OPC90 Server
Note that a network failure will cause the backup OPC90 server to command its
CIU online if configuration shadowing cannot communicate with the other OPC90
server. By design, this will occur between one and two minutes after the network
failure occurs. If the other CIU is still online, the backup being commanded
online will fault with a code indicating a same address was detected. Therefore,
don’t conclude that CIU red light conditions are always the result of faulty
network interruptions are not occurring.
dition does occur, after configuration
.3.9.2 OPC Client Access of Redundant Servers
ith redundant OPC90 Servers, the OPC lient must implement logic to decide
the
alue of this tag is zero, OPC90 communication with the CIU is valid. The
second is to monitor OPC90 server status. OPC clients utilize the OPC
GetStatus method to read a server’s status. This function returns several data
items regarding the status of the server. One of those items is the server state
which can be used to determine if the server is running or faulted due to
communication with all the CIU(s) being bad. It returns 1 when running and CIU
communication is good otherwise it can be setup to return 2 (fault) when CIU
communication is bad. Also, optionally the GetStatus return code can be
configured to return RPC_E_FAULT (2,147,549,444) when communication with
all CIU(s) is bad.
The settings for the GetStatus server state and return code are configured using
the Edit | Error Logging dialog.
5.3.10 Error Detection
The error detection logging feature is useful when trying to isolate data exchange
problems with OPC client software. The logs are text files viewable by notepad
and can be found in the C:\Program Files\OPC90 Server\Log directory. Select
“Edit->Error Logs” to configuration the error log options. When this menu item is
elected the following dialog is displayed:
hardware. Make sure
If configuration shadowing is turned off for systems setup with same address
CIUs while the standby OPC90 is communicating with the CIU, it will command
its CIU online resulting in the aforementioned CIU red light condition to occur.
The only way to avoid this from happening is to disconnect all OPC clients from
OPC90 and command it out of runtime mode of operation before turning off
onfiguration shadowing. If the red light con
c
shadowing is re-enabled, just physically reset the red lit CIU to put it back into
operation.
5
W
c
which server to access the data from. A common method is to base the decision
on two OPC90 data points.
he first is the state of the OPC90 Device block ALL_STATUS tag. When
T
v
s
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