Chapter 7 Programming

The user program is managed in circuit units. One circuit can describe nine contact points (a-type contact point or b-type contact point) and seven coils as shown in the figure below.

Figure 7.1 Size of one circuit

Or, one relational box can be described using the width of three contact points. The relational box can be considered as an a-type contact point that turns on when the conditions in the box are established (Figure 7.2).

Figure 7.2 Example when using a relational box

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Hitachi NJI-350B manual Size of one circuit