Based: PLC ladder diagram of the six - programming rules

Ladder diagram programming rules: described in the previous section the composition character of ladder diagram, is also a ladder diagram programming some basic rules, the article introduces a few here.

1, the contact can't pick up on the right side of the coil; Coil cannot be directly connected to the left bus bar, must through the contact link.

2, at the end of each logical line, when several branch and series contact more should be ranked above; A few line series, parallel contact more should be on the left. This reduces programming instructions.

3, ladder diagram of contact should draw on the horizontal branch, not painted in the vertical branch.

5, not double coil output, double coil output is to point to in a program, the same output cannot use more than 2 times and the secondary coil. If there is a double coil, the former one or the previous coil output invalid, only the last coil output effectively.

6, ladder diagram, in addition to input relay X not only contact wire coil, other relay existing lines, and the contact.

in addition to the above a few basic rules, and some rules must be combined with the instruction given to introduce, to speak. Ladder diagram is illustrated below, one of the recommended drawing for reference.

in this chapter, we learned a lot of the basic knowledge of programming. May temporarily without some knowledge, but it is necessary to master the basic knowledge; Some knowledge we are not in-depth explanation, but in the practical application in the future, you will gradually deepen understanding.