I am using Lookout 6.0.2 on a new Win XP desktop. The Lookout OPC client object is used for communications via Rockwell Software RSLinx's (Professional Rev 2.43.01.23) OPC server to ControlLogix PLC's over ethernet. In other words, the Lookout communicates with RSLinx by OPC, and the RSLinx communicates with PLC's by ControlNet.
We have 3 Lookout processes, one which is the "server" process, and contains the OPC Client object. The other 2 process files are "client" processes, and reference the OPC Client object by symbolic link.
We have many Lookout switches in the "client" processes, that are remoted to a tag in the ControlLogix PLC using symbolic link. A typical link for a remoted switch is:
..\..\[Link_to_Drivers]\OPCclient1.PLC_12.Online.SWITCH_TAGNAME
OR IF USING ABSOLUTE REFERENCE: \\ComputerName\ProcessName\[Link_to_Drivers]\OPCclient1.PLC_12.Online.SWITCH_TAGNAME
In this way, the Lookout switch object has a read/write link.
The problem is this: Periodically the write link will stop working. When this happens, all the Lookout switches and even the Lookout pots will lose ability to write to PLC, but the read links are still working. We can read the data and the switch positions, but the changing setpoints with the pots and operating equipment with the switches is then impossible. This "lock up" can be fixed by closing down all the Lookout processes (but not Lookout), and then restarting the Lookout processes.
This problem is intermittant and not repeatable. Does anyone have idea how to troubleshoot this problem, or have an way to isolate and fix this problem?
