Give the optical unit enough time to warm-up and stabilize (> 60 minutes). The detector is temperature controlled. After turn-on of the detector, it goes through a cycle of different states:
0 to 0.5 minutes the heater control is OFF and the heater element runs at 0 % duty cycle.
0.5 to 1 minutes the heater control is OFF and the heater element runs at 66% duty cycle. This first minute is used as self-test of the heater functionality.
1 to 30 minutes the heater control is OFF and the heater element runs at 40% duty cycle.
After 30 minutes the heater control is ON and is working with optimized parameters to get the optical unit into the optimal temperature window stabilized.
This cycle starts
when the detector is turned off/on
when the lamp is turned off/on
to ensure that the temperature control operates in a defined control range.
NOTE
The times to stabilize the baseline may vary from instrument to instrument and depends on the environment. The example below was done under stable environmental conditions.
The figures below show the first two hours of a detector warm-up phase. The lamp was turned on immediately after turn on of the detector.
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