Here we describe the format of pre-defined files that are used in SCT DAQ. These files are in XML (Extensive Markup Language) and an excellent tutorial is available at: http://www.w3schools.com/xml/
The DAQ of the SCT at Oxford is controlled the by user 'daquser' on the machine, ppatlas1.ox.ac.uk. The home directory for the purpose of this document is the home directory of the 'daquser' on this machine.
Modules are mounted on the barrel in rows of 12. Each row is divided into two groups of 6 modules, one on the Z- end of the barrel and the other on the Z+. Each half-row is serviced by a seperate LMT (Low Mass Tape) ie. the tape which carries the power to the modules. As a result the half-row are often reffered to as LMT Z- and LMT Z+.
All the configuration files for a particular barrel are stored in a single directory. For example, the configuration files of Barrel3 can be found in ~/BarrelConfig/Barrel3.
The file ~/BarrelConfig/Barrel3/Barrel3.xml defines the half-rows the DAQuser wants to read out. Modules are read out half a row at a time. This is the Minimum Unit of Readout, or MUR.
Below is a list of elements and attributes, in the Barrel files.
rod : ReadOut Driver in the crate, starts from 0. references MUR files. slot : Slot in the ROD crate tim : timing module
An MUR file contains information about the 6 modules that are on a half-row. The names of the MUR files follow the convention: lmtXX/MURbsXX?.xml.
b : barrel number: 3, 4, 5 or 6 s : side of the barrel, 0 for Z- or 1 for Z+ XX : lmt row number: 01, 02,...
In the MUR files the positions of the modules are numbered from 1 to 6 from the center of the barrel and going outwards. The same convention is used in the B3_mapping.xls file which shows the TX (transmit signal) redundancy flow. In the module mapping file, B3ModuleMap.txt, however, the module positions are numbered from 1 to 12. The correspondence between these two conventions is pictured below:
Z+ (s=1) | Z- (s=0) +6 +5 +4 +3 +2 +1 | -1 -2 -3 -4 -5 -6 12 11 10 9 8 7 | 6 5 4 3 2 1 U L U L U L | U L U L U L
In this table, L means that a module is a lower module and U denotes an upper module. The modules overlap (or are cascaded up and down) in phi to provide full coverage. Due to this overlap, replacing a lower module requires two upper modules to be taken off as well. The lower modules are put on the barrel first and tested. Only after they are confirmed to work properly, the upper modules are mounted.
Each barrel has different number of LMT rows on it. Barrel 3 has 32 rows and each next barrel gets an extra 8 rows. So barrel 4 has 40 rows and barrel 5 has 48 and barrel 6 has 56 rows.
Each LMT directory contains Below is a list of elements and attributes, in these MUR files.
Element Attribute Contains
---------------------------------------------
MUR order order of fibre ribbon at BOC. start counting
at 0 from bottom of BOC.
id bsXX as before
module id Position 1-6. references corresponding module files.
group Trigger group from 0..7. Trigger is defined at
control level.
Trigger received (0 or 1) is group/4, ROD Slave
DSP used (0...3) is group%4.
rmodule id Position 1-6. an example:
< rmodule id="2" > tag means, that the dogleg
that is at position 2 can send a signal to the
module that is defined in this field.
channel id same as module id
output TX (Transmit) signal
current the bias current for the VCSEL (Vertical Cavity
Side Emission Laser)
delay adjusts phase of TX to accommodate different
fibre lengths + TOF from IP
markSpace adjusts the markSpace(duty cycle) of BPM chip
stream{0,1} RX (Receive) fibre used to transmit data from
the top and the bottom faces of the module
threshold fibreoptical threshold (0..255) used to
discriminate received optical signal.
(corresponds to the pin current in microAmps --?)
delay adjust phase of RX data relative to system
clock in nanosec. (0..24)
More information about delays and timing the modules in for physics running and cosmics running are now being compiled under TimingIn.
The module configuration files mentioned above are under lmtXX/module/20220ss0200nnn.xml. The module names are always 14 characters long where ss = production site with 04=US, 17=Japan, 33=UK, 38=Scandinavia and nnn=serial number.
Under the lmtXX directory, you will sometimes find a directory that is called old_module. This directory is there for historical reasons and contains module configuration files which have the <c_factor> tag set to 1 always. <c_factor> is the calibration factor, which is now set in the actual configuration files to a number other than 1 from tests of the test-structures on the wafers.
A module configuration file is documented under ModuleConfig.