Programming instructions

Special Shortcut

It may appear that this very small program takes a long time to download. This is

because no matter how many ladder logic steps are in the program, GX-

Developer always downloads at least 8000 steps for the FX2N. It is possible to

speed the process considerably. Be careful if using this function to ensure all

code including the END statement is downloaded.

1) Take note of the final step number next to the rung with the END

statement.

2) Go to the Online menu and select Write to PLC.

3) Select Main.

4) Click on Program tab.

5) Click Step Range Specification.

6) In the End textbox, enter the final step number.

7) Click on Execute.

11.5 Online Editing

So far we have written a small program and then downloaded it to the PLC.

Since the program change was done in the computer only, this is called Offline

Editing. If the computer is connected to the PLC it is possible to change the

program directly in the PLC, avoiding the need to download or stop the PLC.

This is called Online Editing.

Note: FX PLCs prior to the FX2N must have RAM memory to do online editing.

The FX2N and above can do online editing to RAM and EEPROMs.

1) Click on the Online pull down menu

2) Go to ‘Monitor’

3) Click on Monitor(Write Mode)

4) Change the rung so that it looks like the one below

Note: You will need to convert the rung that you create.

At this point the new program exists in the PLC, but not on your hard drive. This

is a good time to save your project.

The circuit you created is called a LATCH and HOLD circuit and is very

common. X10 is a momentary contact, such as a pushbutton, that starts a

machine. Without the branch, the machine would only run as long as the

pushbutton was held down. Now Y0 turns on and keeps the branch true, even

though X10 is off. It is necessary to toggle the stop button, X11, to turn the

machine off.