wtw Turb 555, Руководство по эксплуатации

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Turb 555 / Turb 555 IR Operation
37 ba41113e07 04/2009
4.4.2 Calibration procedures
You have the following possibilities to calibrate the Turb 555
/Turb 555 IR:
z Five-point calibration according to the preset calibration
program (section 4.4.4). To achieve the accuracy speci-
fied in the Technical Data in the whole measuring range
you have to carry out this calibration.
z
User-defined calibration over a limited interval (section
4.4.5).
z Single-point calibration. This is a special user-defined cal-
ibration and only to be recommended as a temporary so-
lution. The calibration timer is not reset. After a single-
point calibration, measuring is only possible near the cal-
ibration point and with reduced accuracy.
Note
For measurements according to DIN/ISO or Standard Meth-
ods, it is absolutely necessary to calibrate with Formazin.
For more information, see application report 998 255 P
RE
-
PARATION OF
F
ORMAZIN PRIMARY STANDARD
.
Calibration points
and measuring
ranges
For an optimum calibration over the whole measuring range
of the instrument, you need the following five calibration
standards:
z 0.02 NTU
z 10 NTU
z
100 NTU
z 1750 NTU
z
10000 NTU (available as accessory,
see chapter 8 A
CCESSORIES
, O
PTIONS
)
You can also calibrate with less than five calibration stan-
dards if the measured values expected are in a limited
range. When selecting the calibration points, however, the
following rules have to be observed:
z The measuring range to be expected must be between
two calibration points.