Thermo Scientific SAM12, Manual

Page: 89 / 176

Issue: 1.0 Operating Instructions
Thermo Fisher Scientific SAM12 User Manual 5-49
This is the normal dormant state
of the system. Normal
Background Monitoring is
continuous until:
1. A door is opened (probably as
part of a measurement cycle) –
see
Door Operations (page 5-51)
for more information.
2. A change in background is
detected – see
Changes to the
Normal Background Monitoring
(page 5-49)
for more information.
3. A high or low background
condition is detected - see
Notes
regarding High Background
(page 5-62)
for more information.
When the SAM12 is not monitoring an article, background is
monitored in 10 second periods, each measurement
contributing to a “rolling average”, produced over a fixed 100
second period, i.e. 10 measurements. Measurements
subsequent to the 10
th
are added to the results store with the
oldest being discarded. In this way, a mean background is
stored and constantly updated for each of the detectors - see
Background Update (page 6-5) for more information.
These values are summed to give an overall mean Background
value for the whole system. Changing or High background
conditions can arise from these checks - see
Notes regarding
Changing Background (page 5-51) and Notes regarding High
Background (page 5-62) for more information.
If a 10 second period is interrupted, for example by opening a
vault door, the current 10 second average will be discarded.
If a change in the Normal
Background Monitoring is
detected, SAM12 will acquire a
new background and the
"Updating Background" message
is displayed.
See
Notes regarding Changing
Background (page 5-51) for more
information regarding acquiring a
background.
Normal Background
Monitoring
Notes regarding Normal
Background Monitoring
Changes to the Normal
Background Monitoring