255.255.255.255 is NEVER the correct setting.
255.255.255.0 is the correct setting for many home Networks.
When you make changes, you must click the Apply button and/or close the window and save changes. Occasionally, a Restart can also be helpful in getting changes applied.
The best bet for many Users is to set it up again from scratch, using:
System Preferences > Network > Ethernet > (assist Me) > ( Assistant ) and being certain to specify a new location-file, and NOT use the default. This allows you to walk away from any pre-conceived notions left over from previous set-ups.
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You should be able to connect both your computer and that industrial controller to your Router, if you wish. Otherwise, you will indeed have to set up IP addresses and subnet masks manually.