Bit Test Operations - Siemens SIMATIC S5 Manual

STEP 5 Operations
3.2.3

Bit Test Operations

Bit test operations scan digital operands bit by bit and affect them. Bit test operations must always
be at the beginning of a logic operation. Table 3-12 provides an overview of these operations.
Operation Operand
TB
TBN
SU
RU
ID
T
C
D
RS
1
1 RS applies only to TB and TBN.
Table 3-13 shows how the RLO is formed during the bit test operations "TB" and "TBN". An
example for applying the bit operations follows the table.
Table 3-13. Effect of "TB" and "TBN" on the RLO
Operation
Signal state of the bit in
the operation indicated
Result of logic operation
3-44
Table 3-12. Overview of Bit Test Operations
Test a bit for signal state "1".
A single bit is scanned regardless of the RLO. The RLO is affected
according to the bit's signal state ( Table 3-13).
Test a bit for signal state "0".
A single bit is scanned regardless of the RLO. The RLO is affected
according to the bit's signal state ( Table 3-13).
Set a bit unconditionally.
The addressed bit is set to "1" regardless of the RLO.
The RLO is not affected.
Reset a bit unconditionally.
The addressed bit is set to "0" regardless of the RLO.
The RLO is not affected.
Parameter
0 to 127.15
0 to 127.15
0 to 255.15
0 to 255.15
TB
0
0
Meaning
TBN
1 0 1
1 1 0
S5-115F Manual
EWA 4NEB 811 6149-02