User guide

346 Advanced User Guide
11 Valves
Use a run table entry to ensure that the valve is in the Off state
between runs.
Gas sampling valve
If a valve is configured as a gas sampling valve, it starts a run
automatically when it is switched to the Inject position. This
can be done with a keyboard command or by a subsequence or
clock table entry. You may have two gas sampling valves
installed.
Load position The loop is flushed with a stream of the sample
gas. The column is flushed with carrier gas.
Inject position The filled loop is inserted into the carrier gas
stream. The sample is flushed onto the column. The run starts
automatically.
Carrier gas may be provided by an (optional) auxiliary gas
channel. To do this, configure the column and specify an Aux #
channel as the inlet. The channel then becomes programmable
with four operating modes.
Sampling valves have two positions:
Load position The loop (external for gas sampling, internal for
liquid sampling) is flushed with a stream of the sample. The
column is flushed with carrier gas.
Inject position The filled loop is inserted into the carrier gas
stream. The sample is flushed onto the column. The run starts
automatically.
The sampling valve control parameters are:
Carrier in
To c olumn
Sample in
Sample out
LOAD position INJECT position
Loop