Over-current shutdown, as well as current surges greater than 500 ms are detected by the B881–508. Each point has a fault bit that can be accessed using the programming panel software. Each bit indicates either an over-current (greater than 30 A), or a current surge between 5 -3 A for a period greater than 500 ms. Although the B881-508 is I/O mapped as a 16-point bi-directional module, only the lower order eight inputs and outputs are used; the higher order eight inputs and outputs can not be used. Refer to the illustration below.