LV-workshop during CMS Electronics week During a recent Workshop, Sergei Lusin reported that in CMS was observed an OVERHEATING IN SEVERAL POWER CONNECTORS. This is a potential “Fire hazard” that affect all Subdetectors using Power Supplys which use the 55A “powerclaw contact” Specifically the CAEN A3486 – (MAO) 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 1

Short and Long term suggestion plans It was generally agreed upon that something needed to be done to allow long term lifetime of the system. Short term plan Use softer cables less capable of transferring twist, (which does not involve extensive recabling) Followed by the addition of a screwed bracket. Option Voltage drop measurement between MAO and Easy Crates by installation of sense wires. ( The option will be tested by the HCAL) Long term plan The ultimate solution will require the modification of the connector assemblies on the power supplies, which will involve discussions with the vendor, and the development of a retrofit plan. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 2

Partial recabling on PIXELs racks X2F36/X2F37 Power Supplies cables replacement made at P5 (17February2010) Following the “Short term solution” we decided the replacement of the short cables links between the AC-DC Converters (MAOs) and the Easy crates 4000, using more flexible cables. More in details for each racks we introduced two new short extensions related to the upper MAO, and we replaced three other extensions related to others MAOs. This will allow the spring mechanism inside the connectors shells to align the contacts properly. Again, to prevent any progressive “walking – out” of the plug connectors we added a screwed bracket between the cable connectors and the panel. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 3

LV- workshop during CMS electronics week General discussion ......& answers Do you have in-line fuses on the service Power Connections that are fed directly by MAOs? .......................................................................YES Have you observed any strange turn-off issues of the DC outputs In the event of interruption of primary or service power?.............................ANY How do you fix bad modules (LV, HV, any others) ?...............Via a Pixels support activities performed at TIF, & via CERN pool. How do you keep records?.......................................................Via elogs- etc. Remarks: To control all the devices used at P5 has been created a link on TWIKI twiki.cern.ch/twiki/bin/view/CMS/PixelCaenSpareComponents with an UPDATE MAP of the Power System Parts installed. You can find also a MAP of the DEVICES out of the system......(spare parts) 8/06/2010 Pasquale D’Angelo – INFN Milano Bicocca 4

LV- workshop during CMS electronics week General discussion ......& answers What hardware interlocks do you use on the LV and HV Systems?..................... ...........Built –in caen system According to our request a new firmware for the A4603 has been implemented, so now the HV can ramp down to V0 using a signal generated by the LHC and sent by the BRM directly to the Pixel CAEN system ( V sel input ) The LV is unaffected. Who’s in charge of keeping the LV & HV systems working?................... ........Gino Bolla, Mauro Dinardo, Pasquale D’Angelo, Bill Gabella, Lalith Pereira And the interface with DCS? (CAEN system, and Branch drivers).......... .......Gino Bolla, Mauro Dinardo, Pasquale D’Angelo, Bill Gabella, Lalith Pereira. 8/06/2010 Pasquale D’Angelo – INFN Milano Bicocca 5

Quickly test the devices malfunctioned. PIXELS SUPPORT ACTIVITIES PERFORMED AT TIF In addition to the PILOT DETECTOR, an improved TEST FACILITY can perform varius technical functions. Here the most important: 1) Control all the spare devices ,and make sure they are ready for replacement. 2) Quickly test the devices malfunctioned. 3) Long term test on devices with suspected faults. 4) Test the functionality of the new Firmwares. 5) Run all the functional test on prototypes devices for next CMS-UPGRADE. 6) Activete a very simple set-up (with Panel + Adapter Board + Flex Cable + Port Card + Aoh) on which we can easily operate, to try to understand and address problems, in attempt to avoid future occurences. 7) Help to maintain under control all the PIXELS devices used at P5. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 6

IMPROVEMENTS ON THE.......... Power Supplys Test Facility Setup Same configuration used at P5 A3486 MAO A3486 (mao) Dummy loads MSC-long cables (43m) Spare crates & modules Modules under test 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 7

BUS CONNECTIONS . . . . . . The A1676 Branch Controller handles a chain wich includes both: EASY crate and A3486 (MAO) A3486 (MAO) (INPUT connector) A3486 (MAO) (INPUT connector) 2x2KW/1x4KW 48Vdc Power source A1676 Branch Controller (OUTPUT connector) Easy crate panel (INPUT connector) Mainframe Easy crate overview Branch Controller overview The crate, which is suitable to host P.S. Modules A4602 & A4603 is handled by one of six branches of the A1676 Branch Controller. The Branch Controller must be linked to the EASY crate usually placed in the “ostile area” The A1676A is the interface between the Mainframe and the remote boards in the Easy crate. The channels of the Easy boards will operate as channels of the A1676A. Up to six Easy crates can be controlled by one A1676A. The crate panel is provided with I/O flat connectors of the Easy Bus Remote control and the 48V Status Input connector, wich allow the PS boards microcontrollers to detect failures in supply voltages and consequently to enable PS channels ramping down. Easy crate 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 8

