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2.5 READING THE INSTRUMENT
Set Scale
Slide the calculator between the central retaining clip and the
graduations as shown in Fig. 1.1. Move the scale along until the vertical index
retaining clip is in alignment with the ambient temperature on the temperature
Sect. 2.6 if the material under test is not at ambient temperature.) Fig 2.3
of operations.
Set ZERO
Switch to ZERO. The meter pointer will deflect.
Tum the ZERO knob until the pointer rests at the centre mark.
NOTE:
The 'tens' knob (left-hand BALANCE knob) should not be on
when setting zero. As these are the most sensitive ranges,
atmospheric humidity and effect of electrostatic induction may
be a little unsteady. Switch to any range other than 0 or 1 to
Switch position ZERO is the 'stand-by' position during a series of
Read
The accuracy of the instrument may be checked against the internal standard
required - see Sect. 4.2.
(1)
Having filled the cell, switch to READ.
(2)
Set the units KNOB (the right-hand BALANCE knob) to approximately 0.
(3)
Rotate the tens KNOB (the left-hand BALANCE knob) until the pointer crosses the
centre line on the meter.
(4)
Adjust the units KNOB to bring the pointer to the line. If the reading is on the negative
part of the dial move the tens one step clockwise (unless it is already at 0) and rebalance.
negative section of the dial should never be used if a reading can be obtained on the positive
section.
The figures appearing against the KNOB POINTER marks constitute the dial reading.
Except for readings above 50, little is gained by recording the figure more closely than half a
unit. For readings between 50 and 60
NOTE:
With very low moisture content (i.e. 0 or I positions of the 'tens' dial) the reading
may be a little unsteady due to electrostatic effects.
46882-171 D
Apr. 92
the figure should be determined to one tenth of a unit.
OPERATION
BALANCE scale
line on the central
scale. (See
illustrates the sequence
the 0 or 1 positions
traces of leakage due to
cause the reading to
set zero.
measurements.
resistance if
11
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