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I would like the opinions of those on the list regarding the following OPC server issue. As far as I understand it, if an OPC client is connected to an OPC server and that client crashes or isn't shut down properly, the connection remains open in the OPC server. You can imagine tens of clients connected to one or more OPC servers crashing over time. Wouldn't these open connections load down the OPC server and eventually overflow the buffer? The OPC server stability becomes dependent on the clients which may or may not be stable.
In addition, OPC servers cannot be properly shut down if clients are connected. Just one crashed client and the OPC server doesn't let you shut it down properly. Or maybe the OPC server needs to be shut down and there is a client somewhere on the network that is still connected.
I think there are some serious robustness & fault tolerance issues that need to be addressed with OPC before I feel comfortable using it for industrial automation. One problem I see is that OPC is based on a Micrsoft spec (i.e., COM & DCOM) and is therefore dependent on Microsoft and their specialty is not in industrial automation. That's what scares me. Was the COM & DCOM spec written for use in industrial automation or was it created for use in office and home applications?
I welcome your comments.
David Bergeron, P.E.
TECO
504-833-6381
www.thompson-equipment.com
In addition, OPC servers cannot be properly shut down if clients are connected. Just one crashed client and the OPC server doesn't let you shut it down properly. Or maybe the OPC server needs to be shut down and there is a client somewhere on the network that is still connected.
I think there are some serious robustness & fault tolerance issues that need to be addressed with OPC before I feel comfortable using it for industrial automation. One problem I see is that OPC is based on a Micrsoft spec (i.e., COM & DCOM) and is therefore dependent on Microsoft and their specialty is not in industrial automation. That's what scares me. Was the COM & DCOM spec written for use in industrial automation or was it created for use in office and home applications?
I welcome your comments.
David Bergeron, P.E.
TECO
504-833-6381
www.thompson-equipment.com