The machine uses a Yaskawa MP2300. There’s quite a few servo drives over Mechatrolink. We can go online with a browser (gotta use IE or IE mode in Edge) to send the parameters to a replacement drive and reach some other diagnostics. The actual PLC program is only saved as a binary and the source project the OEM doesn’t share would be needed to actually see or interact with the program.
It’s been a few years so I don’t recall the details but we could do it again. It’s more than just sending a value to a register. It requires some specific two way HTML to enable and disable the settings button. We did duplicate it with a Pi, but we never made a portable battery powered setup. The shop laptop is the public portable battery powered tool for it. It’s got a slow spinning rust drive with early Windows 10, and the battery is only good for maybe fifteen minutes from a full charge these days.
Edit: enable / disable is just more than the HMI button and must have some PLC code behind it. I recall we tried to just make the button visible and we either couldn’t reach the settings or changing the settings did nothing unless the unlock sequence was done.