The Automotive EMC Laboratory Recognition Program (AEMCLRP) was established in 1998 by the three major automobile manufacturers in the United States, Chrysler LLC (Chrysler), Ford Motor Company (Ford) and General Motors (GM). These companies formed a committee responsible for the definition, documentation and maintenance of a set of EMC tests that an accredited and recognized test laboratory may perform in order to determine the EMC characteristics of automotive components that are integrated in vehicles by the three manufacturers. Since 1998, the AEMCLRP requirements document has been reviewed several times, and revision 4 (with an addendum issued in May 2007), the most current revision, has been used for the past four years. Future revisions are to be expected, due to improvements identified during the assessment process, feedback of laboratories or changes in underlying EMC specifications.
In order for a test laboratory to be recognized by the three manufacturers, a process has to be completed that consists of two major steps. In the first step, the applicant laboratory has to seek accreditation from a recognized accreditation body (e.g., A2LA in the US or JAB in Japan). In order to be accredited, the laboratory must implement and operate a quality system that meets the requirements of ISO 17025-2005. In the technical area, the laboratory will have to identify the specific AEMCLRP tests for which it seeks accreditation. For all the tests, performance history data will have to be submitted prior to the actual on-site assessment for review by the assessor and the AEMCLRP committee. During the on-site assessment, all test methods the laboratory seeks accreditation for are reviewed. This includes an inspection of the actual test setup, verification of suitability of test equipment and the test environment, as well as technical interviews of staff members identified as being competent to perform specific tests. Upon resolution of any deficiencies identified during the on-site assessment, accreditation is granted by the accreditation body. The second step the laboratory has to complete is the performance of proficiency tests for some of the AEMCLRP tests. This involves the testing of an artifact the laboratory is provided with by the committee. This artifact has to be tested in accordance with the related test method, (e.g., Bulk Current Injection – BCI) and the test data has to be submitted to the accreditation body within 1 month after receiving the artifact. The accreditation body will forward the test data to the AEMCLRP committee for a technical review. Based on the review results, the applicant laboratory will be recognized by the individual members of the AEMCLRP committee. It should be noted that the different companies may require the submission of additional documentation before the actual recognition is granted. The representatives of Chrysler, Ford and GM are to be contacted to determine these details.
The AEMCLRP requirements document serves as the basis for both the accreditation and recognition phases. It includes an appendix that defines general requirements a test laboratory has to meet (i.e., Appendix C) as well as separate appendices (i.e., Appendix D though M) for each of the test methods that are part of the AEMCLRP program. The various representatives of Chrysler, Ford and GM on the AEMCLRP committee are responsible for different test methods. The responsible manufacturer is identified as the “Appendix Owner” in each test method appendix. If questions arise about stated requirements, the appendix owner is to be contacted for clarification or guidance. The relevant contact information of each representative is listed on the cover page of the AEMCLRP program document.
This article will discuss the general requirements called out in Appendix C of the AEMCLRP document, as well as the most important details of technical requirements related to the test methods that are most often requested by laboratories for accreditation. An evaluation of these requirements, from an assessment point of view, will also be included to indicate possible areas of the technical review during the on-site assessment. The important requirements related to the quality system that a laboratory has to implement in order to obtain accreditation will not be discussed in this paper.
Generic Requirements (Appendix C)
Appendix C of the AEMCLRP document states generic requirements that do apply to all test methods a laboratory seeks accreditation for. In general, there are three categories of requirements: Clause C.1 summarizes the prerequisites that have to be met before an on-site assessment can be considered. One requirement that is sometimes misunderstood is the necessity to submit written test procedures, per clause C.1.b. In accordance with this requirement, the laboratory has to prepare specific test procedures for each test method. The use of the underlying standard itself is not permissible since standards are often ambiguous, and therefore, require interpretation of details. The purpose of these written test procedures is to ensure the consistent interpretation of these requirements within the laboratory. Furthermore, performance history for each test method, in accordance with section 2.E of each test method annex, is to be submitted to the accreditation body for review. The purpose of this review is the determination of any unusual variances in test results or problems with the test system before the on-site assessment. Confidence has to be established that the test system and procedure that is in place is suitable to demonstrate the proficiency of the laboratory to perform specific tests. This requirement is called out in clause C.1.d. In addition, three different sample test reports of previously completed projects (for each test method) as well as completed test plans will have to be submitted to the accreditation body and to each AEMCLRP committee member company for review prior to the on-site assessment.
