Command/Property

Description

AcqOn/Off

Start/stop data acquisition.

Delta

Indicates the signal slope, that is, the difference between the current value and the value one second ago; this is useful for Triggers.

EmWavelength

Sets the emission wavelength in nm. The emission wavelength must be at least 20 nm above the excitation wavelength.

ZeroOrder:The grating of the emission monochromator is set to the position of zero order. In this position, the monochromator lets the entire spectrum pass, rather than only a certain wavelength.

ExWavelength

Sets the excitation wavelength in nm. Select the excitation wavelength at the absorption maximum of the sample component to be analyzed.

FilterWheel
(FLD-3400RS only)

Sets the position of the filter wheel for the cut-off filter. Wavelengths under 280 nm, 370 nm, 435 nm, or 530 nm are cut off to suppress stray light. However, in a range of +/- 30  nm around the filter wavelength, some of the light may still pass the filter. The emission wavelength must not be more than 15 nm below the filter wavelength.

Auto: The detector automatically selects the best filter wheel position. Provides the best results for most applications.

Open: The filter wheel remains in an open position. Use this setting if you want to measure with an emission wavelength between 220 nm and 280 nm.

PMT

Determines which photomultiplier tube (PMT) is used for the measurement, if a second, red-sensitive PMT is installed (Dual-PMT).
Auto: Chromeleon will select a PMT.

PMT1: Uses the first PMT (optimized for the UV/Vis region).

PMT2: Uses the second PMT (optimized for the infrared region).

Note: After installation of the Dual-PMT option, you may want to modify any existing PGM files to add this property. Otherwise, the PMT setting stored in the detector from the previous analysis applies.

Retention

Reports the signal's retention time (read-only).

Sensitivity

Selects the detector sensitivity (including the gain for the PMT). Use the maximum expected analyte concentration when determining a sensitivity. Determine the best value by using the MaxPMTSaturation property.

If the sensitivity is too small, the peak height is reduced and the signal-to-noise ratio is poor.

If the sensitivity is too large, the signal is saturated. The detector automatically reduces the sensitivity. Lines that mark the automatic switching appear in the chromatogram at the beginning and end of the saturated range (see figure). Afterward, the original setting is restored.

You can completely turn off fluorescence detection by setting the sensitivity to Off. This may be required, for example, if you want to record the incoming signal from a UV detector for a sample of high concentration, or to suppress an extremely high peak that is not of interest for you but triggers an automatic adjustment of the sensitivity.

Signal

Reports the current signal value [Counts] (read-only).

Command/Property

Description

AcqOn/Off

Start/stop data acquisition.

Delta

Indicates the signal slope, that is, the difference between the current value and the value one second ago; this is useful for Triggers.

Ready

Reports whether the temperature of the flow cell is within the specified limits (Ready or NotReady).

ReadyTempDelta

Sets the maximum allowed deviation from the nominal flow cell temperature. If the value is smaller or greater than the allowed deviation, the detector is not ready for operation (see also Ready). If ReadyTempDelta is set to None, Chromeleon does not check whether the nominal temperature deviates from the actual temperature.

Retention

Reports the signal's retention time (read-only).

Signal

Reports the current signal value [Counts] (read-only).

TempCtrl

Turns temperature control for the flow cell on or off.

Temperature

Temperature of the flow cell. As the fluorescence of a sample decreases as temperature increases, the temperature must not be selected too high, but must be above the temperature inside the detector optics.

Value: Current signal value (read-only)

Nominal: Nominal temperature. Select a temperature that is roughly 15° C above the expected ambient temperature. Note that it is not possible to cool down the temperature below ambient.

None: Turns temperature control for the flow cell off.

Workload

Reports the current workload of the flow cell.

Command

Description

Alarm

Reports a pending leak alarm. Default value: Off.

AlarmOff

Resets a pending alarm and turns off the beep.

Autozero

Performs automatic null balancing (= the current detector signal is interpreted as 0).

BaselineBehavior

Determines how the baseline behaves if wavelengths are switched or the sensitivity or filter wheel setting are changed during a program:

Append: Resets the baseline to the previous signal.

Free: No adjustment, shifts may occur in the baseline position.

Zero: Sets the baseline to zero.

Brightness

Adapts the screen brightness of the detector.

Calibrate

The detector performs a basic calibration by measuring the position of the zero-order lines of both monochromators. Execute if the message "Not calibrated" appears after the detector is turned on.

