Wrong quality status of shared variable connected to OPC Client

[Kacper]

Hello I have serious problem with OPC Client and shared variable satus. I use NI OPC Server (aka KEPServerEX) and OPC Client in LV DSC 8.5. OPC Quick Client reports Status:Bad but status of shared variable connected to OPC Client is OK. If I turn device on, OPC Quick Client return status Good. I used DataSocket to read status of OPC tag and it's 0 (for bad status) or 192 (for status OK). Status of shared variable doesn't change regardless real status of communication. There is thread "How to read the quality of OPC tag in LV8.0 DSC" with identical problem and there is bug report number 3VUE5KTM but I cannot find any other information. (Answer "we know this problem and we work on it - it will be solved in next version of labview" is NOT ACCEPTABLE; I think that NI politics of fixing bugs in next versions instead of service packs is good topic for discussion.) best regards Miroslaw Kasperek Introl Sp. z o.o. Poland

[Nitin_T]

Hi Kacper,

I had a couple of questions.

1) What device are you turning on. Does this device provide the values for the shared variables.

2) Are there shared variables hosted on this device.

3) You also mentioned "the status of shared variable doesn't change regardless of the real status of communication". Which specific status information was not being updated. Or were there no updates to the status at all.

Thank you for bringing this to our attention.

[Kacper]

HI

1. From reply of Lorenz03Tx (thread "How to read the quality of OPC tag in LV8.0 DSC?"):

"Your issue as I understand it is as follows:

1) You create an OPC Client I/O Server and connect to an OPC Server.
2) You bind a Variable to an Item under the OPC Client I/O Server
3) You are able to read data, but you are not getting an error out from the Variable node on the block diagram when the quality goes bad.
[...]
There is an issue where the OPC Client appears to be dropping the quality in some cases. Thank you for pointing this out, I filed a bug report (# 3VUE5KTM) and hopefully we will have this fixed in the next version of LabVIEW."

2. Look at the attachment in first post (example is worth more then 100 words (or even more 🙂 ) ). You should load test.opf in NI OPC Server first. Then try, in Device properties, to turn on and off "Simulate device".

I hope this will help

best regards
Miroslaw Kasperek
Introl Sp. z o.o. Poland

[Nitin_T]

Hi Kacper,

I am trying to get more information regarding the CAR# 3VUE5KTM. Will keep you posted as to what I find.

As far as finding out the Quality, (other than using datasockets), have you tried using alarms for bad status. Events can be called based on the alarms configured with the Shared Variables. This will help in monitoring the quality. Hope this helps.

[Kacper]

Hi

I cannot use neither datasocket nor alarms.
1. When I try to connect to NI OPC Server (via DataSocket Select URL.vi) I get error:

"The connection to the server failed!:
error code - 0x80004002
No such interface supported
An OPC interface could not be found
Ensure that the latest opcproxy.dll is installed and that it has been registered"

Other OPC servers work fine (including KEPServerEx !).

2. Alarm (from bad quality) doesn't work.

I feal like a beta tester :(.

Miroslaw Kasperek
Introl, Poland

[MeghanK]

I've included a link to a KnowledgeBase article which discusses the error you are receiving.  Manually registering the opcproxy.dll might fix this.  Let me know if it works, thanks!

[broken link removed]

[Kacper]

Hi

Yes I have read this article before and of course it doesn't help me at all - after unregistering opcproxy.dll all opc servers return error 0x80004002. After registering all servers work except NI OPC Server.

Problem with NI OPC Server it's not so important (NI OPC could be replace with identical but working KEPServerEx).
The most important is problem with quality status.

regards
Miroslaw Kasperek
Introl, Poland

[Nitin_T]

Hi Kacper,

This was reported to R&D (# 4G47EU5D) for further investigation. This meaning the issue with the quality going bad and the variable not indicating it. I'll get back to you as soon as I get more information. Thank you.