried calculating N outside the formula node and then
presenting it as
an input with the same results. I've got a bad feeling that run time
array dimensioning
just isn't allowed.
TIA,
Hugh

Can't you just use the Initialize Array function outside the formula node and pass that instead?

Continuous data acquisition and analysis in real time

Hi all,
This is a VI for the continous acquisition of an ECG signal. As far as I understand the DAQmx Analog read VI needs to be placed inside a while loop so it can acquire the data continously, I need to perform filtering and analysis of the waveform in real time. The way I set up the block diagram means that the data stays int the while loop, and as far as I know the data will be transfered out through the data tunnels once the loop finishes executing, clearly this is not real time data processing.
The only way I can think of fixing this problem is by placing another while loop that covers the filtering the stage VIs and using some sort of shift registeing to pass the data to the second loop. My questions is whether or not this would introduce some sort of delay, and wether or not this would be considered to be real time processing. Would it be better to place all the VIs (aquicition and filtering) inside one while loop? or is this bad programming practice. Other functions that I need to perform is to save the data i na file but only when the user wants to do so.
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Solved!
Go to Solution.

You have two options:
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Your choice really depends on the processing that you plan to perform. If it is processor-intensive, it might introduce delays as you mentioned.
I would reccomend you first try to place everything in the first loop, and see if your DAQ buffer overflows (you can monitor the buffer backlog while its running). If so, then you should decouple the processes into separate loops.
Regarding whether or not "this would be considered to be real time processing" is a loaded question. Most people on these forums will say that your system will NEVER be real-time because you are using a desktop PC to perform the processing (note: I am assuming this is code running on a laptop or desktop?). It is not a deterministic system and your data is already "old" by the time it exits your DAQ buffer. But the answer to your question really depends on how you define "real-time processing". Many lay-people will define it as the processing of "live data" ... but what is "live data"?

TCP/IP Connecting with Real Time Controller

I have a host running Labview on a windows XP and a realtime embedded controller on a pxi chassis that acts as the server. When the realtime is started it automatically goes into listen mode and listens for a connection from the host. The host opens a connection. After a valid connection is open the Real-Time side goes into a TCP_Read and the host can then send commands that the real time processes and sends to the FPGA on the pxi-chassis.
Now the problem I'm having is how to handle the case when a TCP connection is lost. I can have the TCP_Read on the real-time error on a time out and then go into a listen mode but this isn't very logical because then the host will have to reconnect each time a time out occurs. So if I make the TCP_Read timeout be infinite and if the connection is lost (let's say I unplug the ethernet cable and re-plug it back in) then I cannot recover from this and the Real-time will need to be re-booted.
I've tried to send the Real-time into listen mode if the error code is other than a timeout error (code 56) and have it go back to TCP_read mode if it is a timeout error. But if the connection is lost by means of a physical way (such as me pulling the ethernet wire and plugging it back in) then the Real-Time never sees that the connection is invalid. The host on the other hand can detect it bc it will get an error when it's trying to write?
So my is:
Is there any way to prevent an infinite loop that needs a reboot and at the same time prevent the host from reconnecting every time there is a timeout?

Hi SJeane,
I apologize for taking so long to respond, but I wanted to test this on my end. In doing so, I realized that using the RT Reboot Controller.vi after the connection is lost does not work because the message to reboot cannot be relayed to the target without communication! Thus, to solve this problem, we have to approach it a different way. You mentioned that you tried programmatically clearing errors, but did you try to reestablish connection after clearing the errors? I tested this on my end with a FieldPoint controller, and the attached VIs resumed operation even after unplugging/replugging the Ethernet cable (no reboot). Will this solution work for you?
Peter K.
National Instruments
Attachments:
Reestablish.zip ‏39 KB

CRIO-9067 Real-time unexpected error restart (Hex 0x661)

