Omron CP - PROGRAMMING MANUAL 05-2007 - Page 1039

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Block Programming Instructions Section 3-30
Using a Bit Operand for LEND(810) or LEND(810) NOT
Both LEND(810) and LEND(810) NOT can be programmed with an operand
bit. If the operand bit is OFF for LEND(810) (or ON for LEND(810) NOT), exe-
cution of the loop is repeated starting with the next instruction after
LOOP(809). If the operand bit is ON for LEND(810) (or OFF for LEND(810)
NOT), the loop is ended and execution continues to the next instruction after
LEND(810) or LEND(810) NOT.
Note (1) Execution inside a loop does not refresh I/O data. If I/O data must be re-
freshed during the loop, use IORF(184).
(2) The maximum cycle time can be exceeded if loops are repeated too long.
Design the program so that the maximum cycle time is not exceeded.
Flags
Precautions Loops cannot be nested within loops.
Incorrect:
LOOP(809)
LOOP(809)
LEND(810)
LEND(810)
Do not reverse the order of LOOP and LEND.
Incorrect:
LEND(810)
:
:
LOOP(809)
LEND R (LEND NOT B)
Operand
bit ON
Operand
bit OFF
Operand
bit OFF
Operand
bit OFF
Loop repeated
Note
The status of the operand bit would be reversed for LEND(810) NOT.
Name Label Operation
Error Flag ER ON if a Loop Control Instruction is not in a block program.
OFF in all other cases.