Basic Information On Instructions - Omron SYSMAC CS Series Programming Manual

Basic Concepts
2-1-2

Basic Information on Instructions

ower flow (P.F., execution condition)
nstruction condition
lags
Power Flow
Input Instructions
Output Instructions
Instruction Conditions
Instruction
condition
Interlocked An interlock turns OFF part of the program. Special conditions, such as
turning OFF output bits, resetting timers, and holding counters are in
effect.
BREAK(514) Ends a FOR(512) - NEXT(513) loop during execution. (Prevents execu-
execution tion of all instructions until to the NEXT(513) instruction.)
Executes a JMP0(515) to JME0(516) jump.
Block program Executes a program block from BPRG(096) to BEND(801).
execution
Programs consist of instructions. The conceptual structure of the inputs to and
outputs from an instruction is shown in the following diagram.
Instruction
Operands
Operands
(destinations)
(sources)
Memory
The power flow is the execution condition that is used to control the execute
and instructions when programs are executing normally. In a ladder program,
power flow represents the status of the execution condition.
• Load instructions indicate a logical start and outputs the execution
condition.
• Intermediate instructions input the power flow as an execution condi-
tion and output the power flow to an intermediate or output instruction.
Output instructions execute all functions, using the power flow as an execu-
tion condition.
LD power flow
Input block
Instruction conditions are special conditions related to overall instruction exe-
cution that are output by the following instructions. Instruction conditions have
a higher priority than power flow (P.F.) when it comes to deciding whether or
not to execute an instruction. An instruction may become not be executed or
may act differently depending on instruction conditions.
Instruction conditions are reset (canceled) at the start of each task, i.e., they
are reset when the task changes.
The following instructions are used in pairs to set and cancel certain instruc-
tion conditions. These paired instructions must be in the same task.
Description
Power flow (P.F., execution condition)*
2
Instruction condition*
Flag
*1: Input instructions only.
*2: Not output for all instructions.
Power flow for
output instruction
Output block
Setting
instruction
IL(002)
BREAK(514)
JMP0(515)
BPRG(096)
Section 2-1
1
Canceling
instruction
ILC(003)
NEXT(513)
JME0(516)
BEND(801)
21