40 CFR 89.409 - Data logging.
(a) A computer or any other automatic data processing 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 once every 5 seconds.
(d) 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.
(e) For purposes of this section, calibration data includes calibration curves, linearity curves, span-gas responses, and zero-gas responses.