172
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
7 Basic Instruction
7.6 ORB
7.6
ORB
Outline
A circuit in which two or more contacts are connected in series is called serial circuit block.
1. Instruction format
2. Applicable devices
Explanation of function and operation
1. ORB instruction (parallel connection of multiple contact circuits)
When connecting serial circuit blocks in parallel, use LD or LDI instruction at the start of branch, and use
ORB instruction at the end of branch.
ORB instruction is an independent instruction not associated with any device number in the same way as
ANB instruction described later.
When there are many parallel circuits, ORB instruction can be used for each circuit block to connect them.
Caution
There is no limitation in the number of parallel circuits which can be connected by ORB instructions (in the
case of appropriate program shown above).
Though ORB instructions can be used at one time, note that the repeated use of LD or LDI instruction is
limited to 8 or less (in the case of inappropriate program shown above).
Instruc-
tion
Bit Devices
Word Devices
Others
System User
Digit Specification
System User
Special
Unit
Index
Con-
stant
Real
Number
Charac-
ter String
Pointer
X Y M T C S D
.b KnX KnY KnM KnS
T
C
D
R U
\G
V
Z Modify K
H
E
"
"
P
ORB
There are no applicable devices.
ORB
OR Block
Basic Instruction
1 step
ORB
−
Continuous
Operation
Pulse (Single)
Operation
Mnemonic
Operation Condition
Circuit program
List program
X000
X001
Y006
X002
X003
X004
X005
Serial circuit block
Appropriate program
0000 LD
X000
0001 AND X001
0002 LD
X002
0003 AND X003
0004
0005 LDI
X004
0006 AND X005
0007
0008 OUT Y006
ORB
ORB
Inappropriate program
0000 LD
X000
0001 AND X001
0002 LD
X002
0003 AND X003
0004 LDI
X004
0005 AND X005
0006
0007
0008 OUT Y006
ORB
ORB
ORB instruction
ORB instruction