Can i fire Shared Variables' "Bad Status" alarm artificially?

And what shall I do to experience 'Bad Status' alarm. SVE is running on Windows platform PC.
Solved!
Go to Solution.

One shared variable one heat level sensor(DS18B20).
I want use it's "Bad Status Alarm" to alarm person on duty -
the corresponding DS18B20 sensor was failure!
But what shall I do to experience 'Bad Status' alarm first?
Don't know why, don't know the solution. Is that right?
Why there is no example project about "Bad Status Alarm"?
http://forums.ni.com/t5/LabVIEW/what-s-the-meanning-of-bad-status-in-DSC-alarm-config-for-Shared/m-p...
NI call this "answer"?

Similar Messages

Can we use shared variable in main report's crosstab

Post Author: sangi
CA Forum: General
Hi,
I have a main report with subreport (in Group footer), crosstab (in Group header).
For cross tab calculation, I need a value from subreport to be passed to main report's crosstab.
I could pass the value using shared variable.. but since the crosstab is in group header , I am not able to get the values .. .it is all 0....
Please help me

Post Author: wapper
CA Forum: General
To my best knowledge, what you ask for is impossible. The subreport in group footer is going to be evaluated during the last pass, so you are too late to get values into the group header. I could suggest creating a copy of your subreport and placing it (possibly hidden) into the group header just to get the values you need... But this would be the last measure if you really can't do anything else to achieve same goal. Wapper

Can not read shared variable on cRIO, error -1950678968 nitaglv

Hardware setup:
Laptop
Laptop connected via USB to a frammer garber.
Laptop IP: 192.168.0.2
NI vision calculating a diameter and setting a network varaible
cRIO
cRIO connected to the laptop
cRIO IP: 192.168.0.1
Project has the shared variable in the cRIO library
NI vision writes to the variable on the cRIO. I can see the variable properly updating in system manager on the cRIO. I can also run a VI in my computer that shows the variable properly updating. But...... When I read the variable with a VI running on the cRIO, I get the folowing error and the variable never updates:
Error -1950678968 occurred at Shared Variable in Main.vi
Possible reason(s):
LabVIEW: Failed to load nitaglv, which is required for Network-Published Shared Variables.
This error or warning occurred while reading the following Shared Variable:
\\NI-cRIO-OASIS\cRIOVariableLib\BubbleDiameterFromVision
\\192.168.0.1\cRIOVariableLib\BubbleDiameterFromVision
(I do not get any errors at deloyment)
So everything (NI Vision, a VI deployed on the laptop, NI Distributed System Manager) can see the variable on the cRIO being updated by the NI Vision.... Except for a VI running on the cRIO.
I have verified that I have Network Variable Engine and Variable Client Support for RT installed on the cRIO. I have tried reinstalling all s/w on the cRIO. Tried rebooting all. And talked in a nice, positive, reassuring voice to the chassis.

Hi!
I just had the same issue with my cRIO 9073 using NI RIO 3.6.0.
The problem is not caused by a corrupted project, but the improper installation of the OS on the target. There is nothing you can do using the SW installation wizard in MAX, as it does not matter if you intall a full RIO SW, minimal or custom.
You have to install the full install or a custom one with Shared Variable support. Then you have to FTP to the cRIO, and manually edit the "ni-rt.ini" file located in the root of the controller.
Make sure you have a line in the "[MODULE VERSIONS]" section which shows the version of the nitaglv.out file. (The problem is caused because this dll is not loaded when you try to access a SV) Mine looks like nitaglv.out=6.3
Then you have to insert "nitaglv.out;" without quotes to the [LVRT] section's StartupDLLs key's value. I did it after the taggerrt.out name. So my key entry now looks like this:
[LVRT]
StartupDLLs=nisysapirpc.out;NiViSrvr.out;NiRioRpc.out;taggerrt.out;nitaglv.out;sysstatepublisher.out;
memoryChecking=False
LABVIEWRTDir=/c/ni-rt/system
PATH=/c/ni-rt/system/;/c/ni-rt/;
CDIntervalTicks=55
WebServer.Enabled=FALSE
RTTarget.VIPath=/c/ni-rt/startup
RTTarget.IPAccess=+*
RTEnetRcvMode=2
RTCPULoadMonitoringEnabled=True
RTTarget.ApplicationPath=/c/ni-rt/startup/startup.rtexe
server.tcp.access="+*"
RTTarget.LaunchAppAtBoot=True
RTTarget.EnableFileSharing=True
server.tcp.serviceName="Main Application Instance/VI Server"
After you are done with the editing, you have to save the file, and overwrite the original one. You have to reboot the controller for the modification to take effect.
After this you will be able to host your variables on the cRIO and also read/write them from the application running on that same target.
I hope this will help for you too.
Regards,
Peter

Does OPC UA Shared Variable Server support Alarm&Event and historical access?

