Delta CT2000 Series User Manual page 459

Chapter 16 PLC Function CT2000 Series
Explanation of basic structure of ladder diagrams
LD (LDI) command: An LD or LDI command is given at the start of a block.
LDP and LDF have this command structure, but there are differences in their action state. LDP, LDF
only act at the rising or falling edge of a conducting contact. (see figure below):
Rising-edge
X0
AND (ANI) command: A series configuration in which a single device is connected with one device
or a block.
ANDP, ANDF also have structures like this, but their action occurs at the rising and falling edge.
OR (ORI) command: A single device is connected with one device or a block.
ORP, ORF also have identical structures, but their action occurs at the rising and falling edge.
ANB command: A configuration in which one block is in series with one device or block.
LD command
AND Block
OFF
ON
OFF
AND command
OR command
LD command
OR Block
X0
Time
AND command
OR command OR command
ANB command
16-18
Falling-edge
OFF
ON
OFF
Time