LV and HV status of the RPC system

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

2. Pigi Paolucci - CMS LV review

3. Electronic status HV: 694/696 99%LBB: 384/384 100%LV: 1050/1052 99%T: 401/401 100% • 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 • 2nd generation of insulators (factory) are, until now, stable • 3ndgeneration of insulators (custom) are under design in Napoli • Manpower is ok (3 experts at CERN) Pigi Paolucci - CMS LV review

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 Pigi Paolucci - CMS LV review

5. A3016 behavior cutting the MAO 3Phase

6. LV link board Schema SY1527 • MAO 48 service from BC • Output current = 15-18 A • EASY 3000 – Joint 48 Power & Service • Output power from A3016: • 2.5 Volts / 5.0 Amp • 3.5 Volts / 10.0 Amp 3-phase 48 service MAO 48 power 48 service EASY A3016 Link Box Pigi 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 Pigi 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 Pigi 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 Pigi 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. Vcc = 12 V Vmao = 22 V 6 V Pigi Paolucci - CMS LV review 7/6/10 Pigi Paolucci - INFN 10

11. Mao behavior during 3Phase glitch

12. 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 IntFailstatus is generated by the MAO and the channel goes back to the 48V without any alarm acknowledge. Scope output 40 V MAO A3016 T0 T1 T2 Pigi 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: • Designing a protection on the Link Box LV lines (see tomorrow meeting) • Separating the 48 service and power of the EASY ? OK Under test now Under test now Pigi Paolucci - CMS LV review

14. A3016 firmwarerequirements • 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 Pigi 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 msecand 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. Pigi Paolucci - CMS LV review

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

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

18. Overshot - new A3016 firmware Overshot < 10-15% voltage set Pigi Paolucci - CMS LV review

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

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

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