FX Series Programmable Controllers Basic Program Instructions 2
2-11
2.11 Or Block
Program example:
Basic points to remember:
- An ORB instruction is an independent instruction and is not associated with an
device
number.
- Use the ORB instruction to connect multi-contact circuits (usuall
serial circuit blocks) to
the precedin
circuit in parallel. Serial circuit blocks are those in which more than one
contact connects in series or the ANB instruction is used.
- To declare the startin
point of the circuit block use a LD or LDI instruction. After
completin
the serial circuit block, connect it to the precedin
block in parallel usin
the
ORB instruction.
Mnemonic Function Format Devices Program steps
ORB
(OR Block)
Parallel connection
of multiple contact
circuits
N/A 1
X0 X1
X2 X3
ORB
X4 X5
ORB
LD
AND
LD
AND
ORB
ORB
LDI
AND
0
1
2
3
4
6
7
5
8 OUT
X
X
X
X
X
0
1
2
3
4
Y
X
5
6
LD
AND
LD
AND
LDI
ORB
AND
ORB
0
1
2
3
4
6
7
5
8 OUT
X
X
X
X
X
0
1
2
3
5
Y6
X4
Recommended sequential
programming method
Non-preferred batch
programming method
Y6
Batch processing limitations:
• When usin
ORB instructions in a batch, use no more than 8 LD and LDI instructions
in the definition of the pro
ram blocks (to be connected in parallel). I
norin
this will
result in a pro
ram error (see the ri
ht most pro
ram listin
).
Sequential processing limitations:
• There are no limitations to the number of parallel circuits when usin
an ORB
instruction in the sequential processin
confi
uration (see the left most pro
ram
listin
).
