Delta Controls DPT-2000 - Manual (Page 5)

3 IOM-DPT-A: FEB 2014
primary a nd secondary windings in which don’t appear voltage higher than 250V. The duty of power
supply installation with above mentioned requirements rests on user.
Appendix Exd.01
5.3. Measurements of operating temperature of transmitter
5.3.1. After installing the DPT-2000ALW transmitter for the medium maximum expected temperature and
expected the maximum ambient temperature measure out Tp temperature of the most hot place on the
surface of transmitter and determine the temperature transmitter class or a maximum surface
temperature according to p. 5.4.
When measuring the warmed media, above ambient, is recommended to determine the temperature of the
stub while is screwed into the transmitter or at the wall of the pipe or tank as shown below.
5.3.2. When medium is heated above ambient temperature it is allowed to determine the temperature class
of the transmitter or the maximum surface temperature Tp through the adoption of a maximum
temperature of the medium which provides the technological process. Measurement
of Tp isn’t then
necessary.
If during the measurement of Tp for maximum temperature expected for the medium is not possible to
ensure the maximum expected ambient temperature after the measurement of Tp
one can estimate the potential growth in temperature Tp due to the increase of ambient temperature.
5.3.3. If the other elements of the plant have or may have a temperature higher than the highest temperature Tp
on the transmitter, security conditions must be ensured in accordance with accepted principles in such cases
Temperature transmitter
Tp
Thermal shield
Safe area
Safe area
Zone 0
Zone 0
Temperature transmitter
measuring insert
Shield of the
Zone 1 or 2
Tap
Thermal shield
Tp
Zone 1 or 2
Shield of the
measuring insert
Tap
Thermal isolation
Thermal isolation
5.4. Determination of the transmitter temperature class T * for gas and the maximum surface temperature
1. Determine the temperature class of the transmitter for the gas or the maximum temperature for
combustible dust depending on the temperature Tp from the formula:
T*  Tp+0,1Tp+5K for class T3..T6
T*

Tp+0,1Tp+10K for class T1, T2
2. Determine the maximum surface temperature transmitter for combustible dust from the formula:
T*

Tp+0,1Tp
3. The following table contains the values of permissible ambient temperature depending on the
temperature Tp and temperature class of the transmitter.
Tp[

C] Temperature class and ambient temperature Ta[

C]
Tp  75  C
T6 and Ta=45

C
T5 and Ta=75  C
Tp>75  C
T4 and T5 Ta=70

C
T3 and T2 Ta=65  C
T1 Ta=60

C
Tp- transmitter temperature measured in clause 5.3
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