As with any popular PLC programming software, GX Works 3 not only allows you to upload and download programs, but also supports program compare and verify as well as viewing ladder differences graphically.

Photo by Jordan Harrison on Unsplash

But before you can do any of that, you first need to know how to connect GX Works 3 to your controller, which I’ll cover in the below steps:

Note: If you’re coming to GX Works3 from GX Works2 or earlier, feel free to check out the first article in the series, Mitsubishi GX Works Communications Setup which covers some of the differences between the GX2 and GX3 software.

Step 1) When connecting to the PLC, if you have not connected to this processor previously (or if you’ve connected to another network and have come back) be sure you start by clicking on the connection destination (bottom of Navigation window)

Image by Paul Hunt

Step 2) Next, Double click “Connection” under “Current Connection Destination”

Step 3) From here, you can select the button “Directly Connected to CPU”. This usually works for me even if connected through a hub or switch.  As I am sure you are aware, things may differ from system to system and OS to OS.  Find which one works best for your setup.

Image by Paul Hunt

Step 4) Be sure your NIC card is the selected adapter in the pull-down list and the IP address is valid for the network/PLC you are going to connect to.

Image by Paul Hunt

Step 5) For good measure, press the “Connection Test “button and you will see that it has found your CPU.

Now that you are connected you can go online, upload, download, or verify the project with what is loaded in the CPU.

You can select these by using the Online pull-down menu or the quick access icons at the top of your toolbar.

Online Write And Read Options, Image By Paul Hunt

To verify, you can select that option on the pull down or from the dialog window that pops up when selecting the items to read/write.

Full Online Menu, Image By Paul Hunt

Now the key thing to remember here is this is where Mitsubishi is different. You can select individual items (to a point) to download or upload.

If you make a change to some recipe value on the HMI that is stored in the Device Memory, you can upload that individually.  This comes in handy, for instance, when you make a ladder or parameter change.

You can upload device memory separately before downloading your changes to avoid losing that changed recipe value.  Or perhaps you need to just change a parameter.  You can download just the parameter settings without downloading memory, labels, or program files.

We’ll cover those more advanced functions in detail in future articles.

Written by Paul Hunt
Senior Automation Engineer and Freelance Writer

Have a question? Join our community of pros to take part in the discussion! You'll also find all of our automation courses at

Sponsor and Advertise: Get your product or service in front of our 75K followers while also supporting independent automation journalism by sponsoring or advertising with us! Learn more in our Media Guide here, or contact us using this form.

Paul Hunt



Please enter your comment!
Please enter your name here