Using the Server Monitor
Server Statistics
This panel shows the current server statistics. This is useful for
viewing the server status in real-time.
Server StatisticsView
The following statistics are available:
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Server State: Current server state(running, stopped).
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Server Time: Current server time (important for
timestamps).
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Groups: Number of OPC groups in the server.
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Clients Connected: Number of clients connected to the
server.
-
Scan Status: Current state of server data acquisition
core(active, inactive).
-
Active Devices: Number of devices under real-time
monitoring.
-
Device Items: Number of device items under real-time
monitoring.
-
Server Status: Current status of server (normal or scan
overlap).
If the server status indicates scan overlaps, it means that your
current configuration is not optimized for scanning the configured
devices. Scan overlaps happen when the server time becomes
insufficient to maintain the configured device refresh rate. The
main cause for this problem is a high response time from some SNMP
devices, causing the server to wait too much time for a device
response. Here are some tips for improving performance:
-
Disable the scan of unused devices. Make sure that the server
is scanning only devices which will be used by your OPC
clients.
-
Remove all unused items that are published. Make sure that you
are publishing only items that will be used by your OPC
clients.
-
On congested networks, the SNMP packet information may suffer
high delays to reach the server. Make sure that the SNMP server
is connected to the managed devices through good links.
-
Some devices does not support reading too many OIDs in the same
SNMP call. If you are reading bad values from such devices, try
to reduce the number of Group OIDs for them.
-
Some devices are really slow to process SNMP data. In these
cases you will have to reduce the number of published items or
reduce the refresh rate (increase the time) in order to get
better scan times.
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