Making the CAN bus a 'can-do' bus

摘要

When your instrument rusts under five feet of snow, on the summit of Greenland's ice cap, at 70 degrees latitude and an altitude of 4000 meters, you'd rather not have to dig it up to get your data out. The Space Physics Research Laboratory at the University of Michigan (www.sprl.umich.edu) recently placed a magnetometer in exactly this situation, so designers of the instrument provided a way to upload its data to a laptop PC. Earlier versions of the instrument used a serial port to transfer the data. This technique became impractical when designers modified the instrument to log magnetic readings at 10 times the former frequency. Even after compressing the readings, the instrument now produces as much as 400 Mbytes of data in one year of unattended operation. The challenge is uploading that much data in a reasonable amount of time―meaning less than the maximum on-battery time of a laptop PC in cold weather.