8-May-2010 LV Workshop1 Alignment LV: quick’n dirty HW review Alignment uses CAEN low voltage –No HV –Low power consumption electronics: under kW per crate 1xSY1527LC MainFrame and 2xA1676A + 1 spare branch controllers –In S4F03 2xA spare 48 V AC/DC converters and 2xEasy3000 Crates + 2 spares –In YE±1 28xA3006 LVPS + 3 spares –In YE±1 alignment EasyCrates –In YB±2, YB0 DT EasyCrates We use DT AC/DC, MF and Branch Controllers

8-May-2010 LV Workshop2 LV for Alignment: issues Currently: –1 failure during operation A3006 (sn47) in CMS buffer zone needs repair –Failures of MAB Custom Boards LV related? Not sure, under investigation. Maybe ramp-up voltage “sticks” for a while on a V, CB boot loader goes mad and tries to rewrite the CB firmware. This has been corrected on 30 CBs (except on positive side of YB0 where the last problem has happened two weeks ago. All other CBs work well) In the past: –10 A3006 modules have needed some repair That’s 10 out of 30 !! A3006s are “new” designs Much more stable during last 12 months (only 1 failure)

8-May-2010 LV Workshop3 LV for Alignment: CAEN support All repairs have been through CERN Pool BEFORE CMS buffer zone –10 modules sent for repair –Turn-around time ~2 months –Two modules needed a second CAEN repair –Availability was good –We expect a continued maintenance support Now –1 module in CMS buffer zone –CAEN availability and turn around time not expected to change –Not enough experience yet

8-May-2010 LV Workshop4 LV for Alignment: Anderson connectors PP75 connectors only in the 2 AC/DCs –We do not regularly monitor the temperature But it is displayed PVSS LV project –We do not have retaining brackets (I think) –We have not changed to flexible cables as far as I know LVPS use PP15 connectors –Channel temperatures can be read in PVSS LV project –Connectors have a screw-based retainer Fuses –None directly fed by MAOs –All inside electronic boards Turn-off issues –None –If service power fails, our modules go off

8-May-2010 LV Workshop5 LV for Alignment: resources LV system –Xiaofeng Yang: endcap –Noemi Beni/Zoltan Szillasi: barrel –Javier Gonzalez: link and general HV system –does not apply Interface with DCS –Javier Gonzalez: main interface –Xiaofeng/Noemi: occasional contact Away from CERN: –Javier Gonzalez is based at IFCA, Spain

8-May-2010 LV Workshop6 LV for Alignment: maintenance Repairs –Done by CAEN through CERN POOL Records –Kept by Gervasio Gómez in an excel spread sheet Which is kept updated and put online –This is our repair history as well Tests –Performed at alignment LV rack in Bât. 904 –Test results also recorded

8-May-2010 LV Workshop7 LV for Alignment: interlocks Link –Power cards at each crate provides interface between CAEN LVPS and electronics –Additional fuse protection at each electronic card –Expert: Antonio Molinero (CIEMAT, Madrid) Endcap –No interlocks –Fuse protection of all electronic boards But most are hard to access in case of failure –Expert: Xiaofeng Yang (at CERN) Barrel –No interlocks –Expert: Zoltan Szillasi (at CERN)