Delta MH300 Series - Page 884

Chapter 16 PLC Function ApplicationsMH300
16-21
Explanation of basic structure of ladder diagrams
LD (LDI) command: an LD or LDI command appears at the start of a block. See Figure 16-30.
AND Block OR Block
LD command LD command
Figure 16-30
LDP and LDF use 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 16-31).
X0
OFF
ON
OFF
Time
Falling-edge
X0
OFF
ON
OFF
Time
Rising-edge
Figure 16-31
AND (ANI) command: a series configuration in which a single device is connected with one device
or a block. See Figure 16-32.
AND command AND command
Figure 16-32
NOTE:
ANDP, ANDF use this structure, but their action occurs at the rising and falling edge of a conducting
contact.
OR (ORI) command: a single device is connected with one device or a block. See Figure 16-33.
OR command OR command OR command
Figure 16-33
NOTE:
ORP, ORF use this structure, but their action occurs at the rising and falling edge of a conduction
contact.