7-11
Section
INTERLOCK and INTERLOCK CLEAR – IL(02) and ILC(03)
381
DIFU(13) and DIFD(14) operation can be uncertain when the instructions are
programmed between IL and ILC, between JMP and JME, or in subroutines. Re-
fer to
7-11
INTERLOCK and INTERLOCK CLEAR – IL(02) and ILC(03)
,
7-12
JUMP and JUMP END – JMP(04) and JME(05)
,
7-26 Subroutine Instructions
,
and
7-29-1 INTERRUPT CONTROL – INT(89).
In this example, IR 20014 will be turned ON for one cycle when IR 00000 goes
from OFF to ON. IR 20015 will be turned ON for one cycle when IR 00000 goes
from ON to OFF.
DIFU(13) 20014
00000
Address
Instruction
Operands
00000
LD
00000
00001
DIFU(13)
20014
00002
DIFD(14)
20015
DIFD(14) 20015
7-9
NO OPERATION – NOP(00)
NOP(00) is not generally required in programming and there is no ladder symbol
for it. When NOP(00) is found in a program, nothing is executed and the program
execution moves to the next instruction. When memory is cleared prior to pro-
gramming, NOP(00) is written at all addresses. NOP(00) can be input through
the 00 function code.
Flags
There are no flags affected by NOP(00).
7-10 END – END(01)
Ladder Symbol
END(01)
END(01) is required as the last instruction in any program. If there are subrou-
tines, END(01) is placed after the last subroutine. No instruction written after
END(01) will be executed. END(01) can be placed anywhere in the program to
execute all instructions up to that point, as is sometimes done to debug a pro-
gram, but it must be removed to execute the remainder of the program.
If there is no END(01) in the program, no instructions will be executed and the
error message “NO END INST” will appear.
Flags
END(01) turns OFF the ER, CY, GR, EQ, and LE flags.
7-11 INTERLOCK and INTERLOCK CLEAR – IL(02) and ILC(03)
Ladder Symbol
IL(02)
Ladder Symbol
ILC(03)
IL(02) is always used in conjunction with ILC(03) to create interlocks. Interlocks
are used to enable branching in the same way as can be achieved with TR bits,
but treatment of instructions between IL(02) and ILC(03) differs from that with
TR bits when the execution condition for IL(02) is OFF. If the execution condition
of IL(02) is ON, the program will be executed as written, with an ON execution
condition used to start each instruction line from the point where IL(02) is located
through the next ILC(03). Refer to
6-3-8 Branching Instruction Lines
for basic
descriptions of both methods.
Precautions
Example
Description
Description
Description