Principles of uniqueness to the design of ladder diagram, or PLC programming increased constraints, starting with design and programming but also to bring ideas.
The analytical program described here is to start from the principle of analysis only, specific steps are:
1) column to the original source for the meter: according to the PLC the object of work, Division of work beats, and correspond to the input and output of each beat, initial power up table, this table is also known as the original power table. It is only the design requirements of “form“, it is possible to reflect the relationship between output and input in all beat.
2) unique design: for example, the original table checked for uniqueness, if when mixing beats, with increased internal auxiliary generator be distinguished. Then, check whether the auxiliary relays meet the uniqueness principle. If there are mixed, add, check it again, until all meet the unique principles.
3) logical expression: according to power table lists the output relays and auxiliary relays inside logical expressions.
4) simplify the logic: to simplify the logical expression to get the simplest form.
5) draw a ladder diagram: in the simplest form draw a ladder diagram.
PLC ONE 