RsLogix 500 - What can you learn from a blank program

In this lesson you are going to learn what the "blank" program you made from RsLogix 500 - Going Online with a PLC can do. 

Reconnect to the PLC and if necessary re-download the blank program.  Look back at the previous lessons if you need help doing this.

1.  In the left pane double click on the "O0 - OUTPUT" and "I1 - INPUT" data files.

 on6.png

 

2.  Arrange the two data files so you can see both of them at the same time.

on7.png

 

3.  Press "Button 1" on your trainer. Note that even though you have no logic in your program, when the button is press there is a 1 in the I:0.0/0 data box and when it is not pressed there is a 0 in the I:0.0/0 data box.

on8.png

 

4.  Now double click on the "0" in the O:0.0/0 data box circled below, change its value to a "1", then press enter.  

on9.png

 

5.  You should see "Light 1" illuminate.  Change it back in forth between a 1 and a 0 until you understand that the value in this data box is determining whether the Light is ON or OFF.

on10.png

 

6.  With the "Light 1" illuminated from step 9, unplug your trainer's power and allow the PLC to completely power down then power it up and go back online.  Note that the "Light 1" output remains illuminated.

on10.png

Conclusion 

The key take away from the steps above is that a PLC does things even without a program being executed and the lack of an instruction addressing an output does not mean that output is turned off.  This will be very important in later lessons.

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