LabVIEW and OPC server (Softwaretoolbox TopServer)

[Wim]

Hi,

I´m having problems accessing an OPC server in 2 parallel loops.

I have LabVIEW 7.1 (GOOP inheritence toolkit) and an opc-server (software toolbox TopServer)

I made an object oriented driver called ´The communicator´ (what´s in a name ). With it´s methods I can read and write items to S7 and S5 PLC´s.

A bit in detail:

When creating my communicator object; I create a number of virtual plc´s and a number of S5 subPLc´s if the VPLC is an S5.

S5 is a bit special: I use a DLL to communicate and I use the simulation driver of the OPC server to store my send and receive strings for S5

This driver is used in about 50 programs, each program initiates 15-30 Virtual PLC´s and accesses 50-150 TAGS on the server.

When i need to communicate with S5 and S7 in 1 program, I made 2 loops because s7 is much faster then S5. With my methods read S5 and Read S7 I acces S5 PLC´s in loop1(looprate 15s) and S7 PLC´s in loop2 (looprate 300msec)

Sometimes I see 2 clients popup in my OPC server and then all systems hold. CPU usage only 5% and memory only 300MB of 2Gb. I don´t get errors in the OPC subvi´s while writing or reading. When he systems holds, there are also no errors (I use the LabVIEW OPC subvi´s, the yellow functions)

I tried to split up S5 and S7 in seperate communicator objects to get a memory block for S7 communication and one for S5. Result is that I still have 2 OPC clients.

When I put everything in 1 loop (so S7 comm. is quite slow) I only have 1 client and no crashes.

I think LabVIEW makes an extra client (1 for each loop) and that makes my program crash. is there a way to have only one LabVIEW client and use parallel loops ?

At creation of the object I open all OPC connections and store the ref´s in an array. In case of error I close and reopen. At shutdown I close the reference, but i don´t want to shutdown because it is a visualisation and steering of an industrial process that runs continiously.

I hope my story and question is clear to you. If you need more info to be able to give me advice please ask, I will check the topic frequently.

Thanks in advance.

Regards,

Wim

[Wim]

Hi all,

I have found a bug in my driver, not related to OPC crashes but it speeds up my reading loop so I no longer need to split up S5 and S7 reading. Looptime is acceptable to put them in one loop.

So problem solved ...

Greetings.

[Arun Luthra]

Hi Wim,

I am doing same what you are doing i am using the plc with OPC server but problem is i had 150 tags had having the 3 different VIs which is share 50 tags each at the back three process are running for each VIs when i run on my pc it is communication fine but when i run on my client PC in b/w the communication got failed i donot know why will you please help me to solve my problem i had also post my thread in ni.http://forums.ni.com/ni/board/message?board.id=170&thread.id=430655

[Wim]

Hi,

I've read that you are using shared variables. I've never used this so can't help you with this one.

I used the Datasocket VI's ( the yellow datasocket VI's) to open a reference, then Read/Write to the datasocket TAG and close the ref when closing the program or when I detect an error.

Maybe you can try these VI's.

Good Luck,

Wim