PCM-2 Manual.pdf - Voss Associates

Section 3
Operating The Instrument
Normal Operation
When the PCM-2 is not in use, it continually updates background counts on all
detector channels. As this data is collected, dependent variables such as count
times and alarm setpoints are re-calculated. Approximately two minutes are
required to obtain statistically valid beta backgrounds; up to twenty minutes of
background counts are necessary for accurate alpha source detection, however the
PCM-2 will begin to operate as soon as the beta channel backgrounds are valid.
If a hand frisking probe is installed, it may be used during background update. A
display of hand probe readings on the background update screen results when the
hand probe is removed from its cradle on the side of the instrument. This display
disappears when the hand probe is again replaced into its cradle.
When sufficiem beta background data is accumulated, the unit's "traffic lights",
located in the ceiling, change from red to green, indicating that the unit is ready
for measurement. Background counts are halted as soon as a user steps onto the
measuring platform. At this time the PCM-2's user interface becomes active and
a measurement cycle begins. If an optional badge reader is in use, the user may
initiate a measurement by scanning the ID badge either before or after stepping
onto the measuring platform.
If the instrument has been set up to accept user ID and/or radiation work permit
numbers, a message is displayed on the CRT instructing the occupant to provide
this information. These numbers must be no greater than nine (9) characters.
Keypad entry characters must be numeric, whereas badge reader characters may
be alphanumeric. Depending upon the setup options selected, entries may be
made from the keypad, badge reader (if installed) or both.
PCM2.MANI REV AI April '1995
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