Ludlum Measurements 3100, Руководство пользователя

Страница: 17 / 57

2-2
Figure 2-1. Identification of Controls.
2.2.1.1 Backlight Switch.
This is a 295-degree rotary control that adjusts backlight intensity for minimum or
maximum lighting contrast.
2.2.1.2 ACK/RESET Switch.
Under alarm conditions, the first press of this button acknowledges (silences) the
alarm audio, but maintains the “Alrm” text on the display. Once the radiation activity has decreased below the preset
level, the second press resets the displayed alarm on the display. When in the CHECK mode, the ACK/RESET is
used to toggle between the first check screen and the second check screen (see Section 2.2.1.4b).
2.2.1.3 Airflow Desiccant IN-LINE/OFF-LINE Switch.
Located on the back side of the instrument, this toggle
switch switches the desiccant in-line with the input airflow or allows the incoming airflow to bypass the airflow
desiccant.
2.2.1.4 Mode Switch.
This is a five-position rotary switch marked OFF, CHECK, MEASURE, SAMPLE
(PUMP ON), and PURGE.
a. OFF means the unit is turned off. Note that in this position the internal batteries are not being recharged,
even if the mains power cord is connected.
b. The CHECK mode displays the results of several automatic measurement diagnostics. Diagnostic results
that are within tolerance are marked with a check mark, while out-of-tolerance measurements or conditions
are marked with the letter “X.” By pressing the ACK/RESET button, the second CHECK mode screen
labeled “Check Test” will be activated. This mode is meant to check the electrometer and amplifier and
provides a preset bias to the tritium chamber, generating a repeatable reading if internal voltages and the
amplifier are working correctly. This preset bias may be disabled during calibration, if desired, so that an
external gamma check source may be used instead to perform the same check. If so, then a gamma source
is placed on the instrument can at the tritium detector to obtain a repeatable and consistent reading.
c. The MEASURE mode allows the unit to measure already-sampled air inside the chamber, without the
pump running. Note that the response time is approximately 60 seconds. This is the recommended mode to
charge the internal batteries.