Fail-Safe Blocks
Fail-Safe Systems
8-100
A5E00085588-03
Error Information in Diagnostic Buffer
Error Code (W#16#...)
Description
0x75D9
Invalid REAL number
0x75DA
Error in the safety data format (error due to online modification of the
Safety Program or internal CPU fault)
8.9 Flip-Flop
Blocks
Block
Description
F_RS_FF
RS flipflop, resetting dominant
F_SR_FF
SR flipflop, setting dominant
8.9.1 F_RS_FF
Function
The block executes the function of an RS flipflop (resetting dominant).
The RS flipflop is reset if the signal state at the input R = 1 and at the input S =
0. The flipflop is set if the input R = 0 and the input S = 1. If the result of the logic
operation is 1 at both inputs, the flipflop is reset.
Truth Table
R
S
QN
QNn
0
0
Qn-1
QNn-1
0
1
1
0
1
0
0
1
1
1
0
1
I/Os
Name
Data Type
Explanation
Default
Inputs:
R
F_BOOL
Reset
0
S
F_BOOL
Set
0
Outputs:
Q
F_BOOL
Output
0
QN
F_BOOL
Negating output
1
Summary of Contents for SIMATIC S7 F
Page 8: ...Important Information Fail Safe Systems viii A5E00085588 03 ...
Page 16: ...Contents Fail Safe Systems xvi A5E00085588 03 ...
Page 38: ...Product Overview Fail Safe Systems 1 22 A5E00085588 03 ...
Page 56: ...Getting Started Fail Safe Systems 2 18 A5E00085588 03 ...
Page 70: ...Safety Mechanisms Fail Safe Systems 3 14 A5E00085588 03 ...
Page 115: ...Programming Fail Safe Systems A5E00085588 03 5 33 Examples Receive Block Send Block ...
Page 154: ...Programming Fail Safe Systems 5 72 A5E00085588 03 ...
Page 166: ...Operation and Maintenance Fail Safe Systems 6 6 A5E00085588 03 ...
Page 332: ...Fail Safe Blocks Fail Safe Systems 8 144 A5E00085588 03 ...
Page 344: ...References Fail Safe Systems B 2 A5E00085558 03 ...
Page 350: ...Glossary Fail Safe Systems Glossary 6 A5E00085588 03 ...