A PIN will only incur a cash advance if you use your card at an ATM machine to withdraw cash.
If you have a US issued chip card, it almost for sure is a signature based purchase validation. But some banks do issue a PIN as a secondary validation where a signature cannot be obtained, such as automated machines. In those cases, typically you would enter your PIN and the transaction is approved. Otherwise, your card will always require a receipt or electronic signature. Most tourist-based merchants will be familiar with that system and can accommodate you (sometimes saying "No PIN" helps). Occasionally cards without PINs are not accepted at all (such as Dutch railway ticket offices).
If your bank issued you a PIN for cash advances (and not to validate purchases), then the PIN probably won't work if you try and use it in an automated machine. But sometimes the machines are set to accept US cards without having to enter a PIN (or entering any 4 digit number will validate it). You can always try it and if it doesn't work, use cash or go to a staffed window.
Confused? You are not alone. It is not easy to understand because there are so many variables (on this side of the Atlantic and that side).