Settting to keep lock screen on?

Noob here: Is there a setting to keep the lockscreen on, particularly while charging?

I've looked everywhere, and can't find any... mine goes off after about 30 seconds or so.

I don't think there is a setting. I use an app called "No Screen Off" which gives you a toggle switch widget to keep the screen on or use the normal time out.
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Unfortunately, it doesn't seem to work on the lock screen.....

Looks like you are right. Sorry about that.