Mnemonic Code; The End Instruction; Logic Block Instructions - Omron SYSMAC CV Series Operation Manual

Mnemonic Code

4-3-5 The END Instruction

0000
00
4-4

Mnemonic Code

4-4-1 Logic Block Instructions

80
In the above examples, CIO 000200 will be ON as long as CIO 000000 is ON and
CIO 000201 will be ON as long as CIO 000001 is OFF. Here, CIO 000000 and
CIO 000001 would be input bits and CIO 000200 and CIO 000201 output bits
assigned to the Units controlled by the PC, i.e., the signals coming in through the
input points assigned CIO 000000 and CIO 000001 are controlling the output
points to which CIO 000200 and CIO 000201 are allocated.
The length of time that a bit is ON or OFF can be controlled by combining the
OUTPUT or OUTPUT NOT instruction with Timer instructions. Refer to Exam-
ples under 5-13-1 Timer – TIM for details.
The last instruction required to complete any program is the END instruction.
When the CPU scans a program, it executes all instructions up to the first END
instruction before returning to the beginning of the program and beginning
execution again. Although an END instruction can be placed at any point in a
program, which is sometimes done when debugging, no instructions past the
first END instruction will be executed. The number following the END instruction
in the mnemonic code is its function code, which is used when inputting most
instructions into the PC. Function codes are described in more detail later. The
END instruction requires no operands and no conditions can be placed on the
instruction line with it.
0000
01
If there is no END instruction anywhere in a program, the program will not be
executed at all.
Logic block instructions do not correspond to specific conditions on the ladder
diagram; rather, they describe relationships between logic blocks. Each logic
block is started with a LOAD or LOAD NOT instruction. Whenever a LOAD or
LOAD NOT instruction is executed, a new execution condition is created and the
previous execution condition is stored in a buffer. The AND LOAD instruction
logically ANDs the execution conditions produced by two logic blocks, i.e., gen-
eral speaking, it ANDs the current execution condition with the last execution
condition stored in a buffer. The OR LOAD instruction logically ORs the execu-
tion conditions produced by two logic blocks.
Address Instruction
00500
Instruction
00501
(001)
00502
Program
END
execution
00503
ends here.
Section 4-4
Operands
LD 000000
AND NOT 000001
Instruction
END(001) ---