Chapter 16 PLC Function ApplicationsMS300
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Explanation of basic structure of ladder diagrams
1. LD (LDI) command: An LD or LDI command appears at the start of a block.
Figure 16-29
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 diagram below).
Figure 16-30
2. AND (ANI) command: a series configuration in which a single device is connected with one
device or a block.
Figure 16-31
ANDP, ANDF use this structure, but their action occurs at the rising and falling edge of a
conducting contact.
3. OR (ORI) command: a single device is connected with one device or a block.
Figure 16-32
ORP, ORF use this structure, but their action occurs at the rising and falling edge a conduction
contact.
4. ANB command: a configuration in which one block is in series with one device or block.
Figure 16-33