Electromagnetic Compatibility Test for CMS Experiment.

1. Authors C. Rivetta– Fermilab F. Arteche , F. Szoncso, - CERN Electromagnetic Compatibility Test for CMS Experiment.

2. OUTLINE • 1.Introduction • 2. Common Impedance • LISN. • CDNs. • 3.Emission Test • Harmonics. • RF conducted emission test. • 4.Immunity Test • RF conducted noise immunity test. • Slow transients - Surge immunity test. • Fast transients - Burst immunity test. • Voltage dips and short voltage interruptions immunity test • 5.Conclusions 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

3. 1.INTRODUCTION • EMC phenomena are present in CMS • Noise generated by DC-DC converters • Common mode & Differential mode • Transients • Over-voltages • Induced via magnetic fields • Load changes • Switching • Voltage variations • Harmonics • It is important to measure & control them • Goal of these tests • Get the levels of “emission” and “immunity” • Identify possible EMC problems. 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

4. 1.INTRODUCTION • Generic, Basic and military Standards & Aerospace rules. • There are a lot of standards • For practical reasons “ we only consider some of them “ • Emissions test • RF conducted noise(based EN-55011-22 // MIL-STD-461// IEEE Std 1515) • CM & DM ( high and low frequency) • Harmonics (based EN- 61000-3) • Special for 400 Hz power supply distribution system (very low) • Immunity test • Immunity to RF conducted noise (based EN-61000-4-6) • Electrical fast transient burst immunity test (based EN-61000-4-4). • Surge immunity test- Over-voltage (based EN-61000-4-5). • Voltage dips, short interruptions and voltage variations immunity test (based EN-61000-4-11). 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

5. 2. COMMON IMPEDANCE LISN & CDNs • Two kinds of common impedance • Line Impedance Stabilisation Network (LISN) • Coupling De-coupling Network (CDNs) CDNs • Protect auxiliary equipment • Values specified by the standards LISN • Present stable a well defined impedance • Standardise the measurements of test • Values estimated from power cables • HF - Characteristic Impedance (CM & DM ) • Different from commercial LISN • Couple EUT - Measuring equipment. • Standardise the measurement to 50 Ohms 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

6. 2. COMMON IMPEDANCE LISN & CDNs • LISN HCAL Sub-System Zcm =13 Ohms Zdm =42 Ohms 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

7. Measurement equipment Zm LISN EUT 3.EMISION TEST - Harmonics • Effects by pulling the current from power main for only a part of the cycle • Typically rectifiers ( we have 400 Hz power distribution) • Implications • Quality power distribution. • Power supply distribution over-design • Power transformers over-stress • Equipment overheat • Oriented to the 400 Hz PS distribution • AC-Dc converters • Transformers • Limits of harmonics based on international standards & studies. Power supply unit 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

8. 3.EMISION TEST - RF conducted noise • Goal of test control the conducted emission level • Power Supplies & FEE • Frequency Range 9 kHz - 50 MHz • Conducted emissions – Propagation • Common Mode • Group of conductors and ground or other conductors. • Differential Mode • Conductor pairs (Negative-Positive or Phase-Neutral) • Abundant energy exchange between modes CM - DM conversion • System topology as close as possible to final one • Common impedance LISN • Equipment used • Current probes & Spectrum Analyser 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

9. 3.EMISION TEST - RF conducted noise • Power Supply • FEE 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

10. 4.EMISION TEST - RF conducted noise EN-55022 • Test Results Power Supplies • Input • Results refereed to 50 Ohm to compare them with the standards • We used EN - 55022 B • Output • There is no standards so we need to generate them • From this values and the values from Immunity test • FEE • Input • Results refereed to 50 Ohm to compare them with the standards 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

11. 4.IMMUNITY TEST- RF conducted noise • Electromagnetic immunity is the ability,of a device equipment or system to perform without degradation in presence of electromagnetic disturbances • Goal of these tests • Immunity level of FEE and PS to conducted disturbances. • Injection of conducted noise to the FEE • Common impedance - LISN • The idea is inject signal and measurepedestal • Identify frequency areas where the pedestal is not valid • This test will define sensible areas of the FEE • Injection via current probes • It is recommended to Voltage & Current 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

