External Detectors
The epsilon LC detector provides inputs for two external detectors. Analog signals from the external detectors are digitized and processed in a similar fashion to the data from the EC detectors.
CONNECTING THE EXTERNAL DETECTORS
The epsilon detector will accept analog signals of either 0.1, 1.0, or 10.0 volts full scale. Connect the external detectors to the epsilon's back panel as shown here.
CONFIGURING THE EXTERNAL DETECTORS
External detectors are enabled and configured in the Detector Channel Options screen, which is reached as follows:
Open the Data Acquisitions Options screen, either through the Method drop-down menu, or by taking the <<OK or OK>> buttons from other Method screens:
Click the CHANGE button to open the Detector Channel Options screen:
This screen is discussed in depth in the Data Options and Detector Selection section. The following items relate to configuring the external detectors:
FILTER is the noise-reduction filtering to be applied to the data. The optimum filter setting can be determined by measuring signal-to-noise ratio (peak height รท baseline noise) at various filter settings. But for most purposes a value of 0.1 Hz. is adequate. (Large numbers provide less filtering than small numbers.)
If your External Detector has its own filtering, you may disable the Epsilon filtering by setting it to the lowest setting (1.0 Hz.).
RANGE is the full-scale voltage to be expected from the incoming signal. Inputs of 0.1, 1.0, and 10 volts are provided. You should match the input range of the Epsilon to the output range of your External Detector. When in doubt, use a larger range to ensure that the detector's signal does not go off scale.
SCALING THE CHROMATOGRAM
If not specified, the default scale for a single external detector will be Volts (or % Scale, for several detectors). For esthetic reasons you may wish to have the graph scaled in detector units. Proceed as follows:
First, the detector must be properly connected as detailed in the Installation section and configured as detailed above. Scaling will not be correct if the voltage output of the detector and the voltage input of the epsilon system are not matched.
Next, you must have one run in memory. Set the detector to the range you will use and start a run. You need not inject anything.
When the run is complete, take the Graph Data option under the Graphics menu:
For whichever data set corresponds to the external detector(s), change the Full Scale Y value to indicate the range of the detector (e.g., 5 if the detector is set to 5 mAU). Then change the Label Y Units as appropriate (e.g., mAU).
The new scale will remain in effect until changed again, or until you exit and start a new session.
The scaling changes you've entered will be saved with the data files and carried over into Report, so any graphs generated by Report will have the correct detector units as well.