CalibrateRaman

Performs a wavelength calibration using the Raman bands of water. When you execute the command, a message appears. Ensure that the conditions indicated in the message are met.

ClearAutoZero

Resets the values that were stored during an Autozero command.

ClearDisplayError

Removes a message from the detector display.

ClearMaxPMTSaturation

Resets the value for MaxPMTSaturation to 0%. Execute this command before  MaxPMTSaturation is used to determine the maximum PMT saturation.

Contrast

Adapts the screen contrast of the detector display.

Data_Collection_Rate

The rate [Hz] at which Chromeleon collects digital data from the detector.

Nominal: Sets a Data Collection Rate (only single-channel mode).

Note: The Program Wizard in Chromeleon automatically calculates the appropriate data collection rate, based on the value you enter for the peak width at half-height.

Value: Current value (read-only). The effective data collection rate may differ from the nominal value. For example, if you select a data collection rate higher than 20 Hz and LongLife lamp mode, the data collection rate will be automatically reduced. This property also indicates the value used in multi-channel mode.

DemoFileName

File name of the demo file.

LampMode

Sets the mode of operation for the xenon lamp. A high frequency of flashes results in a lower baseline noise and thus improves sensitivity. At the same time, however, a high flash frequency decreases lamp life:

HighPower – Lamp flashes at the highest frequency.

Standard – Lamp flashes at high frequency resulting in a high sensitivity (not available in multi-channel mode).

LongLife – Lamp flashes at low frequency resulting in a low sensitivity (not available in multi-channel mode). This mode only supports data collection rates up to 20 Hz.

Leak

Reports whether the leak sensor detected a leak (NoLeak or Leak_Detected). If the sensor detects a leak, the running batch is aborted.

LeakSensorMode

Activates or deactivates leak detection.
Enabled (default and recommended): Activates leak detection. A beep alerts you when the leak sensor reports a leak.
Disabled: Deactivates leak detection. No message appears and no beep sounds.

MaxPMTSaturation

Indicates the highest saturation of the PMT signal that was measured since the last reset of MaxPMTSaturation (in percent of the maximum allowable value). Use this parameter to determine and monitor the optimum Sensitivity setting.

- Use the ClearMaxPMTSaturation command to reset the value to 0% before the run.

- Read out the MaxPMTSaturation value after the run.

MultiChannelPerformance (FLD-3400RS only)

Defines whether the measurement in multi-channel mode is optimized regarding signal noise or regarding speed. The UltraFast, and Fast settings result in a higher Data Collection Rate, but also in higher noise, while the LowNoise and UltraLowNoise settings reduce the noise.

MultiChannelResponseTime

Indicates the automatically selected response time in multi-channel mode.

PmtSwitchoverWavelength

Sets the wavelength when the detector switches from PMT1 to PMT2 for a measurement (default: 500 nm). The setting is only available if a second PMT is installed.

RamanValidationInfo

Provides additional information on the previous wavelength verification.

RamanValidationResult

Indicates the result of wavelength validation (passed, failed) or if a Raman wavelength validation should be performed (not validated). See ValidateRaman.

RamanValidationWL

Reports the measured wavelength for the Raman peak. The ideal value is 397 nm.

ResponseTime

The Response Time for the signal. The response time is the time required for the detector signal to rise from 10% to 90% in response to a signal increase.

Select a response time at approximately 1/3 of the peak width at half height of the narrowest peak of interest. The Program Wizard in Chromeleon automatically calculates the appropriate response time, based on the value you enter for peak width at half-height.

SetFactoryDefaults

Restores the Dionex standard settings.

Standby

Sets the detector to standby mode or cancels standby mode. During standby mode, the detector remains connected in Chromeleon.

ValidateRaman

Performs a wavelength validation using the Raman bands of water. When you execute the command, a message appears. Ensure that the conditions indicated in the message are met.

Command/Property

Description

BaseLineScanEmission

Performs a baseline scan with changing emission wavelength.

BaseLineScanExcitation

Performs a baseline scan with changing excitation wavelength.

BaseLineScanSynchronous

Performs a baseline synchro scan with changing excitation and emission wavelength (see ScanSynchronous).

ClearBaseline

Deletes the current baseline spectrum.

ScanEmission

Performs an emission spectrum scan. The result spectrum is stored in a spectra library.

ScanEndEmWavelength

Determines the upper limit of the wavelength range to be scanned during an emission scan.

