ABRA was going to be the POCUS or CHANGEO for the Nanometrics
Centaur units. It got far enough to figure out which units
were connected, ask for the status of units, restart and
shutdown enumerated units.
Unfortunately the OS running on the Centaurs just was not
designed to be bothered with talking to a program like
this. There was no way for good two-way communications. The
working functions were handled by ssh'ing (logging into) the
Linux backend, issuing commands, like on the command line, to
figure out what was going on and do things like reboot the
units. Most of the time was spent issuing a command, and then
asking/delaying until the results became available. Most of
the few possible things that made changes to a unit's
configuration required rebooting. Centaur reboots take 4.5
minutes. It all made things very slow and cumbersome.
Many emails were sent back and forth to Nanometrics to figure
out how to do the simple things the program ended up doing,
but basic things, like setting the IP address of each unit,
was never did work.
Before starting ABRA I managed to build an Ethernet switch
that could have its ports turned off and on programmatically.
When the units come back from the field they all may have
different unknown Ethernet IP addresses set in the field, or
the same addresses that are set during bench testing, but they
all respond to a known single address for three channel units,
and another address for six channel units. The first order of
testing business is to set them all to a different IP address
so only one can be connected at a time while this is
done. Once a unit's address is set it must be disconnected and
the next one connected. This continues until all of the
addresses are set. What a pain. This contraption was built to
perform the connect-disconnect shuffle without actually having
to connect and disconnect Ethernet cables, which is the way it
is currently done.
The device is made up of a regular Netgear GS316 16-port
switch, a Numato Lab 8 Channel USB Relay Module, and eight
Ethernet pigtails. Each relay makes or breaks the RJ45 pin 1
connection of one pigtail. Opening that connection is enough
to make a Centaur think there is no Ethernet connection
causing the unit to stop listening. Controlling the module is
done through ASCII commands sent by ABRA. Eight ports of the
switch are controlled, and the other eight are just normally
active. The total cost was about $350.
Both the switch and the relay control board run on 12VDC which
is supplied by the silver-finned power supply. The only
alteration to the Netgear switch was drilling a few screw
holes in the cover to anchor the parts on top.
CADABRA was going to be the same kind of program for the Nanometrics Pegasus units, but they have the same communication deficiencies.
2023-03-16