Appendix C, clause C.2 defines the method for the determination of the interference threshold. This principle is to be applied to all immunity measurements (e.g., Bulk Current Injection, radiated immunity measurements). It is therefore mandatory for each qualified test engineer to understand and correctly apply this method. A practical demonstration of the application, involving test control software, is usually required to ensure the proper understanding of this principle.
Clause C.3 of Appendix C defines further important requirements for test equipment and the technical management of the applicant laboratory. All test equipment that has an impact on the test result requires calibration. Calibration can be performed by a qualified external calibration laboratory (ideally one that is accredited for the work required to calibrate equipment) or internally. If calibrations are performed internally by the test laboratory itself, it should be noted that this internal calibration group must assume all responsibilities of an external calibration laboratory. There responsibilities include: evidence of traceability to national standards, provision of documented calibration procedures, determination of measurement uncertainty estimates for all parameters calibrated, provision
of an adequate calibration environment (e.g., temperature and humidity controlled facility) and evidence of proper training of internal calibration personnel. Evidence of equipment calibration is to be provided in form of equipment records, specifically calibration certificates.
Other parts of a test system that do not require calibration (e.g., cable insertion loss) need to be verified over a predefined period. This means that the test laboratory must determine an adequate verification period and provide evidence of verification. Furthermore, each piece of equipment must be uniquely identified, per clause C.3.3, to simplify the identification of components if a repetition of tests is required or troubleshooting of the test system is required.
Any testing of devices under the AEMCLRP program requires an approved test plan. The main purpose of such a test plan is to document the testing parameters for the evaluation of an EUT in detail: for example, the acceptance criteria for immunity tests are specified, the exposure levels for immunity tests, the discharge points for ESD testing, the EUT test setup and the description of auxiliary equipment or simulators necessary to put the EUT in an operational state. These test plans have to be approved by a responsible representative of the three manufacturers (i.e., Chrysler, Ford and/or GM) before testing commences. The test laboratory must follow the documented details in the test plan and include relevant details in the final test report.
Clause C.3.6 calls out a requirement for a documented process that is to be followed by the laboratory to determine if auxiliary equipment or simulators are suitable for use in the test setups. This is of particular importance for immunity tests, since the laboratory must ensure that the auxiliary equipment used is working properly when the specified field strength is applied or an interference current is coupled into the test setup. It must be ensured that this auxiliary or monitoring equipment is not affecting the test results in an adverse manner. Similar considerations are to be applied for emissions testing. The emissions emanating from auxiliary or monitoring equipment, if required to be used inside the test environment, must be known and properly identified as such.
Clause C.3 also provides a very important table with applicable tolerances for all quantities, like length, time, voltage, current values and test parameters. These tolerances are applicable unless the test methods call out specific tolerances for a parameter, like for example, the supply voltage tolerance in clause 1.A.7 of Appendix D. The laboratory needs to pay close attention to these tolerances since they will be used during the assessment to determine both the proper test setup and correct performance of the test itself.
Specific Technical Requirements (Appendix D – M)
General Remarks
In this part, requirements are summarized that are common to all test methods in Appendix D through M. For each test method, the laboratory must have the stated reference materials available. These consist of the generic standard(s) listed (e.g., ISO 10605 in Appendix D) as well as the specific manufacturer specifications, which are the internal standards of Chrysler, Ford and GM. If a laboratory seeks accreditation for ESD for example, but only for one or two of the three manufacturers, then only those specifications have to be available that will be accredited. The specific manufacturers are listed on the scope of accreditation of the laboratory that documents the accredited testing capability of the laboratory. It is important for a laboratory to demonstrate how the standards are kept current and how the laboratory keeps current with the developments in the responsible standardization organizations (i.e., ISO, IEC and the three manufacturers).
