Sigma 900 MAX Refrigerated Sampler Instrument Manual

Page 20
Principle of Operation
8990int.fm
Section 1
Intake Tube Pre-Rinse
The liquid sensor also rinses the intake tubing with the liquid from the sample
source before taking each sample.
Upon sample initiation, the pump purges the intake line. The pump then
reverses, pulling liquid through the tubing, until it reaches the liquid sensor.
When the sensor detects liquid, the pump purges back to the source, and
then draws a sample. After the desired sample is collected, the pump purges
the intake line and awaits the next sample cycle. The sampler can be
programmed for up to 3 rinses before each sample.
Sample Retry
The liquid sensing system permits the sampler to repeat a collection cycle if a
sample is not obtained during the regular cycle.
The intake line length is user-programmed into the sampler memory. For a
line length of 3 to 99 feet, the sampler has a built-in “look up” table that
detects the maximum time required for liquid to reach the sensor. If liquid
does not reach the sensor within the defined time period, the pump will
automatically purge the intake line and initiate another sample cycle. The
sampler may be programmed for up to three repeated attempts. If a sample is
not obtained, the sampler retains in memory the time, date and reason for the
missed sample.