
B-63983EN/02 8.LADDER DIAGRAM MONITOR AND EDITOR SCREENS ([PMC LADDER])
- 833 -
8.3.4 Structure of Valid Net
Valid net must have following structure:
Input section
Output
section
Convergence point
Structure of valid net
"Input section" consists of contacts and functional instruction, and the
result of operations of input section is led to "Convergence point".
After the convergence point, there is "Output section" that consists of
coils only. The "Convergence point" is the nearest point to right
power line, where all connections join with each other to gather into
single connection.
Output
section
Convergence
point
Input section
Sample of valid net
Input section contains at least one relay or functional instruction,
however, output section may contain nothing.
Example of net with no output section
Valid net is also restricted in following rules:
· Only one functional instruction is available for a net.
· Functional instruction can be placed only at last (rightmost) of input
section.
· Only coils can be contained in output section.