1. LV and HV status of the RPC system RPC detector and trigger group

2. Equipment type Totalinstalled spare % of spare SY1527 54125,0% A3485 53266,7% A3512NHV127116119,5% A1676BC A16762017317,6% EASY3000SCRATE403825,3% EASY3000CRATE4439512,8% A3000FBFAN2723417,4% A3486S_380MAO AC/DC1210220,0% A3009LV DC/DC1059699,4% A3801ATemperature AC/DC1714321,4% RPC HV distributor BarrelHV Distribution Box373525,7% A3486S_230 EndcapMAO AC/DC131218,3% RPC HV distributor EndcapHV Distribution Box24 00,0% A3016LV DC/DC686446,3% RPC LinkBoardBoxLBB1059699,4% RPC MasterBoardMLB3513004916,3% RPC SlaveBoardSLB5745007014,0% RPC ControlBoardCB12412043,3% RPC LB FrontPanelLB FP12512054,2% RPC OptoBoxOB1410440,0% 7/6/10Pigi Paolucci - CMS LV review2

3. Electronic status HV:694/69699% LBB: 384/384100% LV: 1050/1052 99% T: 401/401100% LV detector system is working smoothly. HV system: – 3 boards are under investigation at CAEN – Few coaxial connectors replaced – well know insulator Problem appears very often after SY1527 kill/power cut 2 nd generation of insulators (factory) are, until now, stable 3 nd generation of insulators (custom) are under design in Napoli Manpower is ok (3 experts at CERN) 7/6/10Pigi Paolucci - CMS LV review3

4. Low Voltage Link Board status After many failures in the link board system the RPC-Trigger community decided to investigate all the possible causes analyzing not only the LB system but also the LV system: A3016 boards MAO LV and MAO power cut and power cycle Power off and on of the link box CAEN firmware 7/6/104Pigi Paolucci - CMS LV review

5. A3016 behavior cutting the MAO 3Phase

6. LV link board Schema 1.MAO 48 service from BC – Output current = 15-18 A 2.EASY 3000 – Joint 48 Power & Service 3.Output power from A3016: – 2.5 Volts / 5.0 Amp – 3.5 Volts / 10.0 Amp MAO SY1527 48 service 3-phase EASY A301 6 48 service 48 power Link Box 7/6/106Pigi Paolucci - CMS LV review

7. What powering OFF the MAO in the proper ways ? Powering OFF the MAO via SY1527 or using the interlock placed on the front OK 7/6/107Pigi Paolucci - CMS LV review

8. What powering OFF the EASY in a “bad” way ? Powering OFF the EASY 3000 crate removing the power or service connector from the back OK 7/6/108Pigi Paolucci - CMS LV review

9. What cutting the MAO 3-phase ? Shutting-down the MAO cutting 3-phase oscillation does not depend from the MAO load (from 4 A to 18 A) sometimes 2 oscillations in few msec oscillation disappear separating the 48 power from the 48 service No other ways to reproduce it NOT OK 7/6/109Pigi Paolucci - CMS LV review

10. What happen cutting MAO 3-phase ? MAO goes OFF in 2 steps: from 48 to 22 V and a from 22 to 0 V The A3016 channels go off when MAO voltage is around 22 V and this takes about 250-300 msec (fixed load on the MAO) Around 22 V the boards begin to work not properly (Vcc goes from 12 V to 6 V) and generates oscillations on Vout. 7/6/1010Pigi Paolucci - CMS LV review Vmao = 22 V Vcc = 12 V 6 V 7/6/1010Pigi Paolucci - INFN

11. Mao behavior during 3Phase glitch

12. T0T1 At T0: Turn off the 3-phase switch MAO starts ramping down with a “dummy load” - NO status changing After a while, it gives UNV status, but the channel keeps status ON. At T1: MAO ramps down with different slope (real load) At T2: MAO swiched ON (600 ms from T0). Switching OFF-ON in <1sec, no IntFail status is generated by the MAO and the channel goes back to the 48V without any alarm acknowledge. T2 Scope output MAO A3016 40 V 7/6/1012Pigi Paolucci - CMS LV review

13. What we have done ! Already implemented Solutions: Introducing a big capacitor (33 mF) between the service and power line of the EASY Improve the A3016 firmware Modify the MAO firmware Long Term Solutions: 1.Designing a protection on the Link Box LV lines (see tomorrow meeting) 2.Separating the 48 service and power of the EASY ? 7/6/1013Pigi Paolucci - CMS LV review OK Under test now

14. A3016 firmware requirements Couple of channels in tracking mode (ON/OFF/Trip at same time and with one command). – delay between the 2 channels must be less than 1 msec Ramping up in stepping mode: – overshoot first steps < 10% of the setting voltage – overshoot of the last step must be < setting voltage – voltage must be always < setting voltage (no overshoot above max value) – Over-voltages are very dangerous for the LB. – no under-voltage dips are allowed after VCC2.5 gets above 2.0 V – no under-voltage dips are allowed after VCC3.3 gets above 1.2 V – total time to reach the setting voltages (3.5 V and 2.5 V) should be less than 60 msec 7/6/1014Pigi Paolucci - CMS LV review

15. MAO firmware requirements The MAO behavior is case of glitch on the 3- phase line is potentially dangerous for the LV system. Turn OFF the MAO when the Vmon < 43-40 Volts in about 100 msec and require an acknowledge afterwards to bring the channel back to ON. – In 100 msec firmware measures the voltage 5 times, should be enough. – After 100 msec the MAO voltage is around 35-38 V and it is enough to shut-down properly the A3016. 7/6/1015Pigi Paolucci - CMS LV review

16. 7/6/10Pigi Paolucci - CMS LV review16 MAO Vcc Vout New MAO firmware old MAO firmware Oscillations on both Vcc and Vout 200 msec OFF – 38V 43V New MOA firmware

17. 7/6/10Pigi Paolucci - CMS LV review17 Rumping up - new A3016 firmware 50 msec 80 msec 2.5 V 3.5 V No overshot over the max voltage

18. 7/6/10Pigi Paolucci - CMS LV review18 Overshot - new A3016 firmware Overshot < 10-15% voltage set

19. 7/6/10Pigi Paolucci - CMS LV review19 Channels delay- new A3016 firmware 2 msec Delay stable and < 2 msec (depends on the charge)

20. Results with C and diode power service 1.5 sec 7/6/1020Pigi Paolucci - CMS LV review

21. Results with C and diode 2.5 V 48 V No spikes or oscillations 600 msec 7/6/1021Pigi Paolucci - CMS LV review

22. Conclusions Running systems is very stable Spares are under control (> 5%) Many improvements done on the trigger LV system to assure a more stable and safe behaviors of the Link System Hardware protection of the Link Box is under test (Warsaw group) 7/6/10Pigi Paolucci - CMS LV review22