How to find Shared Variable Processes on RT target

It seems like it should be possible to query the SV Engine on a RT target for a list of all processes running and also the SV's within those processes.
The DSM (Distributed System manager) can do it, why can't I?

Also, you might also want to check out this KnowledgeBase.
Regards,
Claire Reid
National Instruments

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How to use shared variables?

Hello..
Can anybody please guide me in using shared variables... I'm learning LabVIEW 8.5.... But did not understand how to use shared variables... I tried to read web pages regarding shared variables but got confused.... So anyone can please help me...?
Thanks for any help from you...

You will have to give us the whole picture. What is your client computer; a PAC, desktop etc? What are you running on the client computer; a VI or an executable? Where are you going to deploy your library? On the host machine or the client machine?
If I assume that you are running a VI on the client machine and are depolying the library on the host, all you have to do is to create another shared variable and bind it to the variable on the host machine. You can do this by checking the Bind to Source option when creating the variable and browsing to the network item in options. Be sure to have the library deployed on the host side before you attempt to do this otherwise you won't be able to find the variable.
Adnan Zafar
Certified LabVIEW Architect
Coleman Technologies

How to use shared variables with native c programs

Hello
What is the way to use shared variables with native c programs?
I have a c/c++ program that uses the NIDAQmx C-API to perform measurements. Now I want to communicate to a LabVIEW program via shared variables.
Is there a C-API for shared variables as there is for the NIDAQmx functionality? Where can I find further documentation? The document "Using the LabVIEW Shared Variable" mentions that one "can read and write to shared variables in ANSI C", but there are no hints about how and where to look.
Thanks in Advance

Hi user42,
with CVI 8.0, you cannot create or configure shared variables. However, you can read or write to an already configured LabVIEW 8.x shared variable from CVI using the DataSocket API.
In order to do this you need to have and DataSocket 4.3 or higher installed.
Here's a forum post about using the DataSocket functions a LabVIEW Shared Variables:
http://forums.ni.com/ni/board/message?board.id=180&message.id=24569&requireLogin=False
With CVI 8.1 and Measurement Studio 8.1 it's possible to use Shared Variables via the Network Varaiable Library (check out the end of the "Network-Published Shared Variable" section within the "Using the LabVIEW Shared Variable" documentation and the following link).
Datasocket with LabWindows/CVI and LabVIEW Real-Time:
http://digital.ni.com/public.nsf/allkb/CC4343488413A2F586256E6200099638?OpenDocument
Daniel
NIG

How to identify the variable processing type

Hi Experts,
How to find the details of the variable whether it is filling with user exit or replacement path
Say i have a variable xxx , how to identify the above details.
Thanks,

use RSZGLOBV table in VNAM give your variable and VPROCTP will give you processing type

How to use shared variables to address multiple Watlow controllers on the same COM port

Hello,
I am trying to use LabVIEW 2010 to control 4 Watlow temperature controllers on one COM port. 3 are Model 96 and 1 is an EZ zone controller. Each controller has a unique modbus address, and I am trying to read from and write to individual registers (such as closed loop setpoint) using shared variables. I am getting return data when reading (although the data appears to be invalid), but am unable to change the value in the register by writing. How can I be sure that the Modbus server is sending commands to the correct controller?
Chuck
Solved!
Go to Solution.

Peter,
Thanks for the reply. I have actually solved that problem. I realized that the Modbus server address has to be the same as the controller's Modbus address.
I have, however, run into another problem. Perhaps you could help me with that. I have a system with 4 Watlow controllers, 3 are series 96 controllers, one is PID only and 2 are ramping. The 4th controller is an EZ zone. I am using RS485 for communications and the controllers are all wired in parallel for communications and power.
I have set up 2 Modbus servers for 2 of the controllers.
This is the first I have ever worked with Modbus based communications. I have successfully programmed using the Modbus read/write VIs, and am wanting to move to shared variables. My questions right now revolve around addressing, Modbus I/O servers and COM ports. Specifically, at this point, I know the addresses need to match up between the server and the slave device (Watlow controller in my case), how many servers can I create and use on one COM port? If the number is limited, is there a way I can specify an address that I want the server to talk to? Will the broadcast mode work to request data values from the controllers?
I'd appreciate any information you can help me with, or if you could point me to some sort of concise 'How-To' for Modbus communication.
Thanks.
Chuck

How to read shared variables inside event structure ?

