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Xcalibur Diagnostics for the PDA Detector
Adjusting the Attenuators
Thermo Scientific
Surveyor PDA Plus Detector Hardware Manual
57
Adjusting the Attenuators
The Surveyor PDA Plus Detector has two attenuators that control the light output from the
lamps. During the lifetime of the Surveyor PDA Plus Detector it might be necessary to adjust
the attenuators to increase or decrease the amount of light falling onto the array.
Decreasing light output to the array increases baseline noise. Increasing light output to the
array can cause saturation of the diode array. If the array is saturated, the response from the
Surveyor PDA Plus Detector is a flat baseline.
The attenuators require adjustment when either lamp is replaced or when the flow cell is
replaced. When any of these items are replaced, check the light intensity by following the
Operational Verification procedure and adjust the attenuators to provide light intensities in
the specified operating ranges.
To access the attenuators
1. Open the front doors of the detector.
2. Loosen the captive screw, and then remove the flow cell cover (see
The attenuators are located on the right side of the front panel. There are two black tabs
attached to the attenuators for manual adjustments (see
).
The left tab is the deuterium lamp attenuator and the right tab is the tungsten lamp
attenuator. Pushing the attenuator tab up increases light output and pulling the tab down
decreases light output.
Figure 54.
View of the attenuators
The first time that you adjust the attenuators, you need to create an .spda method. After you
create the method for adjusting the attenuators, save it with a name that you will associate
with adjusting the attenuators and store it for future use. Saving the method will simplify
future adjustments of the attenuators.
Note
Before you adjust the attenuators, replace the column with a flow restrictor, and set
the pump to deliver HPLC-grade water at a flow rate of 1 mL/min through the flow cell.
Deuterium
attenuator
Tungsten
attenuator