OPC UA Shared Variable Server is a sample code and resides at https://decibel.ni.com/content/docs/DOC-25602
It seems to support DSC <-> OPC-UA tag synchronization.
But does it support alarm&event and historical access?
I tried to open it with LabVIEW 2012, but lots of VIs were missing in the code, and I am not familiar with DSC and OPC-UA.

Hi iCat,
From your post on the example itself, a colleague of mine responded with: "This uses the OPC UA server included in DSC 2011 SP1 which does not include direct support for Alarms and Events. However you could use this idea to synchronize to shared variables on a Windows host which could have those abilities enabled."
So it looks like it doesn't directly do this.
Matt S.
Industrial Communications Product Support Engineer
National Instruments

Labview 8.2 can't write shared variable

Hi!
I developed LV 8.2 program using shared variable (network published) variant type. After extension of variable the vi charased after writing value in shared variable. If i changed shared variable from network published to single proces type the vi working OK.
Attachments:
problem.jpg ‏23 KB

Hello,
I have created a network published shared variable of type variant, and successfully written to and read from it. Can you also post a snipet of your code which reproduces the problem?
General things to try in case include:
1. undeploy and redeploy the shared variable.
2. repair your LabVIEW installation - this will repair the variable engine, and I know of at least one case where this helped after it was corrupted.
I hope this helps!
Best Regards,
JLS
Best,
JLS
Sixclear

Can't connect shared variable engine

HI All,
LabVIEW 2009 + DSC
We have one test laptop on our local network. Other developers read values of some variables from that laptop. Now we have a new developer and computer. When we try to browse test laptop from network it can be found but we can't see any libraries there. This is done by using distributed system manager. PING is ok, and there is "no" firewall or virusradars. Other developers can connect that laptop well and there is no problems. Does anyone have good advices to solve this issue?
BR, Jim
Solved!
Go to Solution.

Re-installation solved this.

URGENT DSC: I can write to shared variables but CANNOT read them?

hello everyone,
I'm using DSC to communicate with a DELTA DVP28SV PLC. I managed writing to a coil to to turn a fan on, and I also wrote to a register.
However, when i tried to read the coil (same coil i just turned on) or when i tried to read a register that im very sure has values (the register where i configure the modbus parameters), it would return ZERO, even when i tried to read the register that i just wrote into the reply was zero (I am sure that writing to the register was successful because i made the specific value that i wrote to the register a condition to turning a light on).
So, anyone knows why this could happen?? the Registers are Read/Write. I thought it could be that the scan time in the PLC is too short so i added delays but anything i read still gives zero back. ideas? can anyone help me with this?
here's the PLCs application manual in case it matters : http://www.delta.com.tw/product/em/control/plc/download/manual/DVP-PLC-Program_O_EN_20120416.pdf
Solved!
Go to Solution.

here: capture.png shows the results i get
Attachments:
diagram.PNG ‏32 KB
Capture.PNG ‏10 KB

View alarm status of shared variable

Hello:
I need to know the alarm status (I mean, if the shared variable is currently alarmed) of some shared variables hosted in a Compact Fieldpoint Controller.
I've seached for options on how to do this (like searching for a property through a property node of the SharedVariableIO class) but haven't found a succesful method to do it.
Anybody knows how to do that?
Thanks in advance!
Robst.
Robst - CLD
Using LabVIEW since version 7.0

Hola Robst, para ver las propiedades de una variable lo que necesitas hacer es habilitar el porperty node para que acepte como entradas las constantes de Variables Compartidas. Para que property node acepte esta referencia como entrada tienes que decirle que en clase es una variable compartida. Para seleccionar la clase da clic derecho sobre el nodo, y ahí aparece en el menu class. Después selecciona Shared Variable. Una vez que tengas la Shared Variable vas a tener todas las propiedades, sin embargo aquí no hay una propiedad que diga si está o no activa la alarma este nodo más bien te permite saber la configuración de la alarma y modificarla.
Aquí hay tres opciones sencillas para sacar esto. La primera es utiliza solo una variable y conectala al Read Alarms, o Alarm Status a partir de aquí puedes saber si existe o no alarmas.
Con el de Read Alarms si el arreglo regresa vacio es que no hay alarmas. Con el de alarm Status hay una elemento del Cluster que te indica que si hay alguna alarma.
Ahora otra opción es utilizar Read Alarms y de ahí extraer cuales son las alarmas.
Saludos
Message Edited by BeCeGa on 12-18-2008 05:43 PM
Benjamin C
Senior Systems Engineer // CLA // CLED // CTD
Attachments:
Alarmas2.PNG ‏21 KB
Alarms Variables.vi ‏22 KB