ScanEndExWavelength

Determines the upper limit of the wavelength range to be scanned during an excitation scan or synchro scan.

ScanExcitation

Performs an excitation spectrum scan. The result spectrum is stored in a spectra library.

ScanFilterWheel
(FLD-3400RS only)

Defines the filter wheel setting during scan mode (see FilterWheel).

ScanPMT

Sets the PMT to be used during scan mode (see PMT).

ScanSensitivity

Sets the detector sensitivity to be used during scan mode (see Sensitivity).

ScanSignalType

Determines if the recorded signal will be corrected regarding the xenon lamp spectrum (ExCorrected) or not (Standard). Standard will provide the best signal-to-noise ratio in method development. ExCorrected will provide best comparability with spectra in the literature.

ScanSpeed

Sets the speed with which the determined wavelength range is scanned. The following settings are available:

ScanStartEmWavelength

Determines the lower limit of the wavelength range to be scanned during an emission scan. Also use this parameter to set the emission wavelength for an excitation scan.

ScanStartExWavelength

Determines the lower limit of the wavelength range to be scanned during an excitation scan or synchro scan.  Also use this parameter to set the excitation wavelength for an emission scan.

ScanSynchronous

Scans a user-defined excitation wavelength range, while the emission wavelength is scanned synchronously with a fixed distance. The distance can be defined under ScanSyncOffset.

ScanSyncOffset

Defines the distance for the Synchro Scan (see ScanSynchronous).

Command/Property

Description

EffectiveLampAge

Provides information about the lamp operating hours to help you in estimating the remaining lamp lifetime.

Indicates how many hours the lamp was operated (read-only). The value is based on the number of lamp flashes. If the value exceeds 4000 hours, the lamp should be replaced. One operating hour is weighted depending on the selected lamp mode:

Example: If the lamp age in Chromeleon indicates 2000 hours, the lamp has reached about the half of its lifetime. Thus, if the lamp is operated in LongLife mode, it is expected to operate for another 8000 hours.

EmGratingMovements/ ExGratingMovements

Counts the movements of the related grating motor (read-only).

FilterMovements
(FLD-3400RS only)

Counts the movements of the filter wheel (read-only).

LastLampChangeDate

Reports when the lamp was replaced last (read-only).

OperatingHours

Counts the operating hours since initial operation (excluding the operating hours in standby mode (read-only).

PMT1Workload/ PMT2Workload

Counts the measuring workload of the related PMT (read-only).

PowerOnTime

Counts the time since last power-up (or last wake-up from standby) (read-only).

PreviousLampEffectiveAge

Indicates the effective lamp age of the previously installed lamp.

Qualification

Provides information about system qualification.

*.LastDate

Reports the date when detector qualification was performed last (read-only).

*.LastOperator

Reports the name of the person who performed the detector qualification (read-only).

*.Interval

Reports the interval (in days) when the next system qualification is due.

*.WarningPeriod

Specifies the period during which a warning appears before the next qualification is due.

*.GracePeriod

Indicates the period during which the device may be operated after the due date for re-qualification.

QualificationDone

Perform this command after qualification to update the related system data.

Service

Provides detector service information.

*.LastDate

Reports the date of the last service (read-only).

*.Interval

Specify the interval (in days) after which a service is due.

*.WarningPeriod

Specifies the period during which a warning appears before the next service is due.

ServiceDone

After the device has been serviced, perform this command to update the related information.

StandbyHours

Counts the total operating hours in standby mode since the module was operated for the first time (read-only).

Property

Description

Analog1_Channel
Analog2_Channel

Sets the signal that is available at the analog output.

Analog1_Offset
Analog2_Offset

Adjusts the zero position of the analog output when it is plotted. The value entered is a percentage of the full-scale analog output. The offset allows the evaluation device to plot the signal if it becomes negative.

 Note: 

The output voltage of the analog outputs cannot reach a minimum of exactly 0 V. Therefore, we recommend to set an offset of at least 5 %, even if only positive analog output signals are expected. This will enable you to also measure very small output signals down to 0 precisely.

Analog1_Range
Analog2_Range

Sets the value range of the analog output signal. The range to use depends on the evaluation device to which the output is connected.

Analog1_Voltage
Analog2_Voltage

Sets the maximum voltage value of the analog output signal (1 or 10). The range to be used depends on the input voltage of the evaluation device to which the output is connected.