Document ID: chunk:federal_register_of_legislation:F2024L00447:front:0:p7
Version: federal_register_of_legislation:F2024L00447
Segment Type: other
Provision Reference: 
Character Range: 20248–23137

Figure 1.

              3.2.15. "Response time" (t90) means the difference in time between the change of the component to be measured at the reference point and a system response of 90 per cent of the final reading (t90) with the sampling probe being defined as the reference point, whereby the change of the measured component is at least 60 per cent full scale (FS) and takes place in less than 0.1 second. The system response time consists of the delay time to the system and of the rise time of the system, as depicted in Figure 2.

              3.2.16. "Rise time" means the difference in time between the 10 per cent and 90 per cent response of the final reading (t10 to t90), as depicted in Figure 2.

              3.2.17. "Sensor" means any measurement device that is not part of the vehicle itself but installed to determine parameters other than the concentration of gaseous and particle pollutants and the exhaust mass flow.

              3.2.18. "Set point" means the target value a control system aims to reach.

              3.2.19. "Span" means to adjust an instrument so that it gives a proper response to a calibration standard that represents between 75 per cent and 100 per cent of the maximum value in the instrument range or expected range of use.

              3.2.20. "Span response" means the mean response to a span signal over a time interval of at least 30 seconds.

              3.2.21. "Span response drift" means the difference between the mean response to a span signal and the actual span signal that is measured over a defined time period after an analyser, flow-measuring instrument or sensor has been accurately spanned.

              3.2.22. "Total hydrocarbons" (THC) means the sum of all volatile compounds measurable by a flame ionization detector (FID).

              3.2.23. "Traceable" means the ability to relate a measurement or reading through an unbroken chain of comparisons to a national or international standard.

              3.2.24. "Transformation time" means the time difference between a change of concentration or flow (t0) at the reference point and a system response of 50 per cent of the final reading (t50), as depicted in Figure 2.

              3.2.25. "Type of analyser", also referred to as "analyser type" means a group of analysers produced by the same manufacturer that apply an identical principle to determine the concentration of one specific gaseous component or the number of particles.

              3.2.26. "Type of exhaust mass flow meter" means a group of exhaust mass flow meters produced by the same manufacturer that share a similar tube inner diameter and function on an identical principle to determine the mass flow rate of the exhaust gas.

              3.2.27. "Verification" means the process of evaluating whether the measured or calculated output of an analyser, flow-measuring instrument,