Statements - Siemens SIMATIC S7-200 Manual

Statements

The control statement is the smallest unit of a PLC user program. A statement consists of an
operation part and an operand part.
Operation
(Do what ?)
The operation part of a statement (in this
case an AND logic operation) determines
the function that is performed when the
control statement is executed.
I 0 . 2
Hardware Software
Control Statements
E0.0
Structure of an operand
Bit address:
Decimal point:
Byte address:
Operand identifier
(area identifier)
Possible areas:
Basic
Settings
Operand
(... to what ?)
The operand part of a statement (in this case
input 0.0) contains the additional information
for the control statement. It consists of an
operand identifier and a parameter.
Operand identifier
The operand identifier spe-
cifies an area of the PLC.
In the above example, an
operation is performed on
an input. Other areas
include outputs and bit
memories.
bit number in the byte (0 to 7)
separates byte address & bit number
Number of a group of 8 bits
inputs, outputs,
Internal bit memories, special
memories, variable memories
1st Exercise More
Program Exercises
I 0.0
Parameter
The parameter is the
address of the
operand. It consists
of, e.g., a byte and
bit address.
Appendix 27