Program Execution; Using Version-2 Cvm1 Cpus; Input Comparison Instructions - Omron SYSMAC CV Series Operation Manual

Using Version-2 CVM1 CPUs

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4-11 Program Execution

4-12 Using Version-2 CVM1 CPUs

4-12-1 Input Comparison Instructions

When drawing ladder diagrams, it is important to keep in mind the number of
instructions that will be required to input it. In diagram A, below, an OR LOAD
instruction will be required to combine the top and bottom instruction lines. This
can be avoided by redrawing as shown in diagram B so that no AND LOAD or OR
LOAD instructions are required. Refer to 5-6-5 AND LOAD and OR LOAD for
more details and 4-4-1 Logic Block Instructions for further examples of diagrams
requiring AND LOAD and OR LOAD.
Diagram A
Diagram B
When execution or a ladder diagram is started, the CPU scans the program from
top to bottom, checking all conditions and executing all instructions accordingly
as it moves down the bus bar. It is important that instructions be placed in the
proper order so that, for example, the desired data is moved to a word before that
word is used as the operand for an instruction. Remember that an instruction line
is completed to the terminal instruction at the right before executing instruction
lines branching from the first instruction line to other terminal instructions at the
right.
Program execution is only one of the tasks carried out by the CPU as part of the
scan time. Refer to Section 6 Program Execution Timing for details.
The most significant improvement that the version-2 CVM1 CPUs offers in com-
parison with version-1 CPUs is a greatly enhanced instruction set. This section
explains the basics that the user should be familiar with before attempting to use
the new instructions. All of these instructions can be used when the SYSMAC
Support Software and the CVM1-PRS21-EV1 Programming Console are used.
They are not supported by the CVSS or other Programming Devices.
The version-2 CVM1 CPUs provide 24 new comparison instructions. The func-
tions of these instructions are shown as symbols, making them easy to under-
stand at a glance.
0002
Address Instruction
07
00000 LD
00001 LD
00002 AND
00003 OR LD
00004 OUT
0002
07
Address Instruction
00000 LD
00001 AND
00002 OR
00003 OUT
Section 4-12
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