Some Specifics; Gas Control; Columns; Inlets And Detectors - Agilent Technologies 6890 Series Operating Manual

The 6890 Series Gas Chromatograph

Some specifics

Some specifics

Gas control

The GC can control all gas streams—inlets, detectors, and three auxiliary
flows—from the keyboard using Electronic Pneumatic Control (EPC). EPC
allows flow and pressure setting plus a variety of program modes.
Some nonEPC inlets and detectors are also available. They function in the
conventional manner using flow controllers, pressure regulators and a separate
flow meter. Only on/off control is available from the keyboard.

Columns

You can control the behavior of the carrier gas in the column, specifying constant
or ramped flow or constant or ramped pressure. EPC inlet systems maintain this
behavior for the entire run, even with temperature programming.
The column should be set up before the inlet!

Inlets and detectors

These are covered in the separate Inlets and Detectors volumes.

Signals

Signals are the data streams that exit the GC for processing by some other device.
There is a wide selection, both analog and digital.

Automation

The run time table executes commands at specified times after injection. The
clock time table executes commands at specified times of day.

Methods and sequences

The active method is the set of control tables and values that is presently
controlling the GC. Up to five methods can be stored in memory.
A sequence is a list of sample locations and the stored methods to be used to
run them. Up to five sequences can be stored. Samples may come from either
an automatic liquid sampler or a sampling valve with a stream selector valve.
Sequences can be interrupted to run urgent samples.
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