Heinrichs Messtechnik
BGN Installation and Operating Instructions
Page 11 of 34
Subject to change without notice
10.1.5.2
With built-in limit switches
When the limit switches are installed, the device becomes an electrical assembly and gets a marking in accordance with
DIN EN 60079 of built-in electrical limit transducers.
The electrical and thermal data and the special conditions of the EU Type Examination Certificate of the built-in limit transducers
must be observed (see also the diagram in Section 10.2.1.
The influence of the fluid temperature on the built-in limit transducers must be observed. The over-temperature of the maximum
fluid temperature based on the maximum ambient temperature must be considered with a factor according to the following table:
Nominal size
Factor for
standard
version
Factor for instruments
with the indicator on
disctance
DN15 and DN25 / 1/2" and 1"
0.2
0.07
DN40 and DN50 / 1,5" and 2"
0.25
0.085
DN80 and DN100 / 3" and 4"
0.3
0.1
DN150 / 6"
Example for built-in limit switch at DN 15 (1/2") and DN 25 (1"):
Max. ambient temperature
T
amb
= 40°C
Max. fluid temperature
T
m
= 120°C
Factor for brought-in heat F = 0.2
Temperature class
T4
T
ü
=
Over-temperature
T
a
=
Ambient temperature of limit switch
C
C
C
Tamb
F
Tü
Ta
C
C
C
Tamb
Tm
Tü
56
40
2
,
0
*
80
*
80
40
120
In accordance with the tables in the PTB 99 ATEX 2219 X EU Type Examination Certificate, the SJ 3,5-... N... inductive sensor must
be operated in the T5 temperature class with an intrinsically safe circuit that does not exceed the maximum values of the Type 3
circuit.
When using the device in hazardous areas, follow the applicable national installation rules.
Example for calculating the max. fluid temperature based on the max. ambient temperature for the built-in sensor Type ES
for DN 15/25.
T
a
= 70°C
T
amb
= 60°C
F = 0.2
C
C
C
C
Tamb
F
Tamb
Ta
Tm
110
60
2
,
0
60
70
10.1.5.2.1 Marking for the device with built in SJ 3,5...N... limit switch
The built-in limit value transmitter from Pepperl & Fuchs is certified for the gas Ex area by the EU type examination certificate PTB
99 ATEX 2219 X and for the dust Ex area by the EU type examination certificate ZELM 03 ATEX 0128 X.
PTB 99 ATEX 2219 X
II 2G EEx ia IIC T6
ZELM 03 ATEX 0128 X
II 1D Ex iaD 20 T108°C
10.1.5.2.2 Marking for the device with built in electric transmitter ES
DMT 00 ATEX 075
II2G Ex ia IIC T6
10.1.5.3
Atmospheric conditions
In accordance with EN 1127, a “potentially explosive atmosphere“ is defined as a mixture of air and combustible gases, vapour, mist
or dust under atmospheric conditions. Such conditions are defined in EN 13463-1, para. 1, with values Tatm = -20 °C to +60 °C and
Patm = 0.8 to 1.1 bar. Outside this range, safety parameters for most ignition sources are not available.
Usually, variable-area flow meters operate under operating conditions outside the atmospheric conditions of 0.8 to 1.1 bar.
Irrespective of the zone classification
–safety parameters of explosion protection – are basically not applicable to the inside of the
measuring tube.