It is to be noted that the AEMCLRP document may make reference to the manufacturer’s standards that have already been superseded. For example, the current AEMCLRP document Edition 4 (January 26, 2006) references Chrysler document DC-10614 and Ford document ES-XW7T-1A278-AC. These documents have been superseded by Chrysler document CS 11809 (issued on June 4, 2009) and Ford document EMC-CS-2009 (issued on September 30, 2009). All assessments under the AEMCLRP program, however, will be performed against the manufacturer’s specifications that are cited in the AEMCLRP document, until further notice from the manufacturers. Chrysler specifically agreed to have the document DC-11224 (issued in June 2007) to be part of the AEMCLRP document, replacing DC-10614. If a test laboratory seeks accreditation to the manufacturers specifications other than those currently listed in the AEMCLRP document, then the assessment will have to be performed outside the AEMCLRP program, and the listing of these automotive EMC methods on the scope of accreditation will not be under the AEMCLRP program.
For each test method a “Configuration Control List” is to be prepared that itemizes each of the major elements of a test system. This list is used during the assessment to verify the validity of the previously submitted performance history data and to evaluate the capability of performing the actual test method. It is to be noted that if one test method is to be performed in two or more locations (e.g., ESD testing is performed in three different shielded rooms in a laboratory), each test setup requires the preparation of a configuration control list as well as a review during the on-site assessment. The test location in the laboratory will be stated on the scope of accreditation.
The supply voltage for the EUT is to be verified by the laboratory to meet certain values (e.g., 13 V ± 1 V). This verification is to be performed under load conditions, meaning, with the EUT connected and operating as intended. This monitoring is to be performed on an on-going basis while the test is being performed.
Environmental parameters for temperature and humidity have to be determined before testing commences. The laboratory must ensure that the stated ranges for these parameters are met while testing is performed.
ESD Test Procedure – Appendix D
The ESD test procedure is divided into a general part and parts specifically related to the individual manufacturer’s requirements. All manufacturers require that the ESD generator be verified by the laboratory in accordance with
ISO 10605 (2001). Close attention is to be paid to the verification of the RC time constant. This determination is to be made differently for the Ford requirements. Here, the RC time constant is to be determined on the part of the waveform that is exponentially decaying and exposes minimum amount of ringing. The RC time constant requirement, per ISO 10605 clause A.2.3, is to be determined with reference to the second maximum Ip2.
Grounding in general often presents a problem in the laboratory. This applies to the bonding of horizontal coupling planes in case they consist of multiple metal sheets or grounding of horizontal coupling planes (HCP) to a ground plane. In order to ensure repeatable results, adequate grounding is required. One figure of merit is a DC resistance of 2.5 mΩ that can be used to determine the suitability of a bond. Furthermore, an adequate length to width ratio of grounding straps on less than 7:1 (per errata sheet to the AEMCLRP document revision 3) can be selected, with a ratio as low as possible.
The ESD test procedure in accordance with Chrysler specifications is deviating very significantly from the procedure called out in ISO 10605 (2001). For this reason the laboratory must carefully study all details in the Chrysler document to ensure the proper test setup and repeatable performance of the test. For handling tests (un-powered EUT) in accordance with Chrysler specifications, the position of the ESD generator power supply must be more than 50 cm away from the EUT, and the ground reference of the generator must be connected to the HCP at a point 50 cm from the EUT. Furthermore, evidence is to be provided by the laboratory that the ESD generator voltage is verified each time a test series commences. This verification is to be done with an electrometer with an input impedance of greater 1 GΩ. The removal of the charge between two individual discharges is specified in detail and varies somewhat from the approach outlined in ISO 10605 (2001). The charge has to be removed by contacting the bleed-off resistor to the discharge point and the housing of the EUT. Alternatively, a 5 s waiting period between individual discharges has to be implemented in order to sufficiently remove the charges from the EUT.
