Programming instructions

11.6 Monitor the Program Operation

It is possible to view what’s happening in the program, and to check the states of

program bits, in GX-Developer. This process of viewing is called Monitoring the

program.

1) Click on the ‘Online’ pull down menu

2) Go to ‘Monitor’

3) Select ‘Monitor Mode’

A small box will pop up, indicating the mode (run or stop) of the PLC and the

average scan time for the program.

You should notice that X10 and Y0 are not highlighted, and X11 is highlighted.

This indicates whether an input device is conducting or not, or an output device is

energized. A highlighted contact is conducting, and a highlighted coil is

energized. X10 and Y0, which are checking to see their input and output

respectively are on, aren’t true. X11 on the other hand, which is checking the

input to see that it is off, is true.

Turn X10 on by toggling the switch. When the switch is toggled on, the bit in the

program highlights. Toggle X11 off. Notice that the bit is not highlighted

anymore. Set X11 and X10 so that both are highlighted. When all the contacts

on a rung are highlighted, we say that the rung is TRUE. When a rung is true,

the output turns on. Notice that Y0 is highlighted on the screen and that the Y0

bulb is lit on the trainer.

Entry Ladder Monitor

This feature allows the programmer to monitor multiple rungs in a non-sequential

manner.

1) Copy and Paste the above rung 3 times. Change the addresses of the

contacts and coils to create 4 separate rungs

2) Put the program into Monitor Mode

3) Go to Online Æ Monitor Æ Entry Data Ladder

4) Go to Window Æ Tile Horizontally

5) In the bottom window click on the 4

rung to highlight it

6) Click and hold on the highlighted rung, drag it to the upper screen and release

7) Repeat steps 5 and 6 for the 1st rung and the 3

rung.

8) Click on the upper window to make it the active window and maximize it

9) Put the window into Monitor Mode

10) Toggle switches and watch the results