User guide

Methods and Sequences 5
Advanced User Guide 111
Creating Sequences
A sequence specifies the samples to be run and the stored
method to be used for each. The sequence is divided into a
priority sequence (ALS only), subsequences (each of which uses
a single method), and post- sequence events
• Priority sequence—allows you to interrupt a running ALS or
valve sequence to analyze urgent samples. (See “About the
priority sequence” on page 111.)
• Subsequences—contain the stored method number and
information that defines a set of samples and calibrators to
be analyzed using a particular method. Sampler and/or valve
subsequences can be used in the same sequence.
• Post sequence—names a method to be loaded and run after
the last run in the last subsequence. Specifies whether the
sequence is to be repeated indefinitely or halted after the
last subsequence.
Samples in each subsequence are specified as either ALS tray
locations or sampling valve positions (gas or liquid sampling
valves, often with a stream selection valve).
Five sequences with up to five subsequences each can be stored.
About the priority sequence
The priority sequence consists of a single sampler or valve
subsequence and a special Use priority parameter, which can be
activated at any time, even when a sequence is running. This
feature allows you to interrupt a running sequence without
having to edit it.
If Use priority is On, then:
1 The GC and ALS complete the current run, then the sequence
pauses.
2 The GC runs the priority sequence.
3 The GC resets the Use priority parameter to Off.
4 The main sequence resumes where it paused.
To program a sequence
1 Press [Seq]. (Press again, if necessary, to display
subsequence information.)
2 Create a priority sequence, if desired. (See “To program a
priority sequence” on page 112.) If you might want to use a