From the webplots, it is obvious that dew frequently forms at night on the EC150s, which obscures the optics and causes bad data. The same thing happened in SAVANT. Since CHEESEHEAD is a CO2-centric program, this behavior is not desirable. The EC150 has heaters that can be turned on or off or run automatically to maintain a temperature just above (2 deg.) ambient. This is set by the menu S/M, where -2 is automatic, -1 is off, and any positive number (0 to 4.5) is a heater voltage. Factory default is -1, but Ed at Campbell recommends -2. We need to check each of these to ensure that the heaters are set to -2. If they already are, we should consider turning the heaters full on (4V?) for a period (10min?) sometime after sunset and then turning the heaters off. (Having the heaters on can contaminate the data by changing the density of the air, so we will reject data when they are on.)
Unfortunately, setting S/M is difficult to do with the datastream running over the serial port, so it is easier to check/change while plugged directly into the EC100 USB port (requiring that the mast is down). I recommend doing this along with our next visits to clean sensors.