Set/Reset Operations - Siemens SIMATIC S5 Manual

S5-115F Manual
3.1.2

Set/Reset Operations

Set/reset operations store the result of the logic operation (RLO) generated in the processor. The
stored RLO represents the signal state of the addressed operand. Storage can be dynamic (assign-
ment) or static (set and reset). Table 3-2 provides an overview of the set/reset operations.
Examples follow the table.
Operation Operand
S
R
=
ID
I
Q
F
* FW 0 is reserved for the logical program counter.
FW 2 to FW 198 (F 2.0 to F 199.7) permissible for the user program.
FW 200 to FW 254 (F 200.0 to F 255.7) only permissible as scratch flags within a block. Scratch flags must be defined, set
or reset at the start of a block run and also after conditional and unconditional block calls. In this way, data exchange
with other blocks is avoided.
EWA 4NEB 811 6149-02
Table 3-2. Overview of Set/Reset Operations
Set
The first time the program is scanned with RLO = "1", signal state
"1" is assigned to the addressed operand.
An RLO change does not affect this status.
Reset
The first time the program is scanned with RLO = "1", signal state
"0" is assigned to the addressed operand.
An RLO change does not affect this status.
Assign
Every time the program is scanned, the current RLO is assigned to
the addressed operand.
Parameter CPU 942F
0.0 to 127.7
0.0 to 125.7
0.0 to 255.7
Meaning
*
STEP 5 Operations
3-7