14
CHAPTER 2. GETTING STARTED
If at any time the instrument fails to read within 20% of the reference reading when using
the dedicated check source, it should be removed from service and sent to a calibration fa-
cility for recalibration and/or repair. If desired, multiple readings may be taken at different
distances and/or with different sources so that other scales are checked.
Example of a Check Source reading:
Check Source #
Rate
Units
2.4 Detector Failure Diagnostics
Note that the Model 3002 has its own diagnostic tests to ensure that the detector is function-
ing correctly.
2.4.1 Detector Loss of Count
If the detector stops detecting radiation for a settable number of seconds, the Model 3002
will flash the display and the LED for the specific radiation type to indicate a fault while
emitting an audible alarm. If the detector stops detecting alpha or beta radiation for a set-
table number of seconds (loss of counts), the failing type of radiation will flash a zero reading
for the currently selected radiation type, and the alpha+beta channel will flash the current
value. This indication is common if the unit is powered up without a detector connected. If
this indication is observed with a connected detector, remove the unit from service and have
it evaluated by a qualified repair and calibration technician.
Figure 2.5: Detector Loss of Count Display-Alpha (Display Will Flash)
2.4.2 Detector Over Range
If the detector is exposed to high levels of radiation or has an internal malfunction that
causes it to count high or excessively, the unit flashes the maximum display value for the
currently selected radiation type as a warning. Additionally, the ALARM icon is displayed at
the top of the screen, an audio alarm sounds (which can be silenced by a long press of the
ON/OFF button ), and the device status OVERRANGE is streamed or logged. The user should
ensure whether this condition is being caused by a high radiation field, by a shorted cable,
or by internal malfunction. If a Maximum Display parameter is set, then it is possible for the
display to flash the Maximum Display value under this condition.
Ludlum Measurements, Inc.
