Campbell Scientific PVS4100/4120/4150 Portable Automatic Samplers - Manual (Page 74)

Section 5. Programming
5-34
5.6 Programming OTHER OPTIONS
5.6.1 OTHER OPTIONS Overview
SET or VIEW
This feature allows the user to SET or
VIEW the internal Real-Time clock of the
microprocessor.
This feature allows the user to SET or
VIEW the duration for which the sampler
will purge the intake line prior to drawing in
a sample to the chamber. The maximum
allowable setting is 99 seconds.
This feature allows the user to change how
the pinch valve will operate during sampling
cycles. Depending on which generation of
sampler the controller is to be used on
determines the setting. If this is a new unit,
the pinch valve action will have been factory
set. Should the controller be used as a
retrofit into an older model, the setting may
have to be changed. If the sampler has a
pinch valve that squeezes shut the discharge
tube even during an inactive state, this
model is termed as normally closed. Should
the tubing be shut only when the pinch valve
is energized, it is termed normally open.
This is the ONLY setting for the
PVSsamplers.
This feature will enable or disable the ability
of the controller to cease operations when it
encounters repeated difficulties in the
drawing of samples. The controller normally
will attempt to obtain a valid sample by
repetition of its programming with extended
purge times and vacuum cycles, also
extending the time allowed for the
acquisition of the sample. When a sample is
not obtained, this fact is noted in the
controller memory and the program resumes.
If after two (2) successive attempts have
failed, the controller will Shut Down, halting
sampling until operator intervention clears
any reason for fault and RESTARTs the
program. This is not always a required
course of action. If FAULT SHUTDOWN is
disabled, the program will record all failures
to obtain samples and without further