LAV thresholds requirements

LAV DCS requirements

LAV thresholds requirementsPaolo ValenteLAV answers for Valeris questions (old)List of hardware to control (HV, LV, crates, temperatures, pressure, etc) , including number and nature of channels, refresh rate, etc.Answer: 2496 crystals:2496 HV channels (in 32 or 48 boards, see next slides) + HV crates status, fan, temperature24962 thresholds (in 32 custom VME boards) + Wiener TEL62 crate status, fan, temperatureForeseen control interfaces, in particular for non standard equipment The custom Time-over-Threshold discriminator VME boards will have a CPU and a CANOpen interface:firmware will be developed by LAV teamPart of the software probably also will be developed by LAV team (a custom OPCServer?...) We will have more details as soon as the front-end electronics project for LAV will be completed (and we will have the final boards with the CPU, remote control of thresholds, etc.)Special and non-standard requirement for user interface, alarms, actions, etc.Nothing really specialy for the LAV stations, they could be considered as twelve independent calorimetersThe only special care to be paid is that even ONE dead or not properly working channel can be a problem for the experimentHow your requirement willevolvebeyond the 2011 run up to the final set-upFor a synchronization run in 2011 we will have already half of the stations in final configuration (apart from front-end electronics)The HV system can be practically final by thenThe LV system (threshold and front-end boards control) will be needed for just a few pre-prodcution boardsWhat will be your participation in the DCS preparationAs much as we can we are man-power limited

LAV answers for Valeris questions (new)Do you only set the threshold? Answer: No, we want to set and read back the actual threshold value24962 thresholds to be set and actual values to be readoutActual threshold should match the required value (in a given band, see next) taking into account known offset (stored in the DB) for each channel A new set of thresholds implies:Starting a new run New entries in the configurations and conditions DBs how often?New thresholds would be probably needed in order to tune the efficiency of each single block inside the LAVs, after having estimated the response with data. This is something we expect change quite slowly (certainly not once per spill), since sufficient statistics should be collected for measuring efficiency (with muons from the beam halo or photon/electrons from a selected sample),Presumably this will be performed (at least during stable data-taking) by an automatic calibration task: I estimate very roughly a new set of thresholds every few hours, to start with, that would become a new set every day (or few days), in stable conditions. LAV answers for Valeris questions (new)Do you need reading them?Answer: Yes How often? Dead band?Can be a slow readout, of order of minutes: a drift due mainly to temperature effects is expected. Dead band should be a fraction of 1 mV (if typical thresholds range between few to 10-15 mV, 1-2% should be fine)In addition, an asynchronous readout command could be useful, in order to read e.g. at run initialization or every given number of spillsDo you need alarms? Yes, if (readout value-required value) >> readout error. Probably, something in the range of 0.5 mVDo you need trending, archiving?Yes, at least at the level of the online archiveAverage values per run would be probably enough for offline conditions DBLAV answers for Valeris questions (new)CANbus technologyRationales behind the choiceA working solution already exists, even though applied to a different piece of hardware, LHCb GEM HVExpertise available moreover the same electronics design team is available (Gianni Corradi, LNF)Your vision of sharing of the jobProgramming of firmware inside the board will be done by the Frascati teamA test setup with PVSS could be arranged in Italy, either in Rome or Frascaticertainly with the driving force and intelligence from the central DCS teamWe are looking for young people for actual programming, even though I expect a great part of the job will be the massive configuration of the final system, probably a little less work will be required for a test setupScheduleAs soon as first production boards will be available (we are waiting them for end of May 2011)but also subject to finding some help in Italy

More on LAV threshold systemSummary of LAV systemStationN. Of layersCrystals/layerCrystals/station153216025321603532160453216055321606548240754824085482409460240104602401146024012464256Total2496

Mapping

CAN channelCrate (CAN node)channelVME Board (CAN node)StationLayerCrystal

1 VME Board = 1 Layer for first stations Configuration DBCrystalThr_ref_mvThr_off_mvCount_to_mvME05722.30.380.2CrystalCANLineCANNodeBoardChanEnabledImaxME057201201500