A computing device receives a first digital signal from a data acquisition system. It is determined that a first value includes in the first signal indicates an event. A second digital signal is received from the data acquisition system. It is determined that a second value included in the second signal includes a value that indicates the event, and that the event has occurred based at least in part on the first value, the second value, and a passage of a predetermined duration of time between a time of the first digital signal and a time of the second digital signal.