CTI 2572-A, Installation And Operation Manual

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CTI 2572-A Installation and Operation Guide V1.3 67
8.5. Performance Problems
Symptom Probable Cause Corrective Action
Performance is sub-standard at
all times. The module is not getting enough
access to the PLC. Ensure that the number of task
codes per scan is set as high as
possible (preferably eight).
Ensure the module is installed in a
local base. Throughput will be
degraded in a remote base.
The network traffic is excessive. Observe the Collision indicator. If
this flashes frequently, the network
is busy. Use the module diagnostic
capability to analyze the Ethernet
traffic measurements. Use a
network analyzer to capture
network traffic.
If you observe a problem you must
correct the problem by reducing the
traffic load, or segmenting the
network using Ethernet
switches/routers.
Network broadcast traffic is excessive.
Broadcast traffic consumes processor
resources for every station on the
network. Use the module diagnostic facility
to capture the count of broadcast
traffic. Use a network analysis tool
to analyze the broadcast traffic on
the network. If a problem is found
you must reduce the broadcast
traffic by reconfiguring the
offending station(s), removing the
station(s), or separating them from
the local area network via a router.
NOTE: Using a simple switch will
not reduce the broadcast traffic on
an Ethernet segment since the
switch sends broadcasts to every
port.
The requested data is highly fragmented
in the PLC, requiring many random
access transactions. Copy fragmented data to/from
contiguous V memory. This allows
efficient block reads and writes.
You have many clients accessing a
single 2572-A causing an excessive
transaction load. Reduce the client poll rate or
amount of data requested. Split the
load among multiple modules.
You are making heavy use of the Client
function in combination with the Server
function. Don’t trigger the Client command
more often than required. Split the
load among multiple modules.
Module is located in a remote base. A
Special Function module such as the
2572-A is considerably slower in a
remote base and may increase scan
time considerably. Place the 2572-A module in a local
base.
Performance is substandard at
times, acceptable at other Something is interfering with the
Ethernet network. Observe the Collision indicator for
signs of excessive collisions. Use
the module diagnostic facility to