If you are traveling through China, or on a Chinese airplane, anything with a lithium battery will trip their detectors. You will only be allowed to have one lithium battery that is not in your phone or laptop, and it's size is very limited. This includes spares, battery banks and batteries in things like flashlights and PLC's.
One thing on PLC's to watch for is if the technology is prohibited to be exported to any of the countries you will be landing in. Sometimes even a programmable display will not be allowed to go to the country you are changing planes in.
Also, landing in many countries with tools will cause problems. I take the advice I got here and travel without tools, buy what I need when I get there, and donate them to the local workers when I leave - a lot less headaches.
Or, if you really need or want your tools, ship them FedEx or DSL to be there when you get there, coming home with tools generally isn't a problem.