1 RUNNING A PROGRAM
1.2 Scan Time
45
1
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 46 When "Execute END Processing between Programs" is enabled)
For what operation is enabled by setting each item, refer to the following.
Page 938 Operation details
Precautions
This section describes the precautions on the device/label access service processing setting.
■Functions that may prolong the scan time
For the following functions, the scan time may become longer than the specified time during processing even when this
setting is applied.
• Online change
• Device/buffer memory batch monitor
• Data logging function
• File register write or read
*1
*1 The scan time becomes longer when the size of data to write or read is large
■When constant scan is set
The CPU module always processes one request during the END processing, and processes the remaining requests during
the wait time for the next constant scan. Set constant scan setting time considering the time required for the device/label
access service processing to execute.
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.
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.
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.
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
response performance as it enables the device/
label access service processing to be executed
multiple times during a single scan.
To Next Page
Loading...
