Using output address for an input in a program

• In the previous chapter we learnt that output address can be used as input address (NC or NO contact) in the rules for ladder diagram programming.
• The following example shows an output address (Q0.2) being used for an input. You can write the program in network 4 and simulate the program to see how it works:

Figure 9.31 – Output address (Q0.2) used for a normally open contact at input

The wiring diagram for the program is as follows:

Figure 9.32 – Wiring diagram to implement a program using output address for input

Let’s say a pilot lamp (PL3) is connected to Q0.3 as shown in the preceding figure.

Anytime Q0.2 is ON, the normally open contact with address Q0.2 will be closed since the coil with address Q0.2 is energized and PL3 connected to Q0.3 will be ON.

If we edit the program by replacing the normally open contact with address Q0.2 with a normally closed contact as shown in the following screenshot, the program...