A portable articulated arm coordinate measurement device is provided. The device comprises: a top surface and a bottom surface of the device. A signal is generated from the coil responsive to the time-varying signal and to the magnetic field, wherein the signal provides for sensing an opening state of the door and for sensing a crash involving the door. The semiconductor storage device can permanently inactivate further programming of the redundancy circuit in order to prevent a user from performing inadvertent programming. The system may determine first positions and the second positions of the corresponding features using the first camera image and the second camera image.