Title: Immunity to Low Voltage Transients CI265 (including Cranking Waveforms)

Transcription

1 Page: 1 of 7 A INDEX A Index B Scope C Object D Risk Assessment E Review F Related Documents G Requirements and Procedure H Results and Data Generated Z Change History Appendix A Test Set-Up Appendix B Low Voltage Test Equipment Software B SCOPE This document is a supplement to the Ford Motor Company document: Component and Subsystem Electromagnetic Compatibility ES-XW7T-1A278-AC and is applicable only to components intended for use on Jaguar and Land Rover products in the following component categories: Electronic Modules: A, AS, AM, AX, AY Electronic Controlled Electric Motors: EM C OBJECT Components shall be immune to random voltage fluctuations on the power supply lines due to cranking, battery terminal bounce and other momentary loss of supply. D RISK ASSESSMENT A valid risk assessment must be in place before this test is conducted. E REVIEW This document is to be reviewed at least every three years from the date of the last review or update. F RELATED DOCUMENTS Ford Motor Company document: Component and Subsystem Electromagnetic Compatibility ES- XW7T-1A278-AC This document is approved for use by both Jaguar Cars and Land Rover. Prepared by: G J Wilson Authorised by: Gordon Robbins cdsid: GWILS156 cdsid: GROBBIN4

2 Page: 2 of 7 G REQUIREMENTS AND PROCEDURE 1 Purpose The purpose of this test is the verification of the controlled recovery of hardware and software from random power interruptions and voltage dips. There shall be no unintended operation or change in functionality, software lock-up, memory corruption or false Diagnostic Trouble Code (DTC) logging. 2 Any unexplained changes in the content of EEROM shall be recorded, investigated and reported to JLR for approval. Table 1-1 Requirement Application Test Duration Fast Transient Burst Noise (FTBN) Waveform A Random Crank Waveform B Ramp Down/Up Waveform C All Power Supply Circuits All Power Supply Circuits All Power Supply Circuits 12 separate bursts of 5 min. duration 24 hours (8 hours observed, 16 hours unobserved) 1 Functional Performance Status Class A Class B Class C II II II II II II 20 Hours II II II 1 Unobserved for Devices Under Test (DUTs) with memory or functions that can be recorded at the end of the test. FTBN Fig 1-1. FTBN Waveform Parameter Definition T o T 2 T 1 On Off

3 Page: 3 of 7 Key: Switching Parameter Total Test Time Power Supply Voltage T 0 T 1 min =T 2 min T 1 max=t 2 max 1 Resolution Distribution 2 Values 5 min 12 V 60 sec 2 ms 3,6,9,12,18,24,36,48,60,100,200,1000, ms 100 µs preferred, 1 ms max 1/x 2 distribution of pseudo random timing 1 2 For each Tmax value, pseudo random sequences shall be generated using different seed values. The pseudo-random sequences generated must therefore be repeatable. A pre-recorded series of values for each of the 13 tests is available upon request in MS Excel format. See Appendix B for description of 1/x 2 implementation. 3 The test shall be repeated to ensure that each digital input/output is tested in the logic low and logic high condition. 4 Note. The test plan shall state which combinations of input/output conditions are functionally plausible. CRANK WAVEFORM Fig 1-2. Random Crank Waveform B Parameter Definition T 2A IGNITION ON IGNITION OFF U 4 U 3 B U 2 T 9 U 1 0v U 5 U 6 T 3 T 6 T 7 U 4 U 3 C U 2 U 1 0v T 4A U 5 U 6 T 2B U 4 U 3 T 5 D U 2 U 1 0v T 4B U 5 U 6 T 10

4 Page: 4 of 7 Key: Paramete r Min Nom Max Minimum Resolutio n Units Total Steps Comments T 1 N/A T 2A 10 s Can be extended for special requirements where the boot-up time is longer e.g. CD Autochanger. T 2B 5 ms T ms T 4A 1 ms T 4B ms 200 T ms 260 T sec 600 T ms T 8 N/A T 9 N/A This is defined by the time needed for results analysis e.g. DTC read and clear operations. T sec Can be extended for special requirements e.g. Airbag capacitor discharging U V 140 U V 100 U V 80 U 4 12 V U V 20 U V All pseudo random values to be generated using a uniform random distribution. The pseudorandom sequences generated must be repeatable. RAMP WAVEFORM Fig 1-4. Ramp Down/Up Waveform C Parameter Definition T 0 T 1 T 2 T 3 T 4 T 5 U 1 U 2 U 3 0 V U 0

5 Page: 5 of 7 Key: T 0 = 10 s T 5 = 60 s T 1 = 60 s U 0 = 0 V T 2 = 30 s/v (12 V - U 2 ) U 1 = 12 V T 3 = 1 s U 2 = 10 V to 0 V in 0.05 V steps T 4 = 5 s/v (12 V - U 2 ) U 3 = 12 V The module shall be designed to pass the tests in all modes of operation, e.g. on/off, open/closed and shall be tested to verify correct function in each significant mode 6 Test Verification and Test Set-up Waveforms A, B and C shall be generated using the test circuit shown in Appendix A. The test harness connecting the DUT to the Test Fixture and transient pulse generator shall be 2000 mm in length. 7 Test procedures be performed at 20 C ± 5 C. 8 Connect and activate the DUT. Verify that it is functioning correctly. Record any DTC that may be permanently logged. Apply each waveform listed in Table 1-1 to each DUT power circuit for the specified period. H RESULTS AND DATA GENERATED 1 Description of the functions monitored. 2 Unintended operation. 3 Memory corruption. 4 False DTC logging. Z CHANGE HISTORY Issue Date Description of Change 1 18 May 2009 First issue converted to TPJLR format

6 Page: 6 of 7 APPENDIX A Test Set-up: Power Supply Performance Requirements Fig A 2 Power supply rise and fall times T 0 T 2 T 1 12 V 0 V 90% - 10% fall time 600 µs 10% - 90% rise time 600 µs time Fig A 3 Test circuit to validate performance of power supply Power Power Supply and Switching Circuit 5 A load (55 W, 12 V halogen bulb) 2 V 0 No DUT attached 2 Bulb or equivalent load can be integrated into Power Supply and Switching Circuit

7 Page: 7 of 7 APPENDIX B Low Voltage Test Equipment Software The Low Voltage Test equipment shall allow the user to be able to generate a selection of parameterised voltage profiles. The different types of profiles are associated with the different types of tests that will be conducted. These are: 1) Crank Waveform Test 2) Square Wave Test (contact bounce) 3) Ramp Waveform Test DEFINITION OF 1/X 2 DISTRIBUTION The 1/x 2 distribution is designed to ensure that when the pseudo random time parameter values are generated, the majority of the values are skewed to be towards the minimum value. This will maximise the number of test cases for a given duration of testing time. For a given random number x, where 0 x<1, generated with uniform probability the following formula is applied to generate the required parameter values. Note that the required resolution must be taken in to account for the calculation and evidence must be provided to show it is possible to generate all valid parameter values. For a parameter y, -3 2 y = 10 /x where the value of y is rounded down to the nearest resolution step. The resolution must be of maximum step size of 10-3 and preferably Parameter (p) x