DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 1 Interface between Control & Monitoring and DDAQ o Introduction o Some background on DATE o Control Interface o Data Interface Proposals 1) Asynchronous Interface 2) Synchronous Interface o Summary Jean-Sebastien Graulich, Geneva

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 2 Introduction  Basics: Control and Monitoring (MCM) Runs continuously, asynchronously and at low update rate (a few Hertz) Uses relatively small bandwidth Basics: Broadly distributed: It reads data from many different sources located in many different places and using many different hardware  Basics: Detector DAQ (DDAQ) Runs on demand, synchronized with the beam Uses very large bandwidth: ~100 MB/s Slightly distributed: It reads data from VMEBus (6 crates) with a unique Interface

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 3 Introduction  Basics: Interface 1) MCM should know and archive the status of DDAQ 2) DDAQ should not run when MICE is not ready In particular the run should be stopped when something goes wrong in one subsystem 3) DDAQ should incorporate some data under the control of MCM which have a physical meaning: e.g. Hall Temperature, Pressure and Temperature in the Absorber, Current in the magnets, etc At some point we will need a list… Control Interface Data Interface

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 4 Some Background on DATE  DATE is the CERN-ALICE DAQ software framework  It provides one essential element that we don’t have time to develop by ourselves: the eventBuilder (which put together the event fragments collected by the different PC connected to different VME crates)  Me and Vassil are currently being trained to DATE within the ALICE group  DATE uses the DIM (Distributed Information Manager) Software Package which allows sharing information over many hosts.

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 5 Some Background on DATE: DIM  DIM Principle: Servers make some data available as a service Clients may subscribe to the service and receive the data when it is updated Clients can also send Commands to the server The Name Server allows the client subscribing to a service without knowing a priori which is the server providing it. DIM is lightweight and extremely portable

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 6 Control Interface  It is easy to write a DIM Client which can monitor the Run Status. If it is also an EPICS Server, it can tell the MCM what is the run status  It is easy to write a DIM Client which can stop the run properly. If it is also an EPICS Client, it can stop the run on the basis of the MCM status  -> No problem expected for Control Interface (assuming EPICS expertise is available)

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 7 Data Interface Proposal 1  Asynchronous Interface DATE has a built-in feature that allows executing shell scripts at the beginning and at the end of a RUN and to attach some user files to the data stream at the end of the run An EPICS Client can be started at beginning of the RUN, collect the interesting data asynchronously, and write them on a local file with time tag. At the end of RUN, the file is send to the data stream, so it is stored together with the detector data. Advantage: That is precisely what we are implementing for ALICE, in compensation for the training time they spend on us DDAQ is not affected in case of slow response time of MCM Inconvenient MCM status is not known on a Spill per Spill basis. Analysis more complicate

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 8 Data Interface Proposal 2  Synchronous Interface The EPICS Client can be implemented in the readout loop of the PC connected to the trigger crate. The MCM data is readout at the end of each Spill Advantage: The MCM status is know on Spill per Spill basis Inconvenient: DDAQ is affected in case of slow response time of MCM Not tested  I suggest to start with asynchronous interface and upgrade to Synchronous Interface later

DAQ WS03 Sept 2006Jean-Sébastien GraulichSlide 9 Summary  Interfacing DDAQ with MCM is reduced to interfacing DIM and EPICS  No problem expected for Control Interface  We have to decide between Asynchronous or Synchronous Data Interface  We should first define the precise list of Data