How to Use the Step Ladder Program Block
Appendix 1
207
List of Basic Instructions
: Can be used
:
Cannot be used
Command
Command
code
Ladder symbol
Operand
Description
Input
conditions In logic
sequence
In step
sequence
LOAD
01
Read
source
block
address/
ITEM
number
Indicates a logical start
of the logic block,
creates an ON/OFF
execution condition
based on the ON/OFF
status of the contact,
and connects to the next
stage.
Not required
LOAD NOT
02
Read
source
block
address/
ITEM
number
Indicates a logical start
of the logic block,
creates an ON/OFF
execution condition
based on the reverse of
the ON/OFF status of
the contact, and
connects to the next
stage.
Not required
AND
03
Read
source
block
address/
ITEM
number
Takes a logical AND of
the status of the contact
and the current
execution condition.
Required
AND NOT
04
Read
source
block
address/
ITEM
number
Reverses the status of
the contact and takes a
logical AND with the
current execution
condition.
Required
OR
05
Read
source
block
address/
ITEM
number
Takes a logical OR of
the status of the contact
and the current
execution condition.
Required
OR NOT
06
Read
source
block
address/
ITEM
number
Reverses the status of
the contact and takes a
logical OR with the
current execution
condition.
Required
AND LOAD
07
Circuit block
Circuit block
000000
(fixed)
Takes a logical AND
between circuit blocks.
Required
(2 or more)
Input t
y
p
e
OR LOAD
08
Circuit block
Circuit block
000000
(fixed)
Takes a logical OR
between circuit blocks.
Required
(2 or more)