Model 405 nm NO
2
/NO/NO
x
Monitor Manual Rev. D
9
well. Be sure to specify the baud rate setting of your data acquisition software to
match the baud rate setting of your instrument. Note that the baud rate of the
instrument may be set to 2400, 4800 or 19,200 as described in Section 4.11 below.
The NO
2
, NO and NO
x
mixing ratios (ppb, pphm, ppm), internal cell temperature (K or
°C), cell pressure (torr or mbar), volumetric flow rate (cc/min), 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 5 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). The
user should separately make note of the instrument settings for units (NO
2
/NO/NO
x
,
temperature, pressure), baud rate and averaging time.
A typical data line might read:
67.4,44.2,111.6,-5,8,30.3,980.6,1576,76.2,1.2743,1.0151,110.2,12/10/15,18:31:27,80
where:
NO
2
= 67.4 ppb
NO = 44.2 ppb
NO
x
= 111.6 ppb
NO
2
_zero = -5 ppb
NO_zero = 8 ppb
Cell temperature = 30.3°C (may be expressed in K if chosen from menu)
Cell pressure = 980.6 mbar (may be expressed in torr if chosen from menu)
Cell volumetric flow rate = 1576 cc/min
O
3
volumetric flow rate = 76.2 cc/min
Sample photodiode voltage = 1.2743 volts
O
3
generator photodiode voltage = 1.0151 volts
Heated scrubber temperature = 110.2°C
Date = October 12, 2015
Time = 6:31:27 pm
Status = 80 (Measuring NO
2
and NO) (see Section 5 for status codes)
If the NO
x
Monitor has been set to the log data mode, the output serial data line will be
preceded by the log number; e.g.,
289,67.4,44.2,111.6,-5,8,30.3,980.6,1576,76.2,1.2743,1.0151,110.2,12/10/15,18:31:27,80
where 289 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 (eh.g., due to a power failure) and when the averaging time is
changed.
