Data Logging
The GSM220 logs CO2, air temperature, and relative humidity readings
(along with date and time). The memory capacity is 15999 points (5,333
CO2, temperature, and humidity records). The sample rate is adjustable
(in the setup mode) from 1 second to 4 hours, 59 minutes, 59 seconds.
After setting the sampling rate, long press the LOG button to start
logging. The green LED blinks while logging and the main display
digits alternate between real time CO2 readings and the
abbreviation ‘rEC’ (record). The lower displays show the real time
temperature, humidity, date, and time.
To stop logging, long press the ESC button. The LED stops blinking, and
the main display will alternate between real time CO2 readings and the
word ‘End’. Long press the ESC button again to return to the normal
operating mode. See the PC Datalogger Software section, next, for
details on downloading logged readings to a PC.
Note that the MIN/MAX memory is still operational during data logging
and is cleared each time a logging session is started.
PC Datalogger Software
The supplied Windows-based PC software and USB cable allow you
to set-up the datalogger, download logged data, and view the logged
data graphically or in text format on a PC. The software and USB
driver is also available from the Extech website.
Connect the GSM220 to a PC using the supplied USB cable. The USB
port is located on the back of the GSM220. Install the software, open it,
and refer to the program HELP utility for complete operational
information. Contact Extech support if you have questions or problems.
Alarm Function
The GSM220 features an audible (beeper) and visual (flashing fan icon)
alarm that warn when the CO2 concentration exceeds the programmed
threshold. There are two alarm thresholds, the ‘POOR’ air quality
threshold (that triggers the alarm), and the ‘NORMAL’ air quality
