Rheonics | Switzerland | U.S.A.
SRV, SRD, SRV-FPC, SRD-FPC Installation and Intrinsic Safety Manual
P. 10
Version 2.0, Updated: October 29, 2020
Rheonics GmbH, Klosterstrasse 19, 8406 Winterthur, Switzerland
©Rheonics. Rheonics confidential and proprietary information.
3.2.2.
Electrical parameters relevant to intrinsic safety
Table 1: EX-relevant electrical specification for SRV/SRD sensors
Parameter
RTD (Pt1000) circuit
Transducer coil circuit
U
i
9V
7.3V
I
i
5 mA
730mA
P
i
41 mW
1.3W
C
i
negligible
negligible
L
i
negligible
<44µH
The two circuits are considered independent because they are electrically isolated from one
another.
3.2.3.
Temperature rating of the sensors according to T class
The following temperature class table shows the range of ignition temperature classes for which
the sensors are specified, together with the ambient operational temperature for each class,
where Ta is the lesser of the process fluid temperature and the ambient temperature
surrounding the portion of the sensor outside of the process fluid. In typical applications, the
fluid temperature will be equal to or greater than the ambient temperature, so it will determine
the temperature class.
The symbol “Tx” refe
rs to the corresponding symbol on the sensor EX
label. It refers to the temperature classes listed on the following Table 2. However, the user
must be aware that these temperatures only show the limits for safe operation of the sensor in
different explosive atmospheres. The actual temperature range over which the sensor will
function accurately and without functional damage is shown on the individual configuration data
sheet provided with each sensor.
Table 2: Temperatures for gas ignition classes
Tx
(T class)
Ta
T6
-
40°C….+70°C
T5
-
40°C….+85°C
T4
-
40°C….+120°C
T3
-
40°C….+1
85°C