Change Alarm / Quality of Shared Variables for I/O Server

How does one set the Bad Status of a Shared Variable in 2009?
IE). I have a custom device that communicates via TCP/IP. I wrote my own I/O server that handles this communication and publishes a set of Shared Variables that my Main Application displays on a screen. These variables are all doubles and hold pressures and temperatures. If my I/O server in labview loses communication I would like to be able to set the status of the variables to bad so they will set off an alarm. In our main application we have colour indicators that are able to display this status. For example the background goes yellow for all indicators that are in "HI" alarm status, red in "HI HI" and orange when "Bad Status" (disconnected).
We were able to accomplish this using LabVIEW 7.1 DSC, by creating a VI to register all our "Tags" and a VI to run the server. The server vi's that came with 7.1 allowed us to set the quality when writing to the server item. Therefore when the device was disconnected or failed we could set the bad status and use the DSC system to log an alarm and use the alarm features to colour code our indicators.

None of the Shared Variable IO Properties can be configured to allow you to set the alarm. You can only configure the properties such as turning the possibility of the alarm status on/off and the priority, name etc. You do not have the ability to indicate that this shared variable is in alarm because your custom server has encountered a problem. I've talked to tech support about it and I've been informed that this was something that was removed when the shared variable engine was introduced. I've been told informed that the recommended alternative is to create an additional boolean shared variable that will contain the status of the items, or to write some sort of unique garbage value to the actual tag value to indicate there is a problem with it.
I now have to come up with a new way of providing this information. I just find it will likely be a poor programming choice because now my entire system will have to handle "tags" differently based on what hardware is being used. (IE) if its coming from a custom I/O device or from an OPC / Modbus etc capable device.

How Can i retain the Shared Variable Values after PC rebooting

Hi all,
I am facing a paculiar problem with Shared Variables. I have an application in which shared variables are used for data communication.
One of the application requirement is to retain the variable values eventhough PC is rebooted or started after crashing.
As per the my understanding, the variable values will retain eventhough the PC is rebooted. But here i can observe a paculiar problem like some library variables are retaing the values while some others not. I enabled logging for all the variables.
I tried many ways. like logging enabled, logging disabled, changing variable names, changing process names etc... But i am not getting a consistent behaviour.
I hope some you can help me in solving this issue.. "How Can i retain the Shared Variable Values after PC rebooting"
Thanks and Regards,
Mir

Hi Blackperl,
Thanks for the post and I hope your well.
What do you mean by not getting consistent behaviour.. this will all depend on excatly when the crash happens i.e. before the write or after.
Surely a better method would be to log the data to a file during the reboot...
I beleived the value read back
will be the default value for the shared variable's data type.
The LabVIEW DSC 8.0 module adds more functionality to the shared variable, including initial values and alarms.
If you enable an initial value on a shared variable, when the variable
engine comes back on-line it will default to this value. Setting a bad
status alarm for the shared variable is also a good way of handling
this type of event. Additionally, if you are using a LabVIEW Real-Time
target such as Compact RIO or Compact FieldPoint, it is appropriate to
consider hosting the shared variable engine on the real-time target.
These devices have watch-dog capabilities and are typically the
hardware controlling the critical pieces of an application. Most
Windows or PC-based targets do not have these fail-safes.
I guess, if you could explain to me again that would be great. From my point of view, if I have a cRIO and a Windows PC. If the windows PC crashes, the cRIO will still update its shared variables. Then once the PC has started up its own shared variable engine, and the bindings are loaded, it will once again continue to update its copies of the variables.
Please let me know what you think,
Kind Regards,
James.
Kind Regards
James Hillman
Applications Engineer 2008 to 2009 National Instruments UK & Ireland
Loughborough University UK - 2006 to 2011
Remember Kudos those who help!

