
50
The next and final example may at first appear very complicated but can be
coded using only two logic block instructions. The diagram appears as fol-
lows:
0000
0001
0100
0002
0003
0010
0011
0004
0005
0100
0106
Block c
Block b
Block a
The first logic block instruction is used to combine the execution conditions
resulting from blocks a and b, and the second one is to combine the execu-
tion condition of block c with the execution condition resulting from the nor-
mally closed condition assigned bit 0003. The rest of the diagram can be
coded with OR, AND, and AND NOT instructions. The logical flow for this
and the resulting code are shown below.
0000
0001
0100
0002
0003
0010
0011
0004
0005
0100
0106
Block c
Block b
Block a
OR LD
LD
0000
AND
0001
OR
0100
AND
0002
AND NOT 0003
LD
0010
AND
0011
LD
0106
LD
0004
AND
0005
AND LD
Address
Instruction
Operands
000
LD
0000
001
AND
0001
002
LD
0010
003
AND
0011
004
OR LD
--
005
OR
0100
006
AND
0002
007
AND NOT
0003
008
LD
0004
009
AND
0005
010
OR
0106
011
AND LD
--
012
OUT
0100
3-4-7
Coding Multiple Right-hand Instructions
If there is more than one right-hand instruction executed with the same ex-
ecution condition, they are coded consecutively following the last condition
Basic Programming
Section 3-4