IAI PSEL, Operation Manual

Page: 607 / 1062

3. Program
113
[2] Program Format
Command, declaration
Extension
condition
(AND, OR)
Input condition
(I/O, flag)
Command,
declaration
Operand 1 Operand 2
Output
(Output port, flag)
E N, Cnd Cmnd Operand1 Operand2 Pst
The above is illustrated as follows in a ladder diagram.
(1) The conditions in front of the command are equivalent to “IF to THEN” for the BASIC
language.
IF to THEN
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x
ELSE
x x x x x x x x
To next step
1) The command will be executed if the input conditions meet the requirement. If there is an
indication for the output, it turns the output port on, and if the input conditions do not meet
the requirement, it moves to the next step.
2) If no condition is set, the command is executed unconditionally.
3) To use the condition in reverse (using the so-called contact b logic), add “N” (NOT) to the
condition.
4) You can use an input port, output port or flag for the input condition.
5) Operands 1 and 2, and the output, can be specified indirectly.
(2) Operation of the output, specified after the command and operands 1 and 2, is explained
below.
1) In the case of an actuator operation control command, etc., the output turns OFF the
moment the command execution is started and turns ON when the execution is completed.
In the case of a calculation command, etc., the output turns ON when the result becomes
a certain value and turns OFF with other values.
2) You can use an output port or flag for the output.
Output Command Operand 1 Operand 2
Output
Command Operand 1 Operand 2
Input condition
Output
Command Operand 1 Operand 2
Input condition