19
7. Calibration (Scale adjustment)
Seeing the field of refraction view, the
colored boundary line is observed near
the intersection of the cross hairs. Turn
the
color
compensator
knob
to
achromatize the boundary line, and stop
turning when the boundary line becomes
neither reddish nor bluish. Since reddish
edge appears just above the boundary
line while bluish edge appears just below
it, the midpoint where neither reddish
edge nor bluish edge appears indicates
that the color is completely compensated.
c)
Turn the measurement knob again so
that the scale reads 1.3330 (When the
temperature is other than 20
Υ
, the scale
must read the Refractive Index at the
actual temperature) and Brix0.0%. Adjust
the calibration screw located in the center
of the calibration section with the special
screwdriver supplied as an accessory so
that the boundary line appearing in the
field of refraction meets the intersection
of the cross hairs (Fig. 7-6).
d)
Note:
When the measurement temperature is other than 20
Υ
, adjust the scale indication
to correspond to the Refractive Index at the actual measurement temperature
referring to the following table.
Relation between temperature and Refractive Index (nD)
Temperature
Temperature
Refractive Index
Refractive Index
Υ
Υ
nD
nD
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
1.33369
1.33364
1.33358
1.33352
1.33346
1.33339
1.33331
1.33324
1.33316
1.33307
1.33299
1.33290
1.33280
1.33271
1.33261
1.33250
1.33240
1.33229
1.33217
1.33206
1.33194
1.33182
1.33170
1.33157
1.33144
1.33131
1.33117
1.33104
1.33090
1.33075
1.33061
