OPC Connection faliure/status using LabView & Protool

[robertmodic]

Hi there,

we are integrating NI Vision solution into Siemens Step7/Protool automation environment. Two CVS modules perform visual inspection and communicate via Ethernet with Siemens Protool vizualization/GUI application running on Windows XP based PC. Protool is serving as OPC 2.0 compliat server and LabView "helper" application on PC is mirroring OPC data to and from NI PSP (Shared variable) domain which NI CVS-es use to communicate. All works well until we shut down and/or restart Protool (and thus the OPC service along with it).
Helper application fails to acknowledge any Connection Status change (as its status remains: Connected) if/when OPC is turned off ... furthermore once the Protool OPC is up and running again the values in LabView OPC bound items within helper app. cease to be updated although their Connection Status Property is shown as: Connected throughout ...

Has anyone had a similar problem? What could be the cause/solution to the behavior described?

Thanks in advance,

Robert

[Torba]

Hello Robert,

Thank you for contacting National Instruments.  It sounds like you are using Datasocket to communicate between CVS modules and a GUI application using a Siemens protocol.  There is an OPC server that is responsible for translating OPC data to PSP data so that the CVS modules can interpret it.  Is this correct?  Is the "helper" application responsible for this translation?

When the server is power cycled, is there any evidence that the CVS systems are still running their applications like normal?  Do you have connection flags in the CVS code that will signal a broken connection, and if so do they show a "connected" status?

Regards,

Mike T

National Instruments

[robertmodic]

Hi Mike,

LabView "helper" app. is residing on Win PC and has controls that are data-bound to ProTool OPC via datasocket. The PC hosts shared variables that CVS-es use to communicate to PC. helper app. is transfering data between ProTool OPC and NI PSP network as necessary. If OPC is "power cycled" the "datasocket LED" of OPC DataBound controls remains green as nothing happened! If we use DataSocket (DS) pallete to programatically open DS conneciton to an OPC item, connection is rejected if OPC is not running, but once connected the "connection:status" property wont change if we shutdown the OPC!

Why is this happening? Is there a manner to detect the "running" status op OPC? Is there a more elegant way to bring OPC and NI PSP network together that would bypass the need for data pooling? Would the functionality of DSC help, like "register for events notification" function?

We would sure could use a quick soultion to this ...

Thx and regards, Robert

[Christopher W]

I was able to replicate the green LED staying green with a power cycle of the OPC.  I would use the quality output from the DataSocket Read.  If the quality is 192, you have good data.  When I power cycled, the quality went from 192 to 24.

The DSC module would be a much more elegant way to achieve this.  It easily links up OPC items with shared variables so you would not have to use data socket.

Christopher W.