Functional Description - Emerson Daniel Danalyzer 1000 Hardware Reference Manual

MODEL 1000
SEP 2005
1.3

FUNCTIONAL DESCRIPTION

A functional block diagram of a typical GC System installation is shown in Figure 1-1. A sample
of the gas to be analyzed is taken from the process stream by a sample probe installed in the process
line. The sample passes through a sample line to the sample conditioning system where it is filtered
or otherwise conditioned. After conditioning, the sample flows to the Analyzer for separation and
detection of the components of the gas.
The chromatographic separation of the sample gas into its components is accomplished in the
Analyzer in the following manner. A precise volume of sample gas is injected into one of the unit's
analytical columns. The column contains a stationary phase (packing) that is either an active solid
(adsorption partitioning) or an inert solid support that is coated with a liquid phase (absorption
partitioning). The gas sample is moved through the column by means of a mobile phase (carrier
gas). Selective retardation of the components of the sample takes place in the column that causes
each component to move through the column at a different rate. This action separates the sample
into its constituent components.
A detector located at the outlet of the analytical column senses the elution of components from the
column and produces electrical outputs proportional to the concentration of each component.
Outputs from the Analyzer detectors are amplified in the Analyzer electronics, then transmitted to
the GC Controller for further processing. (See also, Section 1.6, "Theory of Operation.")
Output from the GC Controller is normally displayed on a remotely located personal computer (PC)
or a printer. Connection between the GC Controller and the PC can be accomplished via a direct
serial line or via the Modbus-compatible communication interface.
Multiple chromatograms may be displayed on the PC monitor, and compared or contrasted with
separate color schemes. This allows a stored chromatogram to be compared/contrasted with a
current or another stored chromatogram. This could be of great assistance when changing
parameters or isolating a problem.
Use of a PC for configuration and troubleshooting procedures is essential in most instances. (Basic
operations can also be performed from a keyboard and liquid crystal display that are built into certain
versions of the GC Controller.) The PC may be remotely connected via telephone, radio or satellite
communications. Once installed and configured, the GC System can operate independently for long
periods of time.
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DESCRIPTION