Hi all,
I recently moved to LV2014 SP1 and NI-RIO 14.5 to support development of a cRIO-9067 Linux RT controller. The past two days of development have seen LabVIEW crash numerous times (eight at last count), along with numerous VIs being in an undeployable state due to some unseen error (there's no broken run arrows anywhere, and a LV restart seems to cure what was broken).
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LabVIEW: (Hex 0x661) The LabVIEW Real-Time process encountered an unexpected error and restarted automatically.
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Below is a screenshot of the software installed on the controller:

You should be able to access the error logs on your controller through MAX.
Is There an Error Log File for My Real-Time Controller?-http://digital.ni.com/public.nsf/allkb/E734886E027D0B6586256F2400761E30?OpenDocument
How Do I Locate the Error Logs on My cRIO if I Don't Have MAX? - http://digital.ni.com/public.nsf/allkb/9D2F9D4F8C834D678625766D00633837
Could you post the error log files for the Compact RIO targets that reproduce the error?
It’s possible that a memory leak is occurring someplace in your program that causes the crash.
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Additionally, is this crash repeatable with other code, say a simple shipping example? I would imagine that the crash is related to a routine called in your program, but it’s possible there is a corruption in the software installation on your target.
Also, what is the ProcessCommandMessage.vi responsible for/doing in your application?
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Applications Engineer
National Instruments

Real time JVM Implementation

Hi All,
We some students of our university would like to implement Real time JVM on Linux.
We do have a solid idea on linux as well as on Java. But this is a very new and interesting topic.
Can anyone help me how to start the assignment i.e. implementation of real time jvm on linux.
Thanks and Regards
tapas

Just guessing...
There are only two impacts to real time processing in java.
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Finally I suspect that if you do a literature search you would be able to find some papers on this subject.

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Venkata,
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Process Chain for Real Time Demon

Please help I am stuck I followed the step by sdn but this is missing in step. how to create now process chain.
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DSO CONNECTED TO dATASOURCE via Trans,
Real Time IP
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null

Hi
refer to this
CREATION OF PROCESS CHAINS
Process chains are used to automated the loading process.
Will be used in all applications as you cannot schedule hundreds of infopackages manually and daily.
Metachain
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1. Start ( In this variant set ur schedule times for this metachain )
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1. Start
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3.X
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/_____________________|
Infopackge1C(Txts)______|
\_____________________|
\___________________|
__\___________________|
___\__________________|
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__________|__________
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Desing requriment for processing the IDOC in real time

hi Gurus,
we have a requirement to design for processing the IDOC in real time i.e.all the IDOC must be store and process for give time line with out using BPPM tool.we have suggested to use cache storage or storing the files in file adapter.
please suggested good process with out compromising the Performance of PI.
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hi Raj,
Please find the example below for your reference
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system A sends multiple files based on time(daily or weekly) and real time( as an when the record created) to systerm B (CRM) in the form of IDOC Via. PI
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Do I have to use LabVIEW Real Time with a reflective memory node?

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Hi AEI,
I have worked with that card briefly before. It has a Visa based driver and RT isn't required. However, I haven't worked with the card on a non-rt system and am not sure if there any issues to be aware of.
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Bug: Built Real-Time app won't run if it accesses a typedef'ed shared variable node

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Yes. See the following thread.
Paolo
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DPC spike at Windows automatic maintenance startup. Can not leave the computer alone processing real-time streams.

This is what happens when I leave the computer idle for a while and the Windows automatic maintenance starts:
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Hi Fjtorsol,
We hope your issue has been resolved, if you've found solution by yourself. you could share with us and we will mark it as answer.
This high Deferred Procedure Call (DPC) latencies are usually caused by certain drivers, if it is caused by automatic maintenance, please re-check your task schedule which is marked as “when computer is idle”. As what has been suggested by MVP ZigZag, please
use the Microsoft Windows Performance Analyzer from the Windows Assessment and Deployment Kit (ADK) to identify the cause of any DPC latency spikes.
https://www.microsoft.com/en-gb/download/details.aspx?id=39982
DPC CPU Usage Summary Table will open containing a list of drivers/program. This list is already correctly sorted (by the Actual Duration column). The process on the very top of the list is therefore likely to be the cause of your problem.
Regards
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Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact [email protected]

Real time processing in formula node

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