FYI if you are new to a PC.
The length of time it take to pressure depends on your food and altitude.
My altitude is 5,200 feet
I cook a roast about 1 1/2 to 2 hours or till fall apart.
I cook beans 2 hours [just wash and cook, no soaking]
In Dallas the altitude is 430 feet, these cook times are cut in half- it is a lower altitude
Judge your cook time by your altitude not the book,use the book as a guide to start with.
The longer you cook it the more you cook out your vitamins.