§ 1065.915 PEMS instruments.
(a) Instrument specifications. We recommend that you use PEMS that meet the specifications of subpart C of this part. For unrestricted use of PEMS in a laboratory or similar environment, use a PEMS that meets the same specifications as each lab instrument it replaces. For field testing or for testing with PEMS in a laboratory or similar environment, under the provisions of § 1065.905(b), the specifications in the following table apply instead of the specifications in Table 1 of § 1065.205:
Table 1 of § 1065.915—Recommended Minimum PEMS Measurement Instrument Performance
| Measurement | Measured quantity symbol | Rise time, t10–90, and Fall time, t90–10 | Recording update frequency | Accuracy a | Repeatability a | Noise a |
|---|---|---|---|---|---|---|
| Engine speed transducer | fn | 1 s | 1 Hz means | 5% of pt. or 1% of max | 2% of pt. or 1% of max | 0.5% of max. |
| Engine torque estimator, BSFC (This is a signal from an engine's ECM) | T or BSFC | 1 s | 1 Hz means | 8% of pt. or 5% of max | 2% of pt. or 1% of max | 1% of max. |
| General pressure transducer (not a part of another instrument) | p | 5 s | 1 Hz | 5% of pt. or 5% of max | 2% of pt. or 0.5% of max | 1% of max. |
| Atmospheric pressure meter | patmos | 50 s | 0.1 Hz | 250 Pa | 200 Pa | 100 Pa. |
| General temperature sensor (not a part of another instrument) | T | 5 s | 1 Hz | 1% of pt. K or 5 K | 0.5% of pt. K or 2 K | 0.5% of max 0.5 K. |
| General dewpoint sensor | Tdew | 50 s | 0.1 Hz | 3 K | 1 K | 1 K. |
| Exhaust flow meter | n | 1 s | 1 Hz means | 5% of pt. or 3% of max | 2% of pt | 2% of max. |
| Dilution air, inlet air, exhaust, and sample flow meters | n | 1 s | 1 Hz means | 2.5% of pt. or 1.5% of max | 1.25% of pt. or 0.75% of max | 1% of max. |
| Continuous gas analyzer | x | 5 s | 1 Hz | 4% of pt. or 4% of meas | 2% of pt. or 2% of meas | 1% of max. |
| Gravimetric PM balance | mPM | See § 1065.790 | 0.5 µg | |||
| Inertial PM balance | mPM | 4% of pt. or 4% of meas | 2% of pt. or 2% of meas | 1% of max. |
a Accuracy, repeatability, and noise are all determined with the same collected data, as described in § 1065.305, and based on absolute values. “pt.” refers to the overall flow-weighted mean value expected at the standard; “max.” refers to the peak value expected at the standard over any test interval, not the maximum of the instrument's range; “meas” refers to the actual flow-weighted mean measured over any test interval.