There are two ESD operating tests described in the Chrysler specifications: the direct coupled and field coupled tests. For the direct coupled test, an ESD simulator, in accordance with IEC 61000-4-2, is to be used (although the latest Chrysler document CS-11809 now references ISO 10605). A specific test fixture is to be provided by the laboratory that meets the requirements called out in clause 10.2.2, Figure 32. Attention is to be paid to the proper grounding of the ESD generator to the defined point at the ESD coupling plane. Furthermore, the EUT grounding and battery grounding points are defined in Figure 32 and grounding is to be implemented accordingly. Finally, the ground plane is required to have a 0.5 m separation from any wall or conductive surface of the test chamber.
The field coupled test requires a discharge network of 330 pF and 330 Ω for testing. It is to be noted further that no discharge is to be applied directly to the harness; discharges have to be applied to the discharge islands of the fixture and only to the parts that are not occupied by the harness. If the test harness is made up of more than 40 lines, the harness bundle shall be flipped over (180 degrees), and the field coupled test is to be repeated.
Conducted Emissions Test Procedure (CISPR 25) – Appendix F
The conducted emissions test procedure, per CISPR 25 (2002), consists of two parts: a voltage measurement using Artificial Networks (ANs) and a current measurement using a current probe. Under the AEMCLRP program only Chrysler requires a current measurement. In general, these measurements have to be made with an EMI receiver that conforms to the specifications in CISPR 16-1-1 (a spectrum analyzer cannot be used for this test). The impedance characteristics of the ANs used have to be verified by providing calibration certificates. Furthermore, the ANs have to be properly bonded to the ground plane by bonding them to the ground plane or providing a very low impedance bond in the form of a strap or even copper tape. The ground plane that is placed on top of a table is to be bonded to the shielded enclosure itself with straps that are no further apart than 30 cm. A sufficient length to width ratio is to be considered for these straps as well (see above).
Clause 1.A.9 of Appendix F states that the measuring cable is to be fed through a bulkhead connector in the shielded room. This clearly indicates that all measuring equipment is to be placed outside the shielded room – not within the measurement environment itself. Furthermore, measurements of the ambient levels have to be made. A test system is deemed suitable for this measurement if the ambient levels are 6 dB or less below the applicable limit (narrowband and broadband). It should be noted that the ambient measurements are to be performed with the same IF bandwidth setting as the actual measurement of the EUT. Only in this case can a proper comparison of the ambient signal levels to the emission limits be made.
The test setup for a specific EUT may involve a second AN, depending on the grounding of the EUT. If the EUT is remotely grounded, (i.e., the ground lead length exceeds 20 cm) then a second AN is to be used, per CISPR 25. The second AN is not necessary if the EUT is locally grounded.
For the current measurement, the current probe has to be positioned at defined locations (50 cm and 100 cm from the EUT connector). It should be noted though that the reference for this distance on the current probe side is not defined. This may cause repeatability issues, especially in the higher frequency range. For that reason, the laboratory should define the reference at the current probe and consistently perform the measurements that way.
Radiated Emissions Test Procedure (CISPR 25) – Appendix G
Radiated emissions measurements have to be performed
inside semi-anechoic chambers. The suitability of these chambers is stated as a requirement of reflectivity in the test area (i.e., the area the EUT is set up in). However, there is no clear guidance as far as the measurement of the reflectivity parameter is concerned. For that reason, the AEMCRP committee decided to accept a chamber if the 3 m NSA data meets the requirements of the theoretical NSA. As an alternative, the chamber manufacturer’s reflectivity specifications for the absorbing material used can be provided as evidence of the suitability of the test chamber. Both alternatives are somewhat questionable from a technical standpoint, since the test distance for radiated emissions measurements is not 3 m but 1 m, and the NSA requirement only covers the frequency range up to 1 GHz. The manufacturer’s reflectivity specifications are usually determined using the assumption of a straight incident wave that travels through the complete depth of the absorbing material. This is obviously the best case scenario and the reflectivity of the absorbing material will assume the lowest numbers. However, at present, the suitability of the semi-anechoic chamber can be validated by the laboratory using these two approaches.
