July 10, 2015
David Lawrence
davidl@jlab.org

Updated Jul 22,2015 DL
Updated Jul 24,2015 DL


This system contains software for running CODA on the single board computer 
(aka ROC=readout controller) for the purposes of reading out a fADC-125
module. The operating system is Linux CentOS5 and is contained on a
CompactFlash card on the ROC itself. No external network is therefore
needed to boot the ROC.

There are 2 other disks required for running the system:

1. USB thumb drive - plugged into any USB port on ROC
2. USB hard drive  - plugged into any USB port on ROC

The first drive must have a volume name "CPP_thumb" and the second
"CPP_500GB". Otherwise, they will not be mounted properly. The thumb drive
contains the CODA software while the USB hard drive is used to hold
the data. It is formatted using vFAT so this drive can then be moved over
to any other computer (Linux, Windows, Mac OS X) for data analysis. 

To unmount the data drive:

$ sudo umount /mnt/CPP_500GB


To mount the data drive:

$ sudo mount /mnt/CPP_500GB

Before you start
====================================

Before starting up the DAQ system make sure both drives are mounted.
The USB thumb drive will usually not mount automatically when the
crate is powered on (not sure why). If the drive is not glowing
orange then un plug it and plug it back in. You may then need to
mount it by hand using "sudo mount /mnt/CPP_thumb". If in doubt about
the status, just enter "df" to see a list of all mounted drives.

In order for CODA to work it needs to be connected to a network.
(This is due to the heavy use of multicasting.) The minimal system
needed is to have an ethernet hub attached to the top LAN port on
the ROC. Make sure the hub has its power cord plugged in and that
you see a green link light on it before starting CODA.


Running CODA
====================================

To start CODA just open a terminal window and enter the following:

$ start_daq

Multiple windows will open including the Run Control Gui which
is used to control the DAQ and take data. Occasionally the rcgui
window won't open. This is due to the "platform" program not being
ready when rcgui tries to connect to it. If this happens then
just kill the DAQ system and restart it.



To kill all CODA programs, enter the following:

$ kill_daq

This should kill all of the CODA processes. Use this if the system does
not behave properly and you need to restart from scratch. 


Analyzing the data
====================================

Data is stored in the Disk2/data directory. To convert the data
from EVIO format to ROOT format, issue a command like the following
while in the data directory:

> hd_root -o fmwpc_proto_000078_000.root -PPLUGINS=DAQTree fmwpc_proto_000078_000.evio

where "78" is replaced with the run number of interest.

Also in the data directory are two files:

scan_waveform.C
scan_waveform.h


These were initially created using the TTree::MakeSelector() method. For
example:

> root fmwpc_proto_000078_000.root
root [0] Df125WindowRawData->MakeSelector("mytest")

creates 2 files: mytest.C and mytest.h. The file scan_waveform.C was
modified to display individual waveforms as histograms. It is intended
to serve as an example for how one may access the data in the ROOT file.


CONFIGURING the fADC-125
====================================

Configuration settings on the fADC-125 will need to be adjusted
in order to capture the signals within the time window that is
read out. The CONFIG directory contains the relevant files and
the README file there gives some details on each.