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

Page: 33 / 120

Measuring Temperature
IEC751
Selecting IEC751 from the standard menu selects the standard
coefficients from IEC751 (DIN43760/ BS1904 -based on IPTS68).
The coefficients for IEC751 are as follows:
Ro A B C
IEC751 100 Ohms 3.90802 x 10
-3
-5.802 x 10
-7
- 4.2735 x 10
-12
EN751
Selecting EN751 from the standard menu selects the standard
coefficients from BS EN60751 based on ITS90. The advantage of this
is that it removes the temperature conversion errors associated with
the old IEC751 standard which is based on the earlier and
superseded IPTS68. The coefficients for EN60751 are as follows:
Ro A B C
EN60751 100 Ohms 3.9083 x 10
-3
-5.775 x 10
-7
-4.183 x 10
-12
US/JIS
Selecting US/JIS from the standard menu selects the standard
coefficients from JEMIMA for high alpha PRT reference
thermometers. The coefficients for US/JIS are as follows:
Ro A B C
JIS/US 100 Ohms 3.97478 x 10
-3
-5.8775 x 10
-7
-3.4813 x 10
-12
Usr
Selecting Usr from the standard menu allows the coefficients
provided with calibrated PRTs to be used in converting resistance to
temperature.
Either 25 or 100 Ohm SPRT’s/RTD’s may be used and coefficients for
ITS90 or Callendar Van Dusen entered. The instrument recognises from
data entered under Ro if a 25 or 100 Ohm probe is being used and
automatically adjusts the measuring range and measuring current.
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