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

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Introduction
1.3.2 Thermocouple measurement
As well as the PRT resistance measurement facility the TTI-7-R also
functions as a precision milli-voltmeter. Designed for high accuracy
measurement over the EMF voltage range of all standard base and
precious metal thermocouples, the TTI-7-R achieves a basic voltage
accuracy of better than 3µV
(at +20 °C ±2 °C) over the full measurement range and significantly
better over smaller ranges. See Section 9.2 for thermocouple
measurement performance details. Thermocouple EMFs are
converted to temperature using the NIST monograph 175
linearization functions. Special types C and D use the linearizations
specified by ASTM E988.
The voltage input connection is specially designed to minimise the
thermal gradient between the terminals. This is particularly important
when the internal reference junction compensation is used, as any
temperature difference at the connection junction will influence the
measurement result. The connection junction is introduced in
Section 1.3.3 below.
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