Fluke Biomedical 440RF - Manual (Page 9)

Operation
Controls and Indicators
2
2-1
Section 2
Operation
2.1 Controls and Indicators
Function/Range Switch
Function/Range Switch positions include OFF, BAT, 100, 30, 10, 3 and 1 (Model 440RF/D) and OFF,
BAT, 1000, 300, 100, 30 and 10 (Model 440RF/D-SI). The rotary switch is located below the handle. It
turns the instrument OFF, provides a battery check function, and provides five operating ranges in mR/h
or μSv/h, depending on user preference. The BAT position is also used with the communication option.
Refer to Specifications, Section 1-2 for a list of operating ranges.
Zero Adjust
The Zero adjust, a screw centered just below the meter scale, zeroes the meter needle.
Meter
A panel meter, located on top of the instrument, displays the exposure rate (mR/h), dose equivalent rate
(μSv/h), or battery condition.
Check Source
The check source, a hexagonal spring-loaded rotary switch positioned next to the chamber, verifies
instrument operability.
2.2 Power, Battery Check, and Range Changing
A single rotary switch, located beneath the carrying handle provides function/range capability. In the OFF
position, the 9 V electronic power supply is disconnected. The switch should be returned to the OFF
position whenever the instrument is not in use to extend the battery usage period and to prevent possible
damage to the battery compartment due to leaking or spent cells. Any other switch position will cause full
battery current drain. If the instrument is placed in operation after a period of idleness, place the
function/range switch in the BAT position and remain there. The function of the BAT position is to monitor
the condition of the 9 V electronic supply and the -18 V chamber supply. This is accomplished through
measuring the voltage (using the microprocessor) provided by the divider circuits directly across the
battery supplies.
If both sets of batteries are at the voltages required for operation when the instrument is placed in the bat
position from the OFF position, the meter should indicate full scale (9 V electronic supply), then drop to
approximately half-scale (-18 V chamber supply), then return to the full scale position. If the instrument is
in operation and battery check is performed, the meter will just indicate a full-scale reading. If either set of
batteries is not at the voltage required for operation, the meter will drop to 0 V.
If the meter reads 0 V in the bat position, remove the batteries (one set at a time) and test them using a
voltmeter to determine which batteries are bad. Replace the complete set for chamber voltage or
electronic supply once the batteries have been located. Refer to Figure 2-1 for battery compartment
location.