Shared variables update in QuickClient but not in Variable Manager

Greetings,
I am using LV 8.6 Developer with the DSC module installed. Also, I'm using WinXP Service Pack 3.
I am trying to create a VI that will interact with an OPC server connected to some equipment.
I've created shared variables to read the value of tags in my OPC server exactly according to the instructions on this page:
http://zone.ni.com/devzone/cda/tut/p/id/6346
For some reason though, the value of the shared value never updates to reflect the value on the server.
When I follow the tag on the OPC QuickClient, it updates just fine, but somehow the value of the shared variable isn't updating.
I also tried retreiving this data using the DataSocket method in the "Multiple OPC Items Monitor.vi" example, but running that VI crashes LabView every time.
Also, I can create a shared variable and write to tags using a VI, but I can't read them.
It seems like I'm *this* close to getting the shared variables to work. Any suggestions?

Hi Rob,
To answer your questions...
DataSocket: NI doesn't give me the option to investigate the error when I restart the program. I did a search for .cpp files, but none turned up. I did collect the error report that Windows generates, and I attached it. I'm not sure if that would be something useful or not.
SharedVariables: I went to use the Distributed System Manager to take a look at the variables. For both my shared variable as well as the tags on the I/O data source, the data type is listed as "advanced" and the quality is "unknown bad." I collected the logs from the I/O server and attached them. Oddly, when I look through there, I see some Quality=BAD and some VT_ILLEGAL flags. The deadband is set to zero, and the update rate is 1,000ms.
Also, I've configured the DCOM and Local Security Policy settings as described in numerous support articles, and my Windows Firewall is turned off. The OPC server and LabView reside on the same computer.
I suppose the confusing thing is why the QuickClient works fine, but the SVE doesn't.
I've tried this on three different computers with the same results in all cases. Currently, LV and the OPC server is the only software installed on any machine. The only other OPC server I have access to is the LV server, and it seems to work okay.
Thanks,
Wes
Attachments:
a793_appcompat.txt ‏133 KB
screen.JPG ‏105 KB
OPC I-O Server Diagnostic Information.txt ‏69 KB

Using Shared Variables and Initialize Front Panel Binding (to PSP)

Hi,
I use LV DSC RT 8.2.1
I have a Vacuum System That includes signals from - Pumps failure, Valves status, Vacuum gauge, start Pump ...
Each signal is read by a FieldPoint.
All the relevant FieldPoint Channels are read by the Server (a computer in the Ethernet Network) and published to the network in the form of Shared Variables.
I have a client VI that is reading the Shared Variables published by the Server using Front Panel Binding.
Problem :
Some of the Bindings are in the mode 'Write &Read' and that causes some initialization problems.
For example - Valve #1 is Open, and then a User start running the Client VI, (the Valve #1 Status mode is 'Write & Read")
if in the VI the status of Valve #1 is closed (before running it) then the Valve status is changing to Closed.
I want the Client VI to first read the Physical status of the instrument and then to change the Value if the User changes it.
But that's seems to be a problem when using Front Panel Binding... (is it?)
I know I can Deploy a lvlib in the Client Side and Item Bind to the Shared Variables or Use DataSocket.
(Is DataSocket is a Reliable method when connecting to Shared Variables? What are the disadvantages when using DataSocket?)
What is recommended by those of you that are experienced or by NI ?
Sincerely Yours,
Amitai Abramson.

Amitai Abramson,
Hello and thanks for using the NI Forums.
I'm glad that you've read the Using the LabVIEW Shared Variable Tutorial on our website. Check out these other resources:
Network Variable Technical Overview
Troubleshooting Network-Published Shared Variables
Why Do I See Unexpected Value Change Events for Shared Variables Using LabVIEW DSC?
All You Need to Know About Shared Variables
Creating a Value Change Event for Shared Variables
Alternative Method for Using Shared Variables Between Systems in LabVIEW 8.x
What Is The Difference Between Using Shared Variables And DataSocket VIs To Access OPC Tags?
The issue that you are seeing by having "Write & Read" bound items on both the server and client side is essentially a race condition, you don't know which one is being read/written at what time. To resolve this issue I would take a look at some of the documents below.
Using a Local, Global, or Shared Variable in Parallel Loops Can Cause Race Conditions
Using Local and Global Variables Carefully
Tutorial: Local Variable, Global Variable, and Race Conditions
Locking a Shared Resource or Variable in LabVIEW Using Semaphores
You mentioned not wanting to have two sets of shared variables (one on each side), but this is a great method to resovle this issue, that, or you can develope some sort of hand shaking to prevent these race conditions.
I would suggest that in the future when using these forums you try to ask only one question per thread and make it more concise. It's hard to tackle multiple questions and such broad questions as "I want to know all the ways that I can connect to Shared Variables, and I want to know the advantages and disadvantages." I suggest this because we want you to get your questions answered and more concise questions will result in quicker and better answers.
Message Edited by Ben S on 10-01-2009 06:05 PM
Ben Sisney
FlexRIO V&V Engineer
National Instruments

Dsc shared variable property are saved to library?