The calibration of antennas is a crucial point that directly affects the measurement results and the repeatability of the measurements. The laboratory must ensure that broadband antennas like biconical, logarithmic-periodic or horn antennas are calibrated in accordance with SAE ARP 958. Any other antenna calibration method will result in different antenna factors that will yield different test results. Evidence of the correctly applied method can be found in antenna calibration certificates that need to clearly state the standard used for the calibration of the antennas. For horn antennas, the reference point for the calibration is to be in the plane of the aperture of the antenna, not the feed point. Rod antennas are to be calibrated using the Equivalent Capacitance Substitution Method (ECSM), per CISPR 25 (2002), Appendix E.
The determination of the antenna height is relative to the height of the setup table – not relative to the floor of the chamber. This specification often leads to deficiencies. For example if the table height is 94 cm (which is within the specified tolerance), then the permissible antenna height range is from 103 to 105 cm. In addition, it is to be ensured that no radiating element of the antenna (in both horizontal and vertical polarization) is closer than 25 cm to the floor and 2 m to the ceiling or the wall of the chamber. Furthermore, the radiating elements must be no closer than 1 m from the absorbing material in the chamber.
Clause 1.A.24 in Appendix G states that the measuring cable is to be fed through a bulkhead connector, meaning that all test equipment is to be placed outside the semi-anechoic chamber. This requirement may lead to the use of preamplifiers, especially for the frequency range above 1 GHz, because of limitations introduced by cable losses and relatively high antenna factors. The laboratory must show that the test system provides enough sensitivity for the measurement by providing noise floor measurements that indicate the noise floor to be at least 6 dB below the applicable limit.
A Ford specific requirement states in clause C.2 that a process for the determination of overload conditions of the test receiver is to be implemented and applied during the test. Despite the fact that the requirement is only applicable when amplifiers are used with a gain of larger than 30 dB, it is good measurement practice to ensure linearity of the receiver and the preamplifier during each measurement. The application of this process is essential in order to avoid erroneous test results.
For measurements according to GM specification GMW 3097, EUTs are to be measured in three orthogonal orientations. The orientations of the EUT for these measurements are to be defined in the approved test plan.
Bulk Current Injection Test Procedure – Appendix I
The setup for BCI test procedure requires insulation of the current probe from the ground plane and positioning of the probe in two or three predetermined locations along the harness. Usually, a fixture is provided by the laboratory, made out of Styrofoam, that allows meeting both the insulation and positioning requirement. The positioning of the probe is referenced to the outermost edge of the EUT connector and not the casing of the EUT. On the current probe side, the distance is to be referenced to the center of the current probe, not the edge closest to the EUT. Furthermore, it is to be observed that the test harness is centered in the current probe itself, which can be achieved by providing slotted Styrofoam pieces that keep the harness centered during the measurements.
The injection current used to perform the test is to be established during a calibration process, involving a test fixture. The control parameter for the actual measurement of the EUT is to be the forward power. This means that the forward power is to be used to adjust the current level for the EUT measurement, such that the predetermined levels of the calibration process can be re-created. The forward power levels have to be established and will be reviewed during the on-site assessment.
In clause 1.D.7, it is stated that measures have to be taken to avoid the coupling of RF energy into the test area. This means that the test equipment is to be placed outside of the testing area.
For measurements in accordance with the GM standard GMW 3097, all simulator equipment is to be placed inside the shielded room along with the EUT. In addition, monitoring equipment must be connected with high impedance connections to avoid an adverse impact on the test results. This is a rather important point to be observed since many proficiency test results are negatively impacted by the use of improper connections of the monitoring equipment. In accordance with GM, Ford and the latest Chrysler specifications, two different types of measurements are to be performed: in the frequency range below 30 MHz, differential mode testing is required. This means that the ground (return) lines are routed outside the current probe. In the frequency range above 30 MHz, these return lines are to be routed through the current probes, along with all other lines of the harness.