Hi,
I have a problem that my shared variables do not update inside event structure. The program(s) I am trying to get working is seen in the attached screenshot. It works as follows:
0. I start the vi that is unsquared.
1. I write a string to a shared variable using vi in red square. I make sure that its updated using write-wait-read.
2. I run the other vi (blue square), this changes the boolean shared variable.
The unsquared vi has been running the whole time, it has event structure bind to boolean shared variable change (the one in blue vi). After I have runned the blue vi, the unsquared vi should change the indicator values to match the ones in red vi. However I have to start the blue vi multiple times to get it to change, sometimes even 6 times.
Also, when I change the value in red vi to a third value and start blue vi multiple times, the unsquared vi shows all the variables. I.e. I put "cat" to red then start red, put "mouse" to red then start red,... and then start clicking blue... Unsqured shows cat, mouse,..., dog (dog is the default).
How can I force the shared variable to update inside event sructure. I want the current value of the variable, not some historical values.
Attachments:
Screenshot-5.png ‏108 KB

Found the buffering... disabling it solved the problem... thanks.
FYI, there is another solution that I just found out... attached. Adding timeout to the event structure and the variable read outside the event structure... This makes the shared variable strings (one that is read outside and the otherone that is read inside) different.
Could someone explain why the variables are in different state even if they are used in the same place and looped with 10ms intervals?
Juha
Attachments:
Screenshot-6.png ‏110 KB

How to find the Variable in the form

I am having in which it is populating one forms "Display Variable"........but I don't know from where it is getting populated......Since Because there are lots of procedures and Trigger written and there are around 150 items on the forms...............i feel it litle inpractical to search for each and every item in the form..................
Please help me in searching .......how to find where that item is getting popultaed from?

I am having in which it is populating one forms "Display Variable"I could not understand this sentence...please make it clear...
but I don't know from where it is getting populated.And also this one. when it is getting populated. At the time of query or when you are opening form?
Anyway if you want to search for specific item in you code then go to Edit>Find in SQL / PL SQL and enter the field name which you want to search in your code. It will show you all the triggers where you mentioned that item in your code.
By the way hi ;)
-Ammad

How to update shared variables

Hi, I have a VI that opens an text file and reads some information from that page. That information should be copied to shared variables. The problem is that I have 160 shared variables and I don't want to drag them all from project explorer to Block diagram and wire them all. Is there any other way to update that data to shared variables? I can easily open and read data with couple of while loops. I'd really be thankful if someone could help me.
Mika

I do need all 160 variables. I have to make a sequencer.With cFP modules and laptop is ment to specify sequences needed for testing some equipment. I have 16 digital inputs and 16 digital outputs and 8 analog inputs. Those shared variables specify which channel is ON and for how long, and the delay of the channel. There is also variable that tells if channel is in use or not. One variable is channel factor, which tells how many cycles there will be in that cycle time. So if one channel needs only 5 variables, those 40 channels need 160-200 variables. Shared variables are specified in the user interface and then cFP module can easily read them. In user interface there is also the possibility to open a file that have variables specified earlier. In that point I need to open a text file and update the data to shared variables.
Mika

How to use shared variables to measure analog input

Dear All,
I am using Real time remote system. I am using PXI-6259 card, PXI-8184RT controller and PXI-1031 Chassis.
I want to use shared variable to measure and analog Input(voltage) from
an analog input Channel. I tried attaching it with the physical
channel using the bind to source option but it idoes not seem to work,
can any one give me any suggestions?
Screen shot of this is available.
I tried using the Acq and graph example and deployed it to the RT but
the Sine wave I input in the measurement channel becomes highly
distorted when I see it in the host.vi, there is also a Screen shot of
this also. Is there any other option.
What am I doing wrong? all suggestion are highly welcome.
Thank you.
Sincerely,
Munir Afzal Bhatti.
Attachments:
SV2.jpg ‏2305 KB
SV3.jpg ‏2305 KB

You will have to give us the whole picture. What is your client computer; a PAC, desktop etc? What are you running on the client computer; a VI or an executable? Where are you going to deploy your library? On the host machine or the client machine?
If I assume that you are running a VI on the client machine and are depolying the library on the host, all you have to do is to create another shared variable and bind it to the variable on the host machine. You can do this by checking the Bind to Source option when creating the variable and browsing to the network item in options. Be sure to have the library deployed on the host side before you attempt to do this otherwise you won't be able to find the variable.
Adnan Zafar
Certified LabVIEW Architect
Coleman Technologies

How fast can shared variable update?

