Mitsubishi Electric MELSEC-QS Series Safety Application Manual page 34

4
PRECAUTIONS FOR USE OF SAFETY
PROGRAMMABLE CONTROLLER
Input
C
Emergency stop switch
Figure 4.2 Example when one QS0J65BTS2-8D and one QS0J65BTS2-4T are used
4
4.1 Precautions for Designing Safety Application
- 4
(b) When using one QS0J65BTS2-8D and one QS0J65BTS2-4T
PFD = (PFD of A) + (PFD of B) + (PFD of C) + (PFD of D)
= (4.10 10 + 8.75
-5
= (1.62 10 ) + (PFD of C) + (PFD of D)
-4
PFH = (PFH of A) + (PFH of B) + (PFH of C) + (PFH of D)
= (9.20 10
-10
= (6.26 10 -9 ) + (PFH of C) + (PFH of D)
A
10 ) + (1.68 10
-5 -5
+ 3.85 10 ) + (7.46 10
-9 -10
B
+ 1.68 10 ) + (PFD of C) + (PFD of D)
-5
+ 7.46 10 ) + (PFH of C) + (PFH of D)
-10
Output
D
Safety relay