Information on Operating the COMPASS DAQ



DATE Run Control | DATE Information Logging | Configuring the DAQ | Online Filter | Monitoring | Auxiliary Software | Central Data Recording | FAQ to Lars


DATE Run Control

COMPASS uses the data acquisition software package DATE written by the ALICE data acquisition team. You may obtain the latest documentation as
PS or PDF if you're in the COMPASS domain.
You have to know the following steps to start the data taking:
  1. Log in as daq on the COMPASS run control machine in the control room in 888.
  2. To start the run control type   dateControl
  3. Click the lock icon to acquire control over the runControl background process.
  4. Connect to the active machines by pressing the right arrow.
  5. Prepare the run parameters by pressing the next right arrow.
  6. Start a run by pressing the START RUN button.
  7. Stop a run by pressing the Stop button.
  8. Disconnect from the participating machines by pressing the left buttons at the end of a data taking period.

In case of hanging DAQ (more than 30 seconds without response) abort with the command:

cleanDate
It will close the run control and all DATE processes. Start again with dateControl afterwards.

Some more information about the system can be found in the DAQ tutorial 2006 (PDF).

Information Logging

You may browse the DATE logfiles online through a JAVA servlet via WWW. On the COMPASS run control machine you can also use infoBrowser. To see run statistics of recorded files use the DATE statsBrowser.

Information on runs is logged via the electronic logbook.

You may monitor the status of online machines via netsaint, a network monitoring tool.

Configuring the DAQ

Online Filter

COMPASS uses an online filter running in pipeline with the eventbuilder processes on the eventbuilder computers to reject bad events and reduce the rate to be recorded to disk. Its state can be set through the run control: Check the documentation on Cinderella to learn more about the online filter.

Monitoring Software

DATE offers the possibility to sample data online using a monitoring library. This library exists in two versions, a C library and a C++ library based on ROOT. Sample codes with decoding facilities of COMPASS F1-TDC data (from CATCH CMC or Hotlink) exist: To simply look at data printed in ASCII and HEX you may use DATE's eventDump program. The source of data for eventDump and any other monitoring program using DATE libraries can be specified in three different ways: To decode your data important information can be found in COMPASS Note 2002-8. To uniquely mark an equipment within COMPASS source IDs have been assigned to each detector. Use this to find the detector you are interested in.

Auxiliary Software

The TCS server controlling the TCS system sends a TCP/IP multicast to announce some spill related information during data taking. A client program to listen to these multicasts is provided. The output of this program is the data line transmitted by the multicasts, a string of 60 bytes length. For each sub DAQ are given. The last field is three byte with the spill status, 1800 for begin of spill and 800 for end of spill. Each byte corresponds to a hex number. All fields are separated by single blanks. An output sequence could look like this:
prompt> spillclient
1f 004 1f 001 1f 0c9 00 000 00 000 00 000 00 000 00 000 1800
1f 004 1f 001 1f 0c9 00 000 00 000 00 000 00 000 00 000 800
1f 005 1f 002 1f 0ca 00 000 00 000 00 000 00 000 00 000 1800
1f 005 1f 002 1f 0ca 00 000 00 000 00 000 00 000 00 000 800
00 000 1f 003 1f 0cb 00 000 00 000 00 000 00 000 00 000 1800
00 000 1f 003 1f 0cb 00 000 00 000 00 000 00 000 00 000 800
There is as well a simple program waiting for offspill included.

Central Data Recording

Central Data Recording is provided by CERN group IT/PDP. The software interfacing the COMPASS DAQ to the central infrastructure was written by Massimo Lamanna. Look on the Central Data Recording page to find out how to access the data you are interested in. See also the pages on the COMPASS Computing Farm CCF.

Frequently asked questions to Lars

Frequently asked questions on the operation of the COMPASS DAQ will be posted here (with answers, of course). If you have a question or are missing a piece of information which should appear here write to Lars Schmitt.

Which phone number does barrack XY in 888 have?
See the list of all phone numbers in 888.

Last update: 11/11/2004 by Lars.Schmitt@cern.ch.