AOA tool

To set the angle of attack sensor to a certain angle we use a AOA rose.
There are different types of AOA sensors and different types of sensors. Usually we hook one up to both sides of the aircraft to simulate a certain aircraft nose up or nose down setting.

On this type we start with screwing the rose mount onto the fuselage.
AOA rose mount

Then we connect the rose onto the mounting block.
AOA rose

Now we can set the AOA sensor accurately to a certain setting. Here's 20 degrees nose down.
20 degrees

And here's 20 degrees nose up.
20 degrees

And here is 0 degrees. (level flight).
0 degrees

Now that we know that the sensor is physically placed in 0 degrees we can see if that is also what the sensor is sensing. In our case we have a SMYD (Stall Management Yaw Damper) computer.
SMYD