Introduction
SrPar2Ew allows the Symmetric Research PARxCH family of low cost
24 bit data acquisition systems to send data to an Earthworm system
running either Windows (Win2K, WinXP) or Linux. PARxCH models with 1,
4, and 8 channels are all supported. It can also support 16 channels
if run with 2 PAR8CH on the same PC which share one PARGPS. Very
accurate timestamping of the acquired data results when the optional
PARGPS timing unit is used with the PARxCH A/D. Timestamping using
the PC system time set by NTP is also available.
SrPar2Ew reads configuration information like sampling rate and
PARxCH model from an Earthworm style .d configuration file and then
opens drivers and initializes hardware for the PARxCH and optional
PARGPS. Then it starts the A/D and goes into an infinite loop
acquiring data, converting it to Earthworm tracebuf (or tracebuf2)
format and writing it out to the specified Earthworm ring. On each
pass through the loop, it also sends a heartbeat message to the
Earthworm ring.
In order to run SrPar2Ew, you need a working Earthworm system, a
PARxCH A/D board, and the PARxCH device driver and library software
that comes with the board and is also available free from the
Symmetric Research website
www.symres.com.
For accurate timing information, a PARGPS timing unit and its software
is also required.
Setup
Follow any instructions given in the official documentation to get
Earthworm up and running.
The first step in adding PARxCH data is to install the PARxCH with GPS
software. This can be done by unpacking the pxgpsw2k.zip or
pxgpslnx.tar file and running the included install script to copy the
SR software to the \sr\parxch and \sr\pargps directories. Linux users
should substitute /usr/local/sr/parxch for references to the
\sr\parxch directory.
You will also need to install the PARxCH and PARGPS device drivers
using the indriver utilities from their respective driver
subdirectories. See the readme files in the \sr\parxch\driver and
\sr\pargps\driver directories for more information.
Then hook up the A/D hardware. Make sure it is working correctly by
running the diagnostic program in the \sr\parxch\diags directory. The
acquisition programs in the \sr\parxch\scope and \sr\parxch\simple
directories can also help in checking out a new system.
To add the PARGPS (optional but recommended), first install the PARGPS
device driver using the indriver utility provided in the PARGPS
software. See the readme file in the \sr\pargps\driver directory for
more information. Then hook up the PARGPS hardware. Make sure it is
working correctly by running the diagnostic program in the
\sr\pargps\diags directory.
Once Earthworm and the PARxCH/PARGPS are working on their own, it's time
to get them working together. Edit the srpar2ew.d configuration
file settings so they are appropriate for your system.
At this time, you will probably also want to edit some additional
Earthworm module configuration files to handle the PARxCH data that
will be coming. This might include adding tanks for the PARxCH data
in wave_serverV.d if the data is to be saved on the same computer or
setting the PARxCH channels in export_scn.d if the data is to be
exported to another computer.
In the beginning, it is probably best to use two separate command
prompt windows. In the first, run startstop to start Earthworm. In
the second, type "srpar2ew srpar2ew.d" without the quotes
to start the PARxCH acquiring and sending data.
You can check the log files and run diagnostic programs like sniffring
to help diagnose any problems. If something isn't going right, it is
easy to stop SrPar2Ew, modify its configuration file, and
restart it without having to stop the rest of Earthworm. Once you've
got your parameters set right, then go ahead and have startstop
control SrPar2Ew too.
Compiling
SrPar2Ew is written in C and is compiled and linked using the
standard Earthworm makefiles such as makefile.nt. In order to
successfully compile, access to the PARxCH and PARGPS system software
is required. This software, including source, is included with every
PARxCH and PARGPS purchase. It is also available for free download from
the Symmetric Research website
www.symres.com.
All Symmetric Research software, including the PARxCH system software
and SrPar2Ew, has been designed so a single set of source code
can service different operating systems. This is accomplished
primarily through the use of conditional compilation which selects OS
specific code at compile time based on which SROS_xxx setting is defined.
Valid options include SROS_WIN2K (for both Windows 2000 and XP) and
SROS_LINUX. Solaris is not available.
Although using a PARGPS timing unit is optional, it is recommended.
Even if you are not using the PARGPS, you should always install the
PARGPS software and define GPS_AVAILABLE when compiling the PARxCH and
SrPar2Ew software, so the timing portions of the code are
included.
More Info
General questions about Earthworm are probably best answered by
the official Earthworm User's discussion group. But, if you have
specific questions about SrPar2Ew and its configuration
parameters, please let us know at
info@symres.com.