Thermo Scientific TVA-1000B Instruction Manual - Geotech ...

MI 611-185 – June 1996
Hardware
WARNING: To prevent a potential explosion, do not operate the instrument with the
PID or FID detector caps removed.
Analog Outputs
The TVA-1000B has two analog output signals, one for each detector (FID and PID). The analog
output cable has a single plug at the instrument end and four individual banana plugs at the output
end. The orange plug is the FID output, the blue plug is the PID output. The two black
plugs are connected to a common ground.
It is important to note that these outputs are non-calibrated outputs which are proportional to the
raw count output signal from each detector. The outputs are not proportional to the PID and
FID dynamic ranges of 0-2000 and 0-50000 ppm.
To calibrate these outputs, it is necessary to measure the output voltage at the time of gas calibration.
When zero gas is introduced to the unit, measure the output voltage for each detector (this
is the zero output voltage). When the span gas is introduced to the unit, measure the output voltage
for each detector (this is the span output voltage).
The output voltage for any other concentration can be calculated with the following formula:
V x = V o + C x [(V s -V o )/(C s )]
where:
V x = Output voltage at the concentration of interest
C x = Concentration of interest
V s = Span output voltage
C s = Span concentration
V o = Zero output voltage
Instrument Sidepack Display
The liquid crystal display (LCD), in the instrument sidepack, as shown in the figure that follows,
has four 16-character lines for three types of displays (MENU, ENTRY, and RUN). In menu displays,
the whole screen is normally dedicated to the menu. In entry displays, the screen provides
prompts and instructions for inputting new data. The normal run display consists of the live measurement
data on lines 1 and 2 and menu items on lines 3 and 4. Other display information
appears as you page through various menus.
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