VTI Instruments Metek EX1202 User Manual page 95

For the RTD's with built-in support, the following Callendar-Van Dusen RTD parameters are
used:
RTD Type
PT100
D100
F100
PT385
PT3916
2-Wire Measurement Connections
A 2-wire RTD measurement is connected in the same manner as a 2-wire resistance measurement.
The HI and LO terminals of the DMM are connected to the RTD's two terminals (no polarity
restrictions).
When using the DMM bus backplane through a switch multiplexer, as shown in Figure 4-16,
observe the common practices introduced in the voltage and resistance measurement discussions
above. Shielding greatly reduces the effect of external interferences/noises. It should also be noted
that the shields should only be connected to ground at one end of the cable and not both.
Basic EX1200 DMM Operation
R = nominal resistance of RTD (resistance at 0 °C)
0
T = temperature in °C
A = α[1+ (δ/100)]
4
B = -αδ/1 x 10
8
C = -αβ/1 x 10 )
Standard
ITS-90
ITS-90
ITS-90
IPTS-68
IPTS-68
Sense HI
Input HI
Input LO
Sense LO
DMM Front Panel
F 4-15: RTD 2-W
IGURE
α β
0.003850 0.10863
0.003920 0.10630
0.003900 0.11000
0.003850 0.11100
0.003916 0.11600
C DMM F
IRE ONNECTION TO
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δ
R
0
100 Ω
1.49990
100 Ω
1.49710
100 Ω
1.49589
385 Ω
1.50700
3916 Ω
1.50594
RTD
P
RONT ANEL
95