CAEN devices – Firmwares overview Firmware Version Issued on Currently used at P5 1.04 Nov.2009 1.04 1.03 Jul. 2009 1.02 May 2008 1.01 Dec. 2007 Power Supply A4603 Power Supply A4602 1.03 May 2008 1.03 1.02 Jan. 2008 2.04 May 2008 2.04 2.03 Dec. 2007 1.10 Apr. 2007 48 Vdc Converter (MAO)-A3486 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 9

CAEN devices – Firmwares overview Firmware Version Issued on Currently used at P5 3.01.05 Nov. 2009 3.01.05 3.01.02 Mar. 2008 3.01.01 Feb. 2008 3.01.00 Jan. 2008 3.00.00 Dec. 2008 2.01.02 Sep. 2006 2.01.01 Jul. 2006 2.01.00 Jul. 2005 2.00.02 Feb. 2004 Mainframe SY1527 3.01 Dec. 2009 3.02 2.12 Nov. 2008 2.11 Jun. 2008 2.10 May. 2008 2.09 Sep. 2006 2.04 Jul. 2005 Branch Controller A1676A 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 10

New features of the FIRMWARES used by PIXEL Communities Branch Controller A1676A In the new Firmware (rel. 3.01) the Vsel bug has now been corrected Bug fixed : Internal memory corruption caused by the use of the Vsel parameters. Power Supply A4603 According to our request with the new Firmware (rel. 1.04) the H.V. can ramp down to V0. The L.V. unaffected As a result of these new features will be possible use a signal generated by the LHC and sent by the BRM directly to the pixel caen system ( Vsel input ) The A4603s will then ramp down from V1 to V0. The A4603 L.V. Is unaffected. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 11

Simple and Easy TEST STAND act to understand and address problems. We can use the same TEST FACILITY used for the PILOT DETECTOR Test Stand details Port card + CCU + AOH Panel + Adapter Board + Flet cable 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 12

CMS – Pixels DEVICES To control all the DEVICES used at P5 has been created a link on TWIKI Where you can find an UPDATE MAP of the Power System Parts installed. You can find also a MAP of the DEVICES Out of the System.…( Spare Parts.) twiki.cern.ch/twiki/bin/view/CMS/PixelCaenSpareComponents Our idea is to improve this very useful tool, extending it to other devices …( FED…FEC…etc. ) and adding a history of any inconvenient occurred on that device. This would help us to TRACE the history of the Channel.…Layer….Sector. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 14

SUSPECTED MALFUNCTIONS…………….. _ Sometimes happens that a power unit ( A4602, A4603 ) goes bad, so suspecting that the module has problems, we replace it. _ The swapping process fixes the problems, but the replaced unit ….tested at TIF…. is OK _ So the problem is solved but still…… we don’t know why. _ We had several technical interview with CAEN Engineers to understand in detail how the modules works. HERE ARE THE ANSWER. The Firmware for A 4602 and A4603 are stored in a flash Eeprom inside a Micro Controllers which handled the module. There is NO “Firmware Load” at Power ON. Therefore a corruption of the Firmware can NOT be recovered by a Power Cycle. Each time a module is removed and re-inserted into the crate,( which is equivalent to power cycle the crate ) there is an integrity check of the Firmware. If the integrity check is not passed, then the module can no longer be accessed, and the Firmware must be reloaded into the Eeprom. The RESET button on the front panel acts directly on the microcontroller, and perform a reset of all channel for that module. Through Telnet can be performed a so called HW Reset, which will Reset all the modules in one crate. The Recovery-command through Telnet, resets only the communication. The channels remain on. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 13

Summary Here are been mentioned the most important All the activities currently being held at TIF play a support function mainly for the PIXEL COMMUNITY Here are been mentioned the most important Others activities will arise in the light of the coming CMS - UPGRADE 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 15

FINAL REMARKS and CONCLUSION For what concern pixels ( Barrel & Forward ) we can said : - The Power Supply failure rates is extremely low. Are already several months that we don’t observe failure on our devices. My personal opinion: This very high efficiency is mainly due to the big effort of everybody done during the commisioning, and the preliminary test made in the past. And also thanks to the “CONSTANT & PERMANENT............... Pixels support activities performed at TIF. 8/06/2010 Pasquale D’Angelo – INFN Milano - Bicocca 16