Calibrating the Detector (Accela PDA 80 Hz)Detector Control
Calibrating the Detector (Accela PDA 80 Hz)
Chromeleon supports dark current calibration and wavelength calibration for the Accela PDA 80 Hz detector.
To calibrate the dark current:
Manually calibrate the dark current at the following time:
|
When to Calibrate Dark Current: |
After 100 hours of use or monthly, whichever comes first Whenever a significant temperature change occurs After you move the detector After you replace the lamp After a firmware update |
Connect the detector in Chromeleon.
Verify that the lamps are turned on and equilibrated (wait for 1 hour).
Pump methanol through the flowcell at 1 mL/min.
Open the Accela PDA Control Panel and click Calibration to open the calibration subpanel.
Click Start Dark Current Calibration. Before the calibration is executed, a message box appears. Check that the prerequisites shown in the message are met:
The filter wheel is in the OPEN position (position 1).
Both lamps haven been turned on for at least one hour.
The flow cell is filled with methanol.
The methanol is pumped at 1 ml/min.
If requirements are met, confirm by clicking OK. If requirements are not met, click Cancel and prepare the detector accordingly.
Wait until the detector has completed calibration, that is, "Calibration complete" is shown in the Audit Trial. (To cancel the calibration procedure, click Cancel Dark Current Calibration.)
Click Apply Dark Current Calibration to store the new calibration values in the detector. The current date and time are now displayed in the Last Dark Current Calibration box.
Note:
Click Apply Default Dark Current Calibration to reset the calibration to the factory values. Occasionally you need to reset to the default calibration values before performing a new dark current calibration to get calibration values as close to the default as possible.
To calibrate the wavelength:
Wavelength calibration is performed with a peak set of 12 peaks in the UV and visible range. Manually calibrate the wavelength at the following time:
|
When to Calibrate the Wavelength: |
Regularly to correct any misalignment After the detector was sharply jolted. |
Before you perform a wavelength calibration, make sure that the diode array is not saturated (see 
Adjusting the Light Throughput).
Connect the detector in Chromeleon.
Verify that the lamps are turned on and equilibrated (wait for 1 hour).
Pump methanol through the flowcell at 1 mL/min.
Open the Accela PDA control panel and click Calibration to open the calibration subpanel.
Click Start Wavelength Calibration. Before the calibration is executed, a message box appears. Check that the prerequisites shown in the message are met:
The filter wheel is in the OPEN position (position 1).
Both lamps haven been turned on for at least one hour.
The flow cell is filled with methanol.
The methanol is pumped at 1 ml/min.
If requirements are met, confirm by clicking OK. If requirements are not met, click Cancel and prepare the detector accordingly.
Wait until the detector has completed calibration, that is, "Calibration complete" is shown in the Audit Trial. (To cancel the calibration procedure, click Cancel Wavelength Calibration.)
Check that the delta values that are displayed in the Audit Trail are within ±1 nm. If the calibration is ok, click Apply Current Wavelength Calibration to store the new calibration values in the detector. The current date and time are now displayed in the Last Wavelength Calibration box. If the delta values are not within the range of ±1 nm, repeat the wavelength calibration.
Note:
Click Apply Default Wavelength Calibration to reset the calibration to the factory values. Occasionally, you need to reset to the default calibration values before performing a new wavelength calibration to get calibration values as close as possible to the default.
Also, refer to the Accela PDA Detector Hardware Manual.