PL-GPC 220 User Manual 37
Using the Module
4
The Graphical User Interface
RI Configuration Editor
The Refractive Index Detector can be programmed to automatically zero at
regular intervals during an autosampler sequence. Setting the Autozero cycles
to 1 will cause the instrument to autozero before each sample injection.
Similarly, the refractometer can be purged at regular intervals during an
autosampler sequence by programming the Cycles field in the Purge section of
the Configuration Editor. However, the suitability of this operation is
application dependent and it may only be useful in some circumstances (e.g.
using 1-chloronapthalene at 210 °C).
The Duration of the purge is simply the time in seconds that the purge valve will
remain open following a manual or automatic purge command.
The Settle Time is the time allowed in seconds following a purge that the system
waits before the autozero command is actioned if an Automatic RI Conditioning is
enabled.
Purging and zeroing the refractometer are typically executed manually
following stabilization of the oven temperature when the temperature is
changed or when the instrument is switched from Idle to Run. However, by
checking the Automatic RI Conditioning box the system can be programmed to
automatically purge and autozero the RI, 10 min after the oven set point is
reached, in accordance with the parameters programmed in this dialog. The RI
Limits value is used as the baseline stabilization threshold, and the system will
continue cycling between purging, zeroing and monitoring until the baseline
drift is less than the programmed limits measured over a 10 min period.