1 cup brown rice, 1 1/2 cups water or stock
This kind of pressure cooker doesn't have a jiggler. It has a little button that pops up to let you know that the pot is at pressure. You can watch the button in action by clicking on the video on my website.
In my DVD Pressure Cooking: A Fresh Look, Delicious Dishes in Minutes, I cook red rice with lentils. I use a long grain red rice from Thailand which keeps turning out different with varying amounts of water and rice. So far, 1 cup of rice to 2 cups of water, cooked for 9 to 10 minutes with a natural pressure release seems to work fine, most of the time.
Here's the rub with cooking grains -- how they cook depends upon that batch of grains, how old it is, how it's been stored which effects the moisture level, and other intangible factors. So, following the recipe will work most of the time. You need a jumping off point so this might help.
Another tip: when cooking more than 1 cup of rice, reduce the amount of liquid by 1/4 cup for each additional cup of grain. Here's how this translates into cooking: for the 1st cup of brown rice you use 1 1/2 cups water and for the second cup you use 1 1/4 cups water. Two cups of brown rice requires 2 3/4 cups water in the pressure cooker. This works well for stove top cooking, too.
I do this because I do not care for soggy grains. Do you?