Model 306 Ozone Calibration Source Manual Rev. G-1
14
5.
USING THE SERIAL INTERFACE
5.1
Collecting Diagnostic Data over the Serial Port in Real Time via the LCD
Collecting serial data for a few minutes can be extremely useful in diagnosing a
problem with the Ozone Calibration Source
™. To transmit diagnostic data to a
computer over the serial port in real time, connect the Ozone Calibration Source
™ to
the serial port of the computer using the 9-pin cable provided. If your computer does
not have a serial port, you can use a serial-to-USB adapter, available at most
computer stores or at our online store (see Section 11). Activate your data acquisition
software; e.g., HyperTerminal (a program provided with earlier versions of Windows) or
. The latter software is preferred since Hyperterminal has a 500-line buffer
limit, but the user may set the maximum buffer size for Tera Term to 10,000 lines.
Both programs allow you to log data to a computer file with no limit on number of data
lines. Using these terminal emulation programs, data may be saved to a text file and
then opened in Microsoft Excel (or other spread sheet program) where it may be
converted to formatted data in columns by defining delimiters (such as commas and
carriage returns) for data manipulation and graphing.
For data transfer the correct settings are: Baud rate = 4800, data bits = 8, parity =
none, stop bits = 1, flow control = note or hardware.
Connect the serial cable to the computer as noted above. From the LCD screen, use
the Select switch to begin operation of the Model 306 to generate ozone or zero air
from the
O3
,
Stp
, or
Zer
menu. (Alternatively, the terminal emulator may be used to
initiate a data stream; see Section 5.2 below.) Serial data lines containing diagnostic
data are output approximately once every second. A typical data line might read:
21,311.6,705.8,4.023,1.43,100,90,1.0001,1
where
21 = Intensity:
This value corresponds to the lamp intensity corrected for
changes in volumetric flow. It will remain steady when
outputting a set value of ozone.
311.6 = T(K):
Temperature in Kelvin of the ozone generator chamber.
705.8 = P(Torr):
Pressure in Torr of the ozone generator chamber.
4.023 = F(L/min):
Flow rate in liters per minute through the generator chamber.
This is the max flow that the connected instrument can possibly
pull.
1.43 = LampDuty:
Duty cycle of the UV lamp creating the ozone (%).
100 = HeatDuty:
Duty cycle of the heater heating the generator chamber (%).
90 = PumpDuty:
Duty cycle of the pump pushing air through the generator (%).
1.0001 = ErrorFrac: Intensity divided by the target intensity.
This value should be between 0.99 and 1.01 for stable operation.
1 = ValveState
Status of Calibration Valve (0 = sample air, 1 = calibration air)
