Mitsubishi Electric L02SCPU User's Manual And Reference page 102

(e) Precautions
The following describes precautions for the service processing setting.
• In the service processing, the processing for request data from each receiving port (each intelligent function
module, USB, RS-232, and built-in Ethernet) is performed one by one. If several requests are received one
after another from the same receiving port, the service processing may not be performed in the same scan
even if the service processing time is left. For this reason, in communications with multiple peripherals via
the built-in Ethernet port, response times to each peripheral may not be improved, regardless of the service
processing time setting. In this case, divide connections of peripherals into the Ethernet module and the
built-in Ethernet of the CPU module to improve the response time.
• Since the processing for a request including accesses to files takes time, responding to the request
necessarily takes time. The processing for request data is performed one by one in the service processing,
and therefore responses to succeeding request data delays when the CPU module receives a request
including accesses to files. For this reason, set a longer timeout time for peripherals when using a system
that regularly send these requests.
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