Skip to main content
Find a Lawyer

Code of Federal Regulations Title 40. Protection of Environment § 40.1066.125 Data updating, recording, and control

Current as of January 02, 2025 | Updated by Findlaw Staff

This section specifies criteria that your test system must meet for updating and recording data. It also specifies criteria for controlling the systems related to driver demand, the dynamometer, sampling equipment, and measurement instruments.

(a) Read and record values and calculate mean values relative to a specified frequency as follows:

(1) This paragraph (a)(1) applies where we specify a minimum command and control frequency that is greater than the minimum recording frequency, such as for sample flow rates from a CVS that does not have a heat exchanger. For these measurements, the rate at which you read and interpret the signal must be at least as frequent as the minimum command and control frequency. You may record values at the same frequency, or you may record them as mean values, as long as the frequency of the mean values meets the minimum recording frequency. You must use all read values, either by recording them or using them to calculate mean values. For example, if your system reads and controls the sample flow rate at 10 Hz, you may record these values at 10 Hz, record them at 5 Hz by averaging pairs of consecutive points together, or record them at 1 Hz by averaging ten consecutive points together.

(2) For all other measured values covered by this section, you may record the values instantaneously or as mean values, consistent with good engineering judgment.

(3) You may not use rolling averages of measured values where a given measured value is included in more than one recorded mean value.

(b) Use data acquisition and control systems that can command, control, and record at the following minimum frequencies:

Table 1 of § 1066.125—Data Recording and Control Minimum Frequencies

Applicable section

Measured values

Minimum command and control frequency a

Minimum recording frequency b, c

§ 1066.310

Vehicle speed

10 Hz.

§ 1066.315

§ 1066.425

Continuous concentrations of raw or dilute analyzers

1 Hz.

§ 1066.425

Power analyzer

1 Hz.

§ 1066.501

§ 1066.425

Bag concentrations of raw or dilute analyzers

1 mean value per test interval.

40 CFR 1065.545

Diluted exhaust flow rate from a CVS with a heat exchanger upstream of the flow measurement

1 Hz.

§ 1066.425

40 CFR 1065.545

Diluted exhaust flow rate from a CVS without a heat exchanger upstream of the flow measurement

5 Hz

1 Hz means.

§ 1066.425

40 CFR 1065.545

Dilution air flow if actively controlled (for example, a partial-flow PM sampling system) d

5 Hz

1 Hz means.

§ 1066.425

40 CFR 1065.545

Sample flow from a CVS that has a heat exchanger

1 Hz

1 Hz.

§ 1066.425

40 CFR 1065.545

Sample flow from a CVS that does not have a heat exchanger

5 Hz

1 Hz means.

§ 1066.425

§ 1066.420

Ambient temperature

1 Hz.e

§ 1066.420

Ambient humidity

1 Hz.e

§ 1066.420

Heated sample system temperatures, including PM filter face

1 Hz.

a CFVs that are not using active control are exempt from meeting this requirement due to their operating principle.

b 1 Hz means are data reported from the instrument at a higher frequency, but recorded as a series of 1 s mean values at a rate of 1 Hz.

c For CFVs in a CVS, the minimum recording frequency is 1 Hz. For CFVs used to control sampling from a CFV CVS, the minimum recording frequency is not applicable.

d This is not applicable to CVS dilution air.

e Unless specified elsewhere in this part or the standard-setting part. Note that this provision does not apply to soak periods where recording frequencies are not specified. For these instances, we recommend a recording frequency of ≥ 0.016 Hz.

Previous Part of Code Next Part of Code
Back to Chapter List

Cite this article: FindLaw.com - Code of Federal Regulations Title 40. Protection of Environment § 40.1066.125 Data updating, recording, and control - last updated January 02, 2025 | https://codes.findlaw.com/cfr/title-40-protection-of-environment/cfr-sect-40-1066-125/

FindLaw Codes may not reflect the most recent version of the law in your jurisdiction. Please verify the status of the code you are researching with the state legislature before relying on it for your legal needs.

Was this helpful?

Welcome to FindLaw's Cases & Codes

A free source of state and federal court opinions, state laws, and the United States Code. For more information about the legal concepts addressed by these cases and statutes, visit FindLaw’s Learn About the Law.

Go to Learn About the Law

Latest Blog Posts

For Legal Professionals

Learn About The Law

Get help with your legal needs

FindLaw’s Learn About the Law features thousands of informational articles to help you understand your options. And if you’re ready to hire an attorney, find one in your area who can help.

Go to Learn About the Law

Need to Find an Attorney?

Search our directory by legal issue

Enter information in one or both fields (Required)

Copied to clipboard