Mitsubishi Electric QJ71GF11-T2 User Manual page 101

Item
Set "Link Scan Mode Setting", "Loopback Function Setting", "Block
Data Assurance per Station", and "Operation Setting for Returning".
(1) Link Scan Mode Setting
Item
Asynchronous
Constant Scan
button
Synchronous
*1
(2) Loopback Function Setting
Select whether to use the loopback function. (
Section 8.7) To configure a network in ring topology, select the
checkbox.
(3) Block Data Assurance per Station
Select whether to assure data integrity on a station basis in link
refresh between the CPU module and the master/local module.
( Page 134, Section 8.1.5)
(4) Operation Setting for Returning
When using the submaster function, select the operation of the
master station after it returns from the disconnected status. This
parameter can be set only when "Sub-Master Station" has been
selected in "Station Type".
Description
Description
Link scan is performed asynchronously with the
sequence scan of the CPU module. Select this item to
shorten input transmission delay time when sequence
scan takes much time than link scan. Note that output
transmission delay time will become longer.
Cyclic transmission is performed punctually. Link scan
time will be the constant link scan time set in this
setting.
However, when the actual link scan time is longer than
the specified link scan time, cyclic transmission is
performed by actual link scan time.
While constant link scan is used to keep link scan time
constant, the transmission delay time is not kept
constant by this function. To keep transmission delay
time constant, select "Synchronous".
Link scan is performed synchronously with the
sequence scan of the CPU module. Select this item in
the following cases:
To shorten output transmission delay time (Note that
when sequence scan takes much time than link scan,
input transmission delay time will become longer.)
To keep transmission delay time constant
When a link scan is synchronized with a sequence
scan, modify the program so that the sequence scan
time of the CPU module will be within 200ms. If
200ms is exceeded, slave stations may be
disconnected.
The sequence scan must be constant as well.
Set a time value under "Constant Scanning" in
the "PLC RAS" tab of the PLC parameter
window.
CHAPTER 7 PARAMETER SETTING
Setting range
• Link Scan Mode Setting:
Asynchronous, Synchronous
(Default: Asynchronous)
• Loopback Function Setting:
Selected (Use)/not selected
(Default: Not selected)
• Block Data Assurance per Station:
Selected (Assure Block Data)/not
selected
(Default: Selected (Assure Block
Data))
• Operation Setting for Returning:
Return as Master Station, Return as
*1
Sub-Master Station
(Default: Return as Master Station)
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