Evaluating Conditions Using And, Or And Exclusive Or - Siemens CPU 412-1 Instruction Manual

Evaluating Conditions Using AND, OR and EXCLUSIVE OR

All logic instructions generate a result (new RLO). The first instruction in a logic string generates the new RLO from the signal state
scanned. The subsequent logic instructions generate the new RL from the signal state scanned and the old RLO. The logic string ends with
an instruction which limits the RLO (e.g. a memory instruction); that is, the FC bit is set to zero.
Instruc- Instruc- Address Address
tion ID
A/AN AND/AND NOT
O/ON OR/OR-NOT
X/XN EXCLUSIVE OR/ EXCLUSIVE-OR-NOT
Result=0
==0 (A1=0 and A0=0)
>0 Result>0
(CC1=1 and CC0=0)
<0 Result<0
(CC1=0 and CC0=1)
<>0
Result00
((CC1=0 and CC0=1) or (CC1=1 and
CC0=0))
Status word for: A/AN/O/ON/X/XN
Instruction evaluates:
Instruction affects:
S7-400 Instruction List
A5E00267845-01
Evaluating Conditions Using AND, OR and EXCLUSIVE OR
Description Description
BR CC1
– Yes
– –
Execution Time in ms
Length Length
in in
CPU 412 CPU 414
Words
1 0.1 0.06
1 0.1 0.06
1 0.1 0.06
1 0.1 0.06
CC0 OV OS
Yes – –
– – –
CPU 416 CPU 417
0.04 0.03
0.04 0.03
0.04 0.03
0.04 0.03
OR STA RLO
Yes – Yes
Yes Yes Yes
/FC
Yes
1
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