GW Instek GOM-802 User Manual User Manual
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GOM-802 DC MILLI-OHM METER
USER MANUAL
⎯ ⎯
28
7-2. Temperature measurement
(1) Reference temperature
The international Temperature Scale (ITS) is based on the following
table 7-1 which was revised in 1990 with seventeen fixed points and
corresponding temperatures.
Table 7-1:
Temperature
Element
Type
K
℃
(H
2
)
(Ne)
(O
2
)
(Ar)
Hydrogen
Neon
Oxygen
Argon
Tripple point
13.8033
24.5561
54.3584
83.8058
-259.3467
-248.5939
-218.7916
-189.3442
(Hg)
(H
2
O)
(Ga)
(In)
Mercury
Water
Gallium
Indium
Tripple point
Tripple point
Melting point
Freezing point
234.325
273.16
302.9146
429.7485
-38.8344
+0.01
29.7646
156.5985
(Sn)
(Zn)
(Al)
(Ag)
(Au)
Tin
Zinc
Aluminum
Silver
Gold
Freezing point
505.078
692.677
933.473
1234.93
1337.33
231.928
419.527
660.323
961.78
1064.18
Note: 1. Temperature unit:
Thermodynamic temperature:
T
Kelvin:
K
2. Temperature scale:
Celsius scale: ℃
Rankinescale:
°R
Kelvin: ℉
℃ =5/9 (℉-32)
K = ℃+273.15
°R =
℉+459.67
GOM-802 DC MILLI-OHM METER
USER MANUAL
⎯ ⎯
29
(2) Temperature measurement sensor
The common usage for the resistance temperature detectors, RTD, is to
convert temperature into electro signal. Please refer to following table
7-2 of its feature:
Table 7-2
Feature
Description
1. Accuracy
Higher accuracy
2. Resolution
0.1~1.0℃ higher resolution
3. Speed of response
Slower
4. Self-heating
yes
5. Long term stability
Good
6. Output characteristic
Approx. 0.4 ohm/℃, near linear.
(3) Optional Platinum resistance sensor
This kind of temperature probe meets the specification of German
DIN43760: 1968, 3-wire measurement.
The relation between temperature and resistance can refer to the
description of the Gallendarvan Dusen Equation as follows:
R
RTD
=R
0
[1+AT+BT
2
+CT
3
(T-100)]
Where: R
RTD
is the calculated resistance of the RTD.
R
0
is the known RTD resistance at 0℃.
T is the temperature in ℃.
A=alpha [I+(delta/100)]
B=-I(alpha)(delta)(Ie-4)
C=-I(alpha)(beta)(Ie-8)
The alpha, beta, and delta values are listed in Table 7-3.
Table 7-3
Type
Standard
Alpha
Beta
Delta
Ωat 0℃
PT-100
ITS90
0.003850
0.10863
1.49990
100Ω