aircoa2 stopped transmitting data this afternoon at 13:08 MDT.

Here's the entry in /var/log/local/isff.log:
Sep  1 13:08:54 10.0.0.14 AirCOASampler[110]: IOException: SensorPortHandler: select: Cannot allocate memory
Sure enough, it's a memory problem.  
After a struggle (it wouldn't ping, and then later would ping intermittently,
and finally would allow me to ssh in), I was able to log in and kill
the aircoa process.    The new aircoa code, with the new leaner XML
parser is now installed on aircoa2.  Hopefully it won't have the
memory problem.

After starting aircoa, ps reports it to be taking 16744 Kbytes.
We'll watch it...

  157 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  158 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  159 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  160 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  161 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  162 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  163 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  164 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a
  165 root      16744 S   aircoa -r cme.txt cme -x li820.xml -t /dev/ttyS2 -s a