Isotech TTI-7-R, Operator'S Handbook Manual

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Measuring Temperature
4.4.1 PRT linearization functions
The TTI-7-R provides 3 standard and 20 user definable algorithms
for converting resistance to temperature. The choice will depend on
the type of PRT and its calibration. See also Section 9, which gives
PRT sensor information.
IEC751 (1983):- used for un-calibrated industrial PRTs with
0.003850 "alpha" value, to provide a conversion of resistance to
temperature in accordance with the IEC751 (IPTS 68) standard.
• EN60751 (1992):- used for un-calibrated industrial PRTs with
0.003851 "alpha" value, to provide a conversion of resistance to
temperature in accordance with the
BS EN60751 (ITS 90) standard.
• US/JIS:- used for un-calibrated industrial PRTs with 0.003916
"alpha" value, to provide a conversion of resistance to
temperature in accordance with the JEMIMA standard.
Un-calibrated PRTs conforming to IEC751/DIN43760/BS1904 have
traditionally used the IEC751 pre-programmed standard, which
provides a conversion in accordance with published DIN43760 or
BS1904 tables. These tables were created using temperatures
defined by the superseded International Practical Temperature Scale
of 1968 (IPTS68) and have inaccuracies compared with the
International Temperature Scale of 1990 (ITS-90). ISOTECH NA Inc.
has included the values for standard coefficients from IEC751 and
the more recent
EN60751 standards. The use of EN60751 is now recommended for
use with uncalibrated industrial PRTs.
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