Crank lenght to avoid RMP fail

Yesterday I had the chance to premiere my new neo2t. I'm experiencing problems with RPM readings. I wonder if my arm cranck is long enough to reach the sensor. In my case, the crank end is like 4-5 cm far away from the N of NEO 2T logo.

To confirm or discardm if the problem is this, my question is where exactly the sensor is and how close the crank end  it should pass.