Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual page 373

Controlling Bit Status
00100
00101
6-4-2 DIFFERENTIATE UP and DIFFERENTIATE DOWN
00000
00001
6-4-3 KEEP
SET will turn ON the operand bit when the execution condition goes ON, but un-
like the OUTPUT instruction, SET will not turn OFF the operand bit when the
execution condition goes OFF. RESET will turn OFF the operand bit when the
execution condition goes OFF, but unlike OUTPUT NOT, RESET will not turn ON
the operand bit when the execution condition goes OFF.
In the following example, IR 20000 will be turned ON when IR 00100 goes ON
and will remain ON until IR 00101 goes ON, regardless of the status of IR 00100.
When IR 00101 goes ON, RESET will turn IR 20000 OFF.
Note SET and RSET do not have function codes. To input them from the Program-
ming Console, press the FUN and SET Keys or FUN and RSET Keys followed
by the bit address.
DIFFERENTIATE UP and DIFFERENTIATE DOWN instructions are used to
turn the operand bit ON for one cycle at a time. The DIFFERENTIATE UP
instruction turns ON the operand bit for one cycle after the execution condition
for it goes from OFF to ON; the DIFFERENTIATE DOWN instruction turns ON
the operand bit for one cycle after the execution condition for it goes from ON to
OFF. Both of these instructions require only one line of mnemonic code.
Here, IR 20001 will be turned ON for one cycle after IR 00000 goes ON. The next
time DIFU(13) 20001 is executed, IR 20001 will be turned OFF, regardless of the
status of IR 00000. With the DIFFERENTIATE DOWN instruction, IR 20002 will
be turned ON for one cycle after IR 00001 goes OFF (IR 20002 will be kept OFF
until then), and will be turned OFF the next time DIFD(14) 20002 is executed.
The KEEP instruction is used to maintain the status of the operand bit based on
two execution conditions. To do this, the KEEP instruction is connected to two
instruction lines. When the execution condition at the end of the first instruction
line is ON, the operand bit of the KEEP instruction is turned ON. When the
execution condition at the end of the second instruction line is ON, the operand
bit of the KEEP instruction is turned OFF. The operand bit for the KEEP instruc-
tion will maintain its ON or OFF status even if it is located in an interlocked sec-
tion of the diagram.
Address Instruction
SET 20000
00000
00001
00002
RSET 20000 00003
Address Instruction
DIFU(13) 20001
00000
00001
DIFD(14) 20002
Address Instruction
00000
00001
Section
Operands
LD 00100
SET 20000
LD 00101
RSET 20000
Operands
LD 00000
DIFU(13) 20001
Operands
LD 00001
DIFD(14) 20002
6-4
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