Section 3: C ontrols and Adjustm ents
Airmetrics
13
3 CONTROLS AND ADJUSTMENTS
All Operating Modes
The following controls (see Figure 3.1) are used to set the operation of the
MiniVol in both the particulate matter sampling mode and the gas sampling mode.
E
LAPSED
T
IME
T
OTALIZER
The Elapsed Time Totalizer displays the total number of hours, with a resolution of
tenths of h ours, that th e pum p has run . The totaliz er accum ulates tim e only w hile
the pump is running. It cannot be reset to zero. The total hours should be recorded
at the beginning and end of each sampling period.
P
ROGRAMMABLE
T
IMER
The Programmable Timer controls the on/auto/off operation of the sampler. The
timer allows up to six sampling tim es to be preprog ramme d over twenty -four hours
or throughout a w eek (see "Prog ramming the Timer").
F
LOWMETER
The Flowmeter indicates the flow rate of air through the system in liters/minute.
The flow rate is adjusted using the "Flow Rate Adjustment".
The flow meter rea dings m ust be take n from th e center o f the ball.
F
LOW
R
ATE
A
DJUSTMENT
The Flow Rate Adjustment potentiometer (knob) varies the sampler's flow rate as
indicated by the lev el of the ball (read from the center of the ball) in the flow meter.
Slowly turn the k nob until the air flow rea ches the desired lev el. The samp ler's
Flow Control Circuit will attempt to maintain this flow rate by varying the speed of
the pump a s particulate matter acc umulates on the filter.
Airmetrics MiniVol Users Guide
14
Airmetrics
Figure 3.1.
Sampler Controls and Adjustments
12V
B
ATTERY
P
OWER
C
ONNECTOR
The 12 V Batter y Pow er Conn ector is a sta ndard ph one plug -in jack w hich con ducts
power from the battery to the sam pler.
L
OW
F
LOW
T
HRESHOLD
I
NDICATOR
The Low Flow Threshold Indicator light is activated when the flow sensor
determ ines that the air flow rate has drop ped som e increm ent below the flow ra te
