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

S7-200 Programmable Controller 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
6
Inputs/Outputs
S1, R
S, R1, OUT
Bit
Example: Set and Reset Dominant Bistable Instructions
Table 6-7
Instruction
Set Dominant Bistable instruction (SR)
Instruction
Reset Dominant Bistable instruction (RS)
72
Valid Operands for the Set Dominant Bistable and Reset Dominant Bistable Instructions
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
Reset I0.1
SR
RS
Truth Table for the Set and Reset Dominant Bistable Instructions
I0.0
Q0.0
Q0.1
S1 R
0 0
0 1
1 0
1 1
S R1
0 0
0 1
1 0
1 1
Out (Bit)
Previous state
0
1
1
Out (Bit)
Previous state
0
1
0