Mitsubishi Electric Melsec-QS Series Safety Application Manual page 77

APPENDIX
(a) Link scan time (LS)
The following shows the formula for the CC-Link Safety link scan time (LS)[ s].
LS = BT
BT: Constant
Transmission speed
NI : Final station No. in A and B (Higher value between A and B)
NW : Final station No. in B
A : Final station No. of standard remote I/O stations
B : Final station No. of safety remote I/O stations and remote device stations
Final station No. 1 to 8
NI,NW 8
N : Number of connected modules (excluding reserved stations)
ni : a + b (excluding reserved stations)
a : Total number of occupied standard remote I/O stations
b : Total number of occupied safety remote I/O stations and remote device
nw : b (excluding reserved stations)
TR : Constant
ST : Constant
RT : Retry processing time (only when there is a faulty station)
+
: Return processing time for 1
: Return processing time for 2
F : Return to system processing time (only when communication faulty station
(27+(NI 4.8) + (NW
+ ST + RT+ F [ s] LS calculation formula
156kbps
BT 51.2
(Including the number of occupied stations and excluding reserved stations,
in multiples of 8.)
(Including the number of occupied stations and excluding reserved stations,
in multiples of 8.)
(When not connecting standard remote station, put 0 to A.)
9 to 16 17 to 24 25 to 32
16 24 32
stations
Constant Numeric value
TR 38.4
(for asynchronous mode only. For synchronous mode, ST = 0. )
(1) or 2), whichever is greater. Ignore 2) when B = 0.)
1) 800 + (A 15)
2) 900 + (B 50)
(Number of detected faulty stations - 1)
BT ((200 + R) Set number of retries + 200)
R: 51.6+(NI 4.8)+(NW
BT ((200 + P) Set number of retries + 200)
P: 10.8
exists)
BT 218 Number of automatic return modules
Appendix.1 Calculation Method of Safety Response Time
9.6) + (N 30) + (ni 4.8) + (nw
625kbps 2.5Mbps 5Mbps
12.8 3.2 1.6
33 to 40 41 to 48 49 to 56
40 48 56
st
module
9.6)
nd
or sebsequent module
1
9.6)+ TR)
2
10Mbps
0.8
3
4
57 to 64
64
5
App
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