RTI Piranha, Reference Manual, Page: 82 / 181

4. Measurement Principles & Theory
Update Modes
Piranha & QABrowser Reference Manual 2014-06/5.5C
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radiation. After the reset procedure the Piranha will start to show a value calculated as
the sum of the last X values divided by X (X is the number of seconds chosen by the
user). For each new second that passes the last value in the stack will be discarded and
a new value added. This means of course that it will take X seconds before the Piranha
starts to show a valid value when the detector attached is exposed to a steady radiation
level. In the same way it will take X seconds for the Piranha to show a zero value after
the radiation has ended. Great care must be taken into choosing a time constant fitted
to the nature of the signal.
Example
If you set the time to 8 seconds, each reading, will be the mean of the reading of the last
8 seconds. This means that it will take 8 seconds until the reading reaches a started set
radiation level.
Display Messages and Active Messages 4.4
Even though the range of the Piranha measurement system is quite wide, sometimes
the signal may get too low or too high. To inform you of this, there are display
messages. These are mainly of two types, Active or Passive. Active messages are
shown when the hardware settings can be adjusted to adapt the measurement ranges.
The active message will just inform you that it is making an automatic adjustment and
you can simply do another exposure/measurement. The active messages can be
disabled, see the following section.
The passive display messages indicate what the problem is and possible remedies for
them. These will show if there are no active messages, the active messages are
disabled, or when no more automatic adjustment can be done.
4.4.1 Active Messages
In some rare occasions it might be helpful to disable the active messages, for instance if
the detector signal is very noisy or there are pre-pulses that makes the system auto-
adjust erroneously.
Turning the Active messages to " Off " in
Setup | Preferences does this.
Below the various active messages are shown. Make sure to follow the text shown,
since reset may be performed automatically. Otherwise do a
Reset again.