Plc meets Japanese disco after-sales engineer. Have you ever heard such suffocating words? Is it ignorance to ask others questions?

Maybe he misunderstood you and thought you were an ordinary member. It's best not to be a stranger. In my impression, the Japanese are also very respectful and serious about technology. If I were you, I would embarrass him. Give him some color to see see He may be a field equipment repairman. Don't take him personally too seriously. There's no need to get angry. I'll take care of them when I have the chance.