Dear Shea, Many thanks for your answer. I am running Labview 6.i (version 6.0) so it is likely that my problem is caused by the reason you are describing. However, I found on the NI website some discussion on the compatibility of DataSocket with OPC servers, where it was mentioned that the OPC examples shipped with Labview 6 are actually those present in earlier versions (so I assume these are the primitives from 5.1 you are referring to, is this assumption correct ?). I have used one of these examples (NI Demo OPC Client.vi) to connect to my third party server where I canged the server and item name to my third party server characteristics. This runs well but also here I manage to crash Labview completely when the Third Party Server crashes. Given this effect, I have not yet recoded my Labview client to use these primitives which I assume then to be located in Labview 6\vi.lib\Platform\dataskt.llb.
Reading the NI website I might have found a reason which makes my Third Party crashing anyway, which could be due to Labview (though right now I am already blaiming my third party software supplier). As I use the 6.i Datasocket primitives, it says that for every read instruction in my client program it opens, reads and closes the connection. This repeatedly opening and closing may overload the OPC server (which indeed crashes during my tests while giving a message that it has found a problem to wrtie something to memory). I am not sure yet, but I am now testing my Labview client at a higher speed which generates more data reads to see if my third party server crashes now more frequently (up to now it crashed every couple of hours while I am reading about 60 data items every second so I am now testing at a 10 times higher speed). Any further suggestions, Martien "Shea C" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] Hello Martien, Thank you for your inquiry regarding LabVIEW DataSocket. I understand LabVIEW crashes when the third party OPC server generates an error. The DataSocket Read.vi in LabVIEW 6.02 does not correctly handle shutdown of the Lookout Protocol Driver (LPD) OPC Server. The DataSocket Read VI (with wait for change = false) does not indicate any errors if the Lookout Protocol Drivers OPC Server crashes or is manually shutdown. Instead, it continues to read the last good value from a previous call to DataSocket Read.vi. This causes LabVIEW to crash. If you are using LabVIEW 6.02 one possible solution is use a DataSocket Read.vi from LabVIEW 5.1 VI primitives. However, this problem shouldn't occur on LabVIEW 7.0. I hope these resources help. Let me know if I can further assist you. Shea C. Applications Engineering