Hi,
I would like to be sure to know if the shared variable properties like "alarm level" and "description" are saved to the library directly?
If not, where? database?
Also can we not add table to the dsc ms sql express database? (the one for alarms and events)
Thanks
Patrick
Message Edited by paubine on 09-04-2009 08:23 AM

The properties of the shared variables like alarm and description do get saved to the library. As for your second questions about a table in ms sql, can you tell me more about this? Are you using the LabVIEW DSC VIs to do this, if so provide a screen shot or your code or a good description. Tell me exactly what is going wrong, what behavior you expect and what you are seeing.
Thanks,
Anna K.
National Instruments

Using a Meter control in LV Touch Panel, and using shared variables that are custom controls.

I Just started using LV touch Panel module with an NI TPC-2106.
I have two differenct problems:
1) I was planning on using the "Meter" control quite a bit. I can set up the meter exactly how I like on the host PC, but on the touch Panel computer it seems to ignore my adjustments, mainly the start and end of the scale - i.e. I would like control to run from 0 to 360 with 0 straight up, using the entire circle. However, on the Touch panel computer it always puts 0 at about 7 o'clock and 360 at about 5 o'clock. I have also tried adding markers to no avail.
2) I am communicating with a compact fieldpoint controller. I can creat a shared variable that is a simple double with no problems. However, I have some shared variables that use a custom control for the variable type - bascially a cluster with a couble doubles, a time stamp, and an enumeration. It lets me drag the shared variable into my diagram, but it seems to ignore it when I run it.

Ipshita_C,
- I am using LV 8.6.1f1and LV Touch Panel 8.6.1.
- I have attached a simplified VI that shows how I want to use the meter. Notice that the placement of the endpoitns does not work correctly on the touch panel, and that it ignores the arbitrary markers that I placed.
- I also have included an XY graph control that displays on the TPC with margins around the graph area that I removed from the graph control.
- For the shared variable, it appears to be an issue related to the touch panel, not fieldpoint. I found another thread in this forum that mentioned that clusters containing Enumerations do not work in shared variables on the touch panel. I changed the enumeration to an integer and it now works fine.
In general, there seem to be a disappointing number of limitations in the touch panel implementation. My biggest concern is that I have not found any documentation from NI that lists these limitations. I seem to have to try things out and see what works and what does not work. Can you point me to a comprehensive list of touch panel modules limitations?
Attachments:
test 2.vi ‏10 KB

Not able to access Network Shared Variable when deployed in PC

Initially, when we deploy a Network Published Shared Variable in PC and try to access the same (Read/Write) from RT, we get an error/warning "-1950679023". But when we access the same variable from the PC, it works fine. In the distributed system manager, we can see the variable getting deployed. Also the value changes in Distributed System Manager if we write a value from PC. The attached image "Shared variable Issue.png" will give more understanding of this issue.
The other way round it works fine i.e deploying in RT side and accessing from both RT and PC is working fine.
We also see that the network adapter settings is not loading properly in MAX, if at all we install any software in RT. With no software installed, it loads properly.
The following were the steps that we tried to solve the issue.
1.Flushing the entire NI software and Re- installing again
2.Formatting the RT(PXI).
3.Removing the EtherCAT Card and testing.
4.Checked the network properties of the RT network.
5.Checked the IP/Subnet/Gateway settings.
6.Checked Firewall Settings, If Shared Variable Engine is accessible.
Attachments:
Shared variable Issue.png ‏491 KB

First Root cause needs to be identified before any actions.
I would suggest first check if you can access the shared variable hosted in PC from RT using other ways like using SVE API (Logos and PS protocols, Datasocket etc..)
Check if antivirus or firewall is playing...
Check the same experiment with some other PC if you can.
You can also try creating another Shared Variable in RT and binding the same to the PC and try to access it...
Since you have did all the reinstallations already
Best Regards,
Vijay.

Can i fire Shared Variables' "Bad Status" alarm artificially?

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