12. Voltage DM measurement LISN Current DM measurement LISN Injection of CM current Voltage DM measurement Current CM measurement LISN Voltage CM measurement 4.IMMUNITY TEST - RF conducted noise • Three different set-ups • DM configuration • 9 kHz / 14 kHz up to 100 MHz • CM at HF configuration • 10 kHz up to 100 MHz • CM at LF configuration • (A few hertz up to 10 kHz) • The value of the amplitude of the signal depends on the sensitivity of the FEE. • This test is complementary of Conducted emission TEST 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

13. 4.IMMUNITY TEST - RF conducted noise - Example I1 • CM ICM 12.05 µA 12 V 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

14. 4.IMMUNITY TEST - RF conducted noise - Example • CM • I1 0.41mA IDM ICM 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

15. 4.IMMUNITY TEST - Surge immunity Test • The goal of test - Determinate the equipment susceptibility to damage by over-voltage generated by • Load changes /Short Circuits /Faults to earth • Common Impedance LISN & CDNs to protect auxiliary equipment • Coupling network will be used to inject the transient • 9 µf & 10 Ohms or 18 µf - Depends on the Test • Pulse Characteristic • Voltage O.Circuit 1.2/50 µs. • Current S.Circuit 8/20 µs • A Zenner / Trans-absorb protect EUT from this emission 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

16. 4.IMMUNITY TEST - Surge immunity Test • The amplitude of the signal • Standards • Electrical environment • 5 Different Class • 0.5 , 1kV , 2 kV, 4 kV • For CMS values • Counting Room - Detector • Class 3 or 4 - (1kV-4 kV) • Balconies - Detector • Not clear • Test simulation for 3 different amplitudes • 1 kV , 500 V , 100 V • Line - Line Trans-absorb Filter FEE CDNs 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

17. 4.IMMUNITY TEST - Surge immunity Test 83 V • It is difficult to find a device to dissipate this power and clamp the voltage within maximum values valid for the FEE. • Level selection • High level • Increase cost or could not have any technical solution • Low level • Increase risk of failure by over-voltage • Final selection based on: • Preliminary studies • Reliability. • Cost • Risk 45 V 15 V 17 kW 4.5 kW 0.3 kW 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

18. 4.IMMUNITY TEST - Burst immunity Test • The goal of test • Fix the susceptibility to damage by over-voltage generated by switching transients. • Common Impedance LISN & CDNs to protect auxiliary equipment. • Coupling network will be used to inject the fast transient - 33 nf. • Pulse Characteristic • Double exponential 5ns/50 ns. • Burst duration ~ 15 ms / 300 ms (1 minute). • Spectra content of signal HF. • Layout very important. • Coupling of burst depends strongly from parasitic capacitance. 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

19. 14 V 9 V 8.5 V 4.IMMUNITY TEST - Burst immunity Test • Class is not defined yet. • Not very important • A simple Capacitor protects to FEE from this emission • Test simulation • 3 different RF capacitors • 5nf, 500nf, 1000nf • Line - Ground • Amplitude • Class 3 - 2 KV. 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

20. 4.IMMUNITY TEST - Voltage dips immunity Test • Noise source • Faults in the networks • Sudden large change of load • Test on FEE • Short interruptions & Voltage variations • Test on Power Supplies • Short interruptions & Voltage variations • Voltage dips • Common impedance LISN • Test level • Standards • Voltage dips • ( 0-40-70%) V nominal - Voltage variations • (0 -40 % ) V nominal. - • For us under study 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002

21. 5. CONCLUSIONS • EMC phenomena is present in CMS • It is important to measure and control them • EMC tests are based on standards and aerospace industry . • EMC test will be focus on conducted noise • Immunity and emissions test • Only a few test will be considered dueto practical reasons • Test levels has not fixed yet • It has a big influence in the elections of filters & protections • It will depend on • Technical studies • Reliability • Cost • Risk 8th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002