Sample Delivery To Reaction Tray; Sampling Mechanisms - Siemens ADVIA 1800 Operator's Manual

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Liquid level sensing and short sample
The liquid level sensor on the sample-dilution probe (DPP) and the reagent probes (RPP1
and 2) detect the level of liquid. The system then monitors that the probe remains in liquid
during the entire aspiration. If there is insufficient liquid, the system alerts the operator in
the alarm message line and posts a flag for short sample or insufficient reagent.
Crash detection
Crash detection is a feature that detects an obstruction in the vertical movement of the
DPP probe. If the probe encounters an obstruction, it springs back slightly causing an alert
to be posted in the alarm message line. The system also posts a flag and sampling stops.

Sample delivery to reaction tray

At initialization, the SPP moves (in the up position) to the RRV cuvette, then stops above
the wash port. The pumps stop when the SPP is over the RRV cuvettes.
Each sampling cycle consists of these steps:
1. The SPP moves to the aspiration position of the DTT and aspirates the sample.
2. The SPP moves back to the wash port, where deionized water washes the SPP's
outside surface.
3. The SPP moves to the RRV and dispenses the sample into a cuvette.
4. The SPP returns to the wash port, where degassed water washes the inside and exterior
of the SPP.
5. The SPP is now ready for another cycle.
If an assay is not running, you can operate the unit manually at the Manual Operation
window.

Sampling mechanisms

The sample probe (SPP) aspirates sample from the dilution tray (DTT) and dispenses it
into reaction tray (RRV) cuvettes for analysis, according to specified conditions. The
sampling pump (SP) handles the aspiration and dispensing functions.
28 ADVIA 1800 Operator's Guide