Absorber-lined Shielded Enclosure Test Procedure – Appendix K
The laboratory must define which type of test accreditation is sought. The main difference is the use of metallic versus non-metallic bench. The use of the non-metallic bench is only permissible for tests in accordance with Chrysler specifications. Furthermore, the laboratory must state which type of modulations can be applied during the test (i.e., CW, AM and pulse) and which frequency range and field strength levels are available based on the test equipment. These parameters will be stated on the scope of accreditation to correctly reflect the capability of the laboratory.
Radiated immunity tests have to be performed inside semi-anechoic chambers. The suitability of these chambers is stated as a requirement of reflectivity in the test area (i.e., the area the EUT is set up in). However, there is no clear guidance as far as the measurement of the reflectivity parameter is concerned, similar to the situation discussed for radiate emissions measurements in Radiated Emissions Test Procedure (CISPR 25) – Appendix G. For that reason, the AEMCRP committee decided to accept a chamber if the 3 m NSA data meets the requirements of the theoretical NSA. As an alternative the chamber manufacturer’s reflectivity specifications for the absorbing material used, can be provided as evidence of the suitability of the test chamber. The same concerns that were outlined in Radiated Emissions Test Procedure (CISPR 25) – Appendix G apply to this approach.
The E-field probes used to establish the test field strengths during a calibration process must meet a stated isotropicity specification. Evidence can be provided through manufacturer’s specifications and subsequently by providing calibration certificates that include a calibration of the probe for isotropicity. It should be observed that the manufacturer’s approach for the calibration of the isotropicity is to be used during subsequent calibrations. This includes the knowledge of the frequency and orientation of the probe for this part of the probe calibration.
In clause 1.A.14, it is stated that the cable that connects the signal generation system to the antenna is to be fed through a bulkhead connector. This again requires that the test equipment is to be placed outside the test area. Any deviation the laboratory tries to implement (for example, placing amplifiers close to the antenna inside the chamber) is to be approved by the AEMCLRP committee. The assessor will have to cite a deficiency if equipment is placed inside the chamber, but upon approval of the AEMCLRP, this deficiency will be considered addressed.
For testing with a metallic bench, it is to be ensured that the closest antenna element is located more than 25 cm from the floor for both polarizations and more than 150 cm from the walls and ceiling of the shielded room. Based on the antenna type used, this will require a certain minimum size for the shielded room. A calibration process using calibrated E-field probes is to be performed to establish the power levels necessary in order to achieve the stated E-fields for EUT testing. The control parameter to be used for adjustment of the levels during the EUT test is the forward power.
For testing with a non-metallic bench in accordance with Chrysler specifications, the calibration process is similar to the one defined in IEC 61000-4-3. A uniform E-field plane is to be established, and this is positioned in the location the harness is to be placed. For this type of test, the EUT is to be placed on a bench made from Styrofoam (or another material with a low permittivity). In addition, the EUT is to be tested in three orthogonal planes that are to be defined in the approved test plan. Lastly, the laboratory must provide a fixture so that the E-field probes can be positioned in a repeatable manner during the calibration process. This is also a requirement for metallic bench testing in accordance with clause 1.C.7 (testing in accordance with Ford standard ES-XW7T-1A278-AC). This will greatly enhance the repeatability between calibration processes.
In addition, for Ford specific tests, the laboratory must determine the harmonic content of the test signal at the output of the power amplifier. This test is to be performed at the frequency which requires the highest input level to the power amplifier. The calibration files have to be evaluated in order to determine this frequency, and the input power level to the amplifier has to be selected when performing this measurement. The stated requirement of 20 dBc for the harmonics has to be met at this frequency.
