Model 202 Ozone Monitor Manual Rev. J-4
8
such as HyperTerminal (a program provided with earlier versions of Windows) or
Tera
Term
may be used as well.
The ozone mixing ratio (ppbv), internal cell temperature (K or °C), cell pressure (torr or
mbar), volumetric flow rate (cc/min), values of three external analog inputs in volts (if
activated from the menu), date, and time are sent as comma-delimited ASCII text to
the serial port (2400, 4800 or 19,200 baud; 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).
With analog inputs activated from the menu, a typical data line might read:
67.4,35.3,980.6,850,1.3876,2.3143,0.1875,15/10/18,18:31:27
where:
Ozone = 67.4 ppbv
Cell temperature = 35.3°C (may be expressed in K if chosen from menu)
Cell pressure = 980.6 mbar (may be expressed in torr if chosen from menu)
Volumetric flow rate = 850 cc/min
Analog input A = 1.3876 volts
Analog input B = 2.3143 volts
Analog input C = 0.1875 volts
Date = October 15, 2018
Time = 6:31:27 pm
The three external inputs are omitted from the data line if they are turned off using the
menu, as described in Section 3.17 below. The analog inputs allow measurements
made by other instruments to be transmitted to a computer simultaneously with those
of ozone and the time and date stamp; these inputs may also be logged in the
instrument’s internal memory, as described below. Examples of external
measurements that are commonly made along with ozone are external temperature,
pressure, and relative humidity, but the outputs of any instrument may be input to the
Ozone Monitor. The analog inputs may range from 0 to +2.5000 volts and are
measured with an accuracy of approximately
0.0001 volt.
Caution: An input voltage
greater than +5.0 volts or less than
–0.3 volts may permanently damage the instrument
.
If the Ozone Monitor has been set to the
“log data” mode, the output serial data line
will be preceded by the log number; e.g.,
2893,67.4,35.3,980.6,850,1.3876,2.3143,0.1875,15/10/18,18:31:27
where 2893 is the log number.
In addition to data lines, messages are written to the serial port when logging is begun
or ended, when transmission of data from the logger is begun and ended, when data
collection is interrupted (e.g., due to a power failure), and when the averaging time is
changed.
