Varian Micro-GC 490-GC, User Manual

Page: 50 / 83

Reference
Page 42 User Manual Micro-GC Varian, Inc.
A complete instrument, the DMD consists of a basic cabinet, a column module with its
pneumatic system, its standard µ-TCD and an additional DMD. The standard channel’s
µ-TCD output is in series with the DMD inlet via a heated transfer line. The temperature
of this heated transfer line is controlled from the DMD electronics.
From a control point of view, the DMD has no control of a column temperature or
column head pressure or the optional injector temperature as needed for the GC
channel. No carrier gas type needs to be selected in the configuration.
Furthermore, the DMD method is factory tuned and ready to perform the appropriate
application. This requires the Micro-GC method to be identical throughout its use with
respect to chromatographic column and settings.
GENERAL OPERATION
Within the workstation package, the DMD will be handled as a separate channel. With
respect to the operation of the DMD note the following:

In instrument configuration, selection of carrier gas type and heated injector has
been removed.

In method development for the DMD channel, GC-channel specific information has
been left out. Instead, the Transfer line temperature and the detector tuning
capabilities are added.

In instrument status for the DMD channel, GC-channel specific information has
been left out. Instead, the Transfer line temperature and the detector tuning
capabilities are added.
Tuning the DMD
The complete DMD method for the instrument specific application has been tested and
is loaded inside the DMD. Generally no modification or changes are required in case
the factory-supplied method is used throughout.
In case of a suspected misalignment of the method, where retention time or
compensation voltage may be out of tune, a tuning run may be needed.
Please contact for more information your local Varian Inc. subsidiary or Varian, Inc.
representative.