Hi,
     According to online documents shared variable engine update at 10ms or forced by flushing command. But I tested the following two program and can not get the shared variable updated:
      Thanks fo rhelp!
      Tom
Attachments:
test_program1.png ‏20 KB
test_program2.png ‏20 KB

Hi,
     I don' use NSV to transfer large amount of data between RT and host. The actual application is as follows:
      I also would like to test how fast the NSV update rate and how the flush vi works. I test two programs and did not match the number in the documents.
    Tom

VI cannot find shared variable in engine despite successful deployment

I am unable to use Shared Variables to communicate between VIs located on my PC and the VIs located on my cRIO-9014. This is a new development as I have been running the same VIs for over a year without this problem. The only recent development is that the IT department at my company installed new virus protection software and changed some windows firewall settings on the PC that I am using. This problem first began as soon as I got the PC back from IT. I have since unblocked LabView in Windows Firewall but that has not fixed the problem. The error I get every time I try to read a shared variable on the real time target is:
Error -1950679035 occurred at Shared Variable Read in RT Interface.vi
Possible reason(s):
LabVIEW: (Hex 0x8BBB0005) Unable to locate variable in the Shared Variable Engine. Deployment of this variable may have failed.
I have redeployed all of my shared variables and according to LabView the deployment was successful, yet I still get this error every time. Is it likely that something the IT department did with the Antivirus/Firewall software has blocked communication between the cRIO-9014 and my PC? I have used Measurement & Automation Explorer to check communication with the device and as far as I can tell everything seems fine.

After adding LabVIEW to the exceptions list of Windows Firewall, my issue seemed to be cleared up. I am now getting the same error message once again, but now I get it every time I run a VI with shared variables and it actually pops up an error message asking me to continue or stop. Again, according to LabVIEW the shared variables deployed successfully. I looked at the two KB articles that were posted and it seemed like this error has three causes:
1-Unsuccessful deployment - everything seems to have deployed
2-Firewall Issues - were taken care of to fix my original problem
3-Shared Variable Engine not running
I've looked around and I found a reference to 'repairing' the shared variable engine but not a guide for how to do that. I have opened variable manager (I am using LabVIEW 8.5) and have stopped and started the shared variable engine with no effect.
What are steps I can take to ensure the Shared Variable engine is running properly?

How to find unused variable through sequence

Hi,
I would like to know if it is possible to find unused variable through sequence in order to suppress them ?
Thank you

Hi,
If you're fixed on that version of TestStand for a while (for whatever reason) and you see this situation coming up again, you could always build a small tool to automate the process.
From the current sequence file's handle, you could traverse all the locals and file globals to make a list of all variables and then search the sequences step by step to see if they're in use.
What this won't tell you is if any code modules or custom step types are directly accessing those variables through the sequencecontext handle so removing them can cause issues.
A secondary approach is to cut all the locals (or whatever the variable scope is) in to a new sequence file (or work with a backup version of your sequence file) and delete them from the existing file and see what errors get thrown up.
Finally, as Doug suggests, to get a latest copy of TestStand on to another machine, you could download a trial version and work with that if it's a one off. After all - if you find the sequence analyser feature that useful, it's a great reason to consider your upgrade policy / timing in the future anyway!
Thanks
Sacha
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How to find out what process touched a file

I am currently running Leopard 10.5.7 on a MacBook. Some of my system files' permissions keep getting screwed up. It happens randomly, and when it does I have to repair permission and reboot the computer to fix it. I am trying to isolate the problem. Is there a way to find out what processes or applications touched a certain file? thanks.

Tony:
Did you try repairing your keychain?
Look in your 'Utilities' folder for the 'Keychain Access' application.
Run it and use the 'Keychain Access/Keychain First Aid' menu...follow the prompts. After repairs, restart and see if the situation improves.
If you are determining permission repair status on a repeated basis by simply doing a repair and reacting to the immediate report there, you may be chasing ghosts.
If you are encountering legitimate issues when running various apps, you may need to check the basics. If there are other users on the machine or you have moved standard applications to custom locations you may have to simplify your overall machine's configuration and go from there.
Good luck in any case.

How to find out the process chain

Hi folks
Hope every one is doing good..!
in sm37 my job is running (ABAP program) which is in process chain, but i have to find out the process chain name..!
Could any one help me on this..!

hi,
in SM37 select the job status as active and execute it, in the next screen you will find only active jobs select your job (ABAP Program) click on step - > in th next screen put the cursor on the job -> select Goto option in menu bar click on variant it gives you the field names and desc like chain name, variant etc information.
Regards
Sankar

How to find the Variable

Hi,
I searched in google i could not get proper anser.
my question is
how to find the varient is created are not. and also i am intrested to learn how to creat the variant...
Thanks and regards,
Kesava.

hi ,
i am intrested to learn how to creat the variant...
For creating varient just run ur program,
And enter the values into the inpur parameters or select-options.
then press the save button,
after it will display another screen which will ask about the varient name and its discription, fill it and save it,
your varient will created.
Same way u can create another varient also
how to find the varient is created are not
please refer below blogs:
[Blog1|Create variants through ABAP;
[Blog2|How to set up standard variant in ABAP report;
thanks,

How to find Shared Variable Processes on RT target

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