Model 106-L Ozone Monitor Manual Rev. E
7
accurate measurement, the instrument must have been turned on long enough
for the internal temperature to stabilize. The observed offset, which can
amount to
a few ppb, can be corrected for by changing the offset calibration
parameter (Z) from the front panel, as described below.
Collecting Data over the Serial Port in Real Time
To transmit data to a computer over the serial port in real time, connect the
Ozone Monitor to the serial port of the computer using the 9-pin cable provided.
Note that this is a “straight-through” female-female serial cable. A “cross-over”
cable will not work. Start your data acquisition software, preferably using the
2B Technologies Display and Graphing Software (free download from
http://twobtech.com/software.htm
). Other terminal emulation software such as
HyperTerminal (a program provided with Windows) or
Tera Term Pro
may be
used as well.
The ozone mixing ratio, internal cell temperature, cell pressure, time and date
are sent as comma-delimited ASCII text to the serial and USB ports (2400,
4800 or 19200 baud as selected in menu; 8 bits; no parity; 1 stop bit) every ten
seconds, 1 minute, 5 minutes, or 1 hour, depending on the averaging time
selected from the microprocessor menu. Time is provided in 24-hour (military)
format, and the date is given in European style (day/month/year).
A typical data line would read:
3.2,309.4,759.3,840,1.212,15/10/2010,18:31:27
where:
Ozone = 3.2 ppb
Cell temperature = 309.4 K
Cell pressure = 759.3 torr (1 atm = 760 torr)
Flow rate = 840 cc/min (volumetric)
Photodiode Voltage = 1.212 volts
Date = October 15, 2010
Time = 6:31:27 pm
If outputting logged data, the output serial data line will be preceded by the log
number; e.g.,
2893,3.2,309.4,759.3,840,1.212,15/10/2010,18:31:27
where 2893 is the log number.
