Waters 2414, Обзор и руководство по обслуживанию

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June 11, 2015, 715004754 Rev. A
Page 33
Higher time-constant settings produce these effects:
• Greatly decreased baseline noise
• Shortened and broadened peaks
The default time constant of 1.0 second in Hamming mode is satisfactory for most
applications. To calculate an appropriate time (filter) constant for special applications,
use the formula:
TC = 0.2 * PW
where
TC = Time constant (filter) setting
PW = Peak width at half the height of the narrowest peak
1.3.7.2 Polarity
Detection peaks can be positive or negative. You must configure and change the
polarity of the detector signals while acquiring data. Use the Polarity parameter to
invert the sign of the RI data. A positive polarity leaves the data unaffected; a
negative polarity essentially multiplies the value of each data point by –1, inverting
the chromatogram. Polarity affects the analog output, front panel display, and
chromatography data software .
Polarity can be set or changed from various places: front-panel key press, remote
interface command, rear panel event input (Polarity 1), or timed event. Polarity can
be thought of as a bimodal state (either positive or negative) that can be changed by
an external event trigger.
If an event occurs to change Polarity while Polarity 2 is TRUE, an appropriate error
message appears. For instance, a front-panel key press causes a warning message to
appear on the front panel display, and a Remote command prompts a warning status.
1.3.8 Temperature control
The detector oven, which controls the temperature of the flow cell, has a temperature
setting range of 30 to 55 °C, in increments of 1 °C. The detector oven temperature
set point and actual temperature reading is accessible via the front panel’s display
and the remote interface. The actual reading resolution of the detector oven
temperature, on the front panel, is ±0.5 °C.
The automatically resettable switch protects the oven temperature from raising above
the set point, interrupting power to the heater when the thermal limit is exceeded.
The switch resets when the oven temperature cools to a safe operating level.
1.3.8.1 Column heater module temperature control
The 2414 RI detector controls an external column heater module through the rear
panel’s column heater connection. The column heater temperature setting range is 30
to 150 °C, in increments of 1 °C. You monitor the set point temperature while the
actual temperature reading is accessible via the detector’s front-panel display and the
remote interface. The actual reading resolution of the column heater module, on the
front panel, is 0.1 °C.