Operation
Diagnostics Menu
3-64
Model 48
i
Instruction Manual
Thermo Fisher Scientific
PRESSURE: 753.0 mmHg
RANGE AVG DIAGS ALARM
The Flow screen (read only) displays the flow rate. The flow is measured by
an internal flow sensor. For more information, see Chapter 1,
“
Introduction
”.
●
In the Main Menu, choose Diagnostics >
Flow
.
FLOW: 1.108 L/min
RANGE AVG DIAGS ALARM
The Sample/Reference Ratio screen (read only) displays the ratio of the
intensities of the light source through the sample wavelength and reference
wavelength of the bandpass filter wheel. Normally, when zero air is being
sampled, the sample/reference ratio is between 1.14 and 1.18. A ratio
outside may indicate that the filter wheel is dirty or the infrared source is
degraded.
●
In the Main Menu, choose Diagnostics >
Sample/Ref Ratio
.
SAMPLE REFERENCE RATIO:
S/R: 1.161111
RANGE AVG DIAGS ALARM
The AGC Intensity screen (read only) displays the intensity (in Hertz) of
the reference channel Automatic Gain Control (AGC) circuit. The AGC
circuit optimizes the noise and resolution levels of the Model 48
i
. The
AGC intensity reading should be about 250,000 Hertz.
Flow
Sample/Reference
Ratio
AGC Intensity