D-2. 375 Rtd - Fluke NetDAQ 2640A User Manual

Using the Custom-385 RTD with Other Platinum RTDs
Although the Custom-385 RTD linearization uses a
other RTD types can be used. The Custom-385 linearization will compensate for
the change in , but errors will be introduced due to the difference in the and
coefficients of the RTD and the fixed coefficients. Figure D-2 shows the accuracy
envelope for a 375 RTD. Because of the error introduced by the approximation
and the difference in it is recommended that the use of the 375 RTD be limited
to temperatures between -100 C and 300 C. Figure D-3 shows the accuracy
envelope for a 391 RTD and Figure D-4 shows the accuracy envelope for a 392
RTD. Due to errors introduced by the approximation and the difference in it is
recommended that the use of the 391 RTD and 392 RTD be limited to
temperatures between -100 C and 600 C.
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-100
Accuracy Envelope: Custom RTD, 375 Probe
1 Year Slow: 18-28 Degrees C
Alpha: 0.00375 Delta: 1.605 Beta: 0.16
2645A
2640A
-50 0 50
Temperature - Degrees C
Figure D-2. 375 RTD
and from a 385 RTD,
100 150 200
RTD Linearization
D
Custom-385 RTD
D-4.
250 300
D-3