Reduction Of The Link Scan Time; Control Station Shift Time - Mitsubishi Electric Melsec QJ71LP21 Reference Manual

3 SPECIFICATIONS

3.3.4 Reduction of the link scan time

3.3.5 Control station shift time

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The amount of link refresh and link scan data (LB/LW) per END processing can be
reduced by assigning the data in the link devices (LB/LW) for normal cyclic
transmission, which does not require high-speed transmission, to the extension area
(2000 to 3FFF ), and transmit it by the low-speed cyclic transmission.
H H
(High Performance model QCPU, Process CPU, Redundant CPU, and Universal
model QCPU)
Q25HCPU
Link refresh
1M 1
P
1N 2
S
1N 3
S
1FFF
Low-speed link refresh
The time required to shift the control station status (control station shift time) can be
calculated from the following expression:
[Control station shift time (Csw)]
Csw=( 12) + (
a b
: Number of normal stations after control station cut-off
a
: Number of abnormal stations after control station cut-off
b
: Set value of constant link scan (Refer to Section 5.4.)
c
Common
parameters
0
1M 1
P
1N 2
S
1N 3
S
2000
1M 1
P
1N 2
S
1N 3
S
3FFF
11) + ( 3) + 450 [ms]
c
MELSEC-Q
Normal cyclic transmission range
Low-speed cyclic transmission range
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