An additional requirement based on the antenna aperture is documented in clause 1.D.11 for GM specific tests in accordance with GMW 3097. The antenna used for testing has to be selected such that the aperture of a horn antenna, or in an approximation, the length of the largest radiating elements of a logarithmic-periodic antenna, will meet the stated far field condition of (2*d2)/λ. The laboratory must investigate if the antenna used for radiated immunity testing meets this requirement. If deviations are considered, the AEMCLRP committee will have to specifically approve the use of antennas that do not meet this requirement.
Absorber-lined Shielded Enclosure Radar Test Procedure – Appendix M
An addition to the radiated immunity procedure described in Appendix K is the procedure for radiated immunity testing where radar pulses are simulated. These tests are only applicable to Ford and GM specific tests (although Chrysler also utilizes radar pulse modulation in their specifications). The laboratory must perform a field characterization, per clause 1.C.5, utilizing a horn antenna pulsed amplifier. This verification method requires use of one of a predefined group of receiving antennas. If another antenna is to be used, specific approval of the AEMCLRP committee is to be obtained. The following additional requirements will have to be met during testing for the verification of the pulsed E-field:
a) The phase center of the antenna is positioned 125 mm above the surface of the dielectric support used during actual testing
b) Forward Power shall be the reference parameter for characterization of the field
c) Calibration at lower field strengths with subsequent power scaling for higher field strengths is not permitted
d) Pulse modulation characteristics shall conform to that illustrated in Figure 4. The maximum RMS forward power (Ppulse) used for pulsed modulation testing, shall be the same as the CW calibration power (PCW_CAL) (i.e. PPULSE = PCW_CAL).
Summary
The AEMCLRP program provides a comprehensive set of quality-related and technical requirements for the accreditation and recognition of EMC test laboratories. For a test laboratory to successfully complete the accreditation and recognition steps of the overall process, the applicable manufacturer’s specifications and underlying automotive ISO standards are to be studied in detail, and the implementation of these requirements are to be checked. Hands-on testing experience is necessary in order to successfully demonstrate proficiency of performing the tests the laboratory seeks accreditation for. In addition, the preparation of performance history for tests will help demonstrate the repeatability of the test equipment and parts of the test setup and test environment. All these elements will be evaluated by the assessor during the on-site assessment. If the laboratory has reasons for deviating from stated requirements, the assessor will have to cite a deficiency if no written approval from the AEMCLRP committee is available. This approach ensures that deviations are directly approved by the AEMCLRP committee and are therefore consistent and not dependent on the assessor. This type of approval by the AEMCLRP committee can be sought by the laboratory before the on-site assessment to avoid cited deficiencies or after the on-site assessment as a response to documented deficiencies. 
Acknowledgements
The author would like to thank Mrs. Tori Barling for proof reading this article and Mr. Robert Kado of Chrysler LLC for the technical review.
Werner Schaefer is a compliance quality manager and technical leader for EMC and RF/uwave calibrations at Corporate Compliance Center of Cisco Systems in San Jose, CA. He has 25 years of EMC experience, including EMI test system and software design, EMI test method development and EMI standards development. He is the chairman of CISPR/A/WG1 and a member of CISPR/A/WG2 and CISPR/B/WG1. He also is the US Technical Advisor to CISPR/A and a member of ANSI C63, SC1/3/5/6/8, and serves as an A2LA and NVLAP lead assessor for EMI and wireless testing, software and protocol testing and RF/microwave calibration laboratories. He also serves as an ANSI representative to ISO CASCO, responsible for quality standards like ISO 17025 and ISO 17043. He is a member of the Board of Directors of the IEEE EMC Society.
He was actively involved in the development of the new standard ANSI C63.10 and the latest revision of ANSI C63.4, mainly focusing on test equipment specifications, use of spectrum analyzers and site validation procedures.
Werner Schaefer is also a RAB certified quality systems lead auditor, and a NARTE certified EMC engineer.
He published over 50 papers on EMC, RF/uwave and quality assurance topics, conducted numerous trainings and workshops on these topics and co-authored a book on RF/uwave measurements in Germany.
