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A3016 and MAO test at CAEN

A3016 and MAO test at CAEN

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A3016 and MAO test at CAEN

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  1. A3016 and MAO test at CAEN Pigi, A. Boaino & CAEN

  2. Test Schema • MAO 48 service from BC • EASY 3000 – Joint 48 Power & Service • Dummy LinkBoard load: R & C • Output power from A3016: • 2.5 Volts / 5.0 Amp • 3.5 Volts / 10.0 Amp • MAO output current = 5 A • With a A3009 board more = 17 A SY1527 3-phase 48 service MAO 48 power 48 service EASY A3016 load

  3. What powering OFF the MAO in the proper ways ? • Powering OFF the MAO via SY1527 or using the interlock placed on the front

  4. What powering OFF the EASY in a “bad” way ? • Powering OFF the EASY 3000 crate removing the power or service connector from the back

  5. 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

  6. What happen cutting MAO 3-phase ? • MAO goes OFF in 2 steps: a first from 48 Vto 22 V and a second from 22 V to 0 V (slower) • A3016 channels are switched OFF in 200 msec after 600 msecfrom the MAO shut-down (software delay to be sure that was not a voltage oscillation) 48 V A3016 switched OFF 2.5 V Step #1 Step #2

  7. When and why the oscillation is generated cutting the MAO 3-phase ? • The oscillation on the A3016 output is generated when the MOA output cross 22 Volts • An oscillation has been seen when Vcc goes from 12 V to 6 V and this produce the spike. Vcc = 12 V Vmao = 22 V 6 V

  8. How prevent this spike during a MAO power-cut ? • We can prevent the oscillation and spike separating the 48 service and power of the EASY crate as suggested by the CAEN since long time. • To do that we need to modifying the cable routing and have a dedicated MAO under UPS to generate the 48 service. • A faster solution is the put a “big” capacitor between the 48 power and service in order to give a couple of second more to the service and let the EASY crate switching off in the proper way. • A capacitor of 33 mF + a protection diode are ok

  9. Results with C and diode service power 1.5 sec

  10. Results with C and diode No spikes or oscillations 48 V 600 msec 2.5 V

  11. Conclusion on the MAO • MAO cannot reboot itself even in case of “bad” shut-down. • Need to clear the status alarm to switch back it. • In case of SY1527 reboot the MAO and the LV channels stay OFF until a “clear alarm” • CAEN recommends to use 2 different lines for the power and service of the EASY crates.

  12. Conclusion on the A3016 • The LV board has been designed as a general purpose board, for ALICE, ATLAS and CMS • The output feedback circuit has not been optimized to supply the link board (one crate has a large input capacitance) • Let me remember you that Link Baord does not have any regulator or protection on the power lines to reduce the power dissipation. • Oscillations have been detected during the switching ON of the channels and have been partially cured via firmware  we still need to work on that and on the 2 channels sync. • An oscillation has been detected, during the last week test at CAEN, on the A3016 channels in case of improper shut-down of the MAO (3-phase cut) • Can this oscillation break the Link Board ? • How can we can solve this problem and all the other possible problems ?

  13. Conclusion on the A3016 Long Term Solutions: • Designing a protection on the LB crate LV lines • Designing a “special” output feedback circuit of the A3016 for the link board Temporary Solutions: • Working on the firmware in order to reduce problem during the switching ON • Synchronize the switching ON of the 2 independent channels via firmware (now is via PVSS) • Separating the 48 service and power of the EASY • OR • Introducing a big capacitor (33 mF) between the service and power line of the EASY: • Solution has been successfully tested at CAEN • It does not have any side effect on the system

  14. Action Items • Capacitor test at 904 and eventual installation • Definition of the synchronization requirements and ramping-up sequence. • two channels at same time ? How many steps ? How long the sequence ? • Official request at CAEN of a new “firmware” to develop and test asap and CMS validation. • Design of the LV lines protections