8 RUNNING A PROGRAM
8.2 Scan Time
89
8
Operations enabled by setting details
Operations enabled by setting details of the device/label access service processing setting are as follows.
*1 This term indicates how long the scan time will be extended at its maximum due to the device/label access service processing.
*2 This term indicates how much the scan time will be varied due to the device/label access service processing.
*3 This term indicates how long the response time will take after a request for the device/label access service processing is received from
an engineering tool or the like.
*4 This term indicates how much the response time will be varied depending on the contents of requests for the device/label access service
processing from engineering tools or the like.
*5 When this function is enabled, monitoring is performed between execution of programs, and therefore values of ongoing operation may
be read out. ( Page 90 When "Execute END Processing between Programs" is enabled)
For what operation is enabled by setting each item, refer to the following.
Page 737 Operation details
Item Scan performance Device/label access
service process
performance
Inter-
program
monitoring
*5
Application
Increase
*1
Stability
*2
Response
time
*3
Stability
*4
Execute the
Process as Scan
Time Proceeds
Medium Medium Medium Medium None This setting is useful to execute the device/label access service
processing in a way commensurate with the system size. It allows
the system to be designed without considering the device/label
access service processing time because it is determined as a
function of the scan time.
Multiple requests are processed until the specified ratio is
exceeded. If exceeded, the remaining requests are processed in
the END processing of the next scan. When no request data is
received in the current scan, the scan time is shortened by the
specified ratio as the CPU module proceeds to the next scan
without waiting for requests.
Set Processing
Time
Medium High Medium High None This setting is useful to give priority to the device/label access
service processing. It allows for stable communication because
the CPU module can always process a constant amount of the
device/label access service processing without affecting the scan
time.
Multiple requests are processed until the specified processing time
is exceeded. If exceeded, the remaining requests are processed in
the END processing of the next scan. When no request data is
received in the current scan, the scan time is shortened by the
specified processing time as the CPU module proceeds to the next
scan without waiting for requests.
Set Processing
Counts
Large Low Medium High None This setting is useful to stably execute the device/label access
service processing in a system where requests come from multiple
peripherals. It provides stable communication in a system where
multiple peripherals exist because the CPU module can execute
the device/label access service processing based on the number
of request sources.
Multiple requests are processed until the specified number of
executions of the service processing is reached. When no request
data is received in the current scan, the CPU module proceeds to
the next scan without waiting for requests.
Execute END
Processing
between
Programs
Large Medium Quick High Yes This setting is useful to give priority to the device/label access
service processing in a system with a large number of programs. It
improves the communication response as it enables the device/
label access service processing to be executed multiple times
during a single scan.
When no request data is received between program executions
and/or during the END processing, the CPU module proceeds to
the next program or scan without waiting for requests.
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