Set And Reset Dominant Bistable Instructions - Siemens SIMATIC S7-200 System Manual

Set and Reset Dominant Bistable Instructions

The Set Dominant Bistable is a latch where the set
dominates. If the set (S1) and reset (R) signals are both
true, the output (OUT) is true.
The Reset Dominant Bistable is a latch where the reset
dominates. If the set (S) and reset (R1) signals are both
true, the output (OUT) is false.
The Bit parameter specifies the Boolean parameter that is
set or reset. The optional output reflects the signal state of
the Bit parameter.
Table 6-7 shows the truth tables for the sample program.
Table 6-6 Valid Operands for the Set Dominant Bistable and Reset Dominant Bistable
Instructions
Inputs/Outputs
S1, R
S, R1, OUT
Bit
Example: Set and Reset Dominant Bistable Instructions
Table 6-7 Truth Table for the Set and Reset Dominant Bistable Instructions
Instruction
Set Dominant Bistable instruction
(SR) (SR)
Instruction
Reset Dominant Bistable instruction
(RS) (RS)
Data Types Operands
BOOL I, Q, V, M, SM, S, T, C, Power Flow
BOOL I, Q, V, M, SM, S, T, C, L, Power Flow
BOOL I, Q, V, M, S
Timing Diagram
Set I0.0
Reset I0.1
SR Q0.0
RS Q0.1
S1
0
0
1
1
S
0
0
1
1
S7-200 Instruction Set
R Out (Bit)
0 Previous state
1 0
0 1
1 1
R1 Out (Bit)
0 Previous state
1 0
0 1
1 0
Chapter 6
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