40 CFR 90.412 - Data logging.
(a) A computer or any other automatic data collection (ADC) device(s) may be used as long as the system meets the requirements of this subpart.
(b) Determine from the data collection records the analyzer responses corresponding to the end of each mode.
(c) Record data at a minimum of rate of one Hz (one time per second).
(d) Determine the final value for power by averaging the individually calculated power points for each value of speed and torque recorded during the sampling period. As an alternative, the final value for power can be calculated from the average values for speed and torque, collected during the sampling period.
(e) Determine the final value for CO2, CO, HC, and NOX concentrations by averaging the concentration of each point taken during the sample period for each mode.