Rosemount 396R, Instruction Manual

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Instruction Manual Maintenance
LIQ-MAN-396R-396RVP March 2017
Maintenance 47
6.5 Automatic Temperature Compensator
The temperature compensator element is temperature sensitive and can be checked with an
ohmmeter. Resistance increases with temperature.
The 3K element will read 3000 ohms ±1% at 25°C (77°F) and a Pt-100 will read 110 ohms. Resistance
varies with temperature for a 3K and Pt-100 element and can be determined according to
Table 6-2 or the following formula:
R
T
=R
0
[l+R
1
(T-20)]
Where R
T
= Resistance
T = Temperature in °C
Refer to Table 4-1 for R
0
and R
1
values
Table 6-1: R
0
and R
1
Values for Temperature Compensation Elements
Temperature Element R
0
R
1
3K 2934 0.0045
PT-100 107.7 0.00385
Table 6-2: Temperature vs Resistance of Automatic Temperature Compensator Elements
Temperature °C Resistance (Ohms) ±1%
3K PT-100
0 2670 100.0
10 2802 103.8
20 2934 107.7
25 3000 109.6
30 3066 111.5
40 3198 115.4
50 3330 119.2
60 3462 123.1
70 3594 126.9
80 3726 130.8
90 3858 134.6
100 3990 138.5