Ce Comments (1590 Only) - Fluke Hart Scientific 1575 Super-Thermometer User Manual

1575/1590 Thermometer Readout
User's Guide
13.2
13.2.1
140
Problem
Graph of measurements shows
jumps or stair-steps and "FILTER
RESET" is displayed
Message displayed, "WARNING:
SUBRANGE EXCEEDED"
When calculating ITS-90 coeffi-
cients, the message "WARNING:
THIS PROBE DOES NOT MEET
ITS-90 SPECIFICATIONS" is
displayed
The display shows negative resis-
tance when the input is shorted
Units displayed
Paramater values entered are not
changing or nothing appears to
happen when pressing ENTER

CE Comments (1590 Only)

EMC Directive
Hart Scientific's equipment has been tested to meet the European Electromag-
netic Compatibility Directive (EMC Directive, 89/336/EEC). The Declaration
Solution
This is normal if the temperature you are measuring is increasing or
decreasing faster than the filter is able to track. To eliminate this effect
you can temporarily disable the filter by setting it to NONE (see Sec-
tion 7.2.4). If this problem occurs when the temperature is reasonably
constant, the filter threshold may be set too low.
This message indicates that the measured temperature is outside the
specified ITS-90 subrange (see Section 7.4.3.2.1). This is to warn you
that the temperature is outside the calibrated range, and thus may not
be accurate. This also serves to warn you that damage to your probe
may occur by operating it at extreme temperatures.
This message warns you that the probe does not completely conform
to the ITS-90 requirements for an SPRT. In order to be used as a pre-
cision temperature reference, an SPRT must be constructed of very
pure platinum wire. The ITS-90 standard requires that the W value for
the SPRT at certain temperatures be within acceptable limits (see
NIST Technical Note 1265, p. 12). When the coefficients are calcu-
lated, the W values are tested and the message is displayed if the
probe does not appear acceptable as an SPRT. This message should
be expected if your probe is an industrial or secondary standards
type. If the probe is a high-quality SPRT and this message appears, it
may indicate there is some error in the data used to calculate the
coefficients.
Though you may expect the reading to be exactly 0Ω when the input
is shorted, electrical noise and limited linearity may cause the reading
to be slightly greater or less than 0. Negative resistance readings can
also be caused by an incorrectly connected probe.
The units displayed can be selected in the Units menu (see Section
7.6.1). If units to be displayed are correct in the Units menu, then the
probe conversion might be set improperly. See section 7.4.3, Edit
Probe, on setting the conversion for a probe that appears to be im-
properly displaying units.
NOTE: The unit in which a measurement is displayed can be affected
by both the conversion type and the System Units settings. Ratio or
ohms settings will override temperature units.
ENTER has to be pressed for all fields to "Enter" the data and commit
it to memory.
Press ENTER twice. Some features require ENTER to be pressed
twice, once to commit the value to memory, and a second time to start
the function/feature being used. Example: When entering a new sam-
ple N value press enter once to accept the new value and then press
enter again to start the sample N countdown.