Aplisens SGE-25S Manual del usuario - Página 5
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C
6. Supply examples.
Power supply with a "linear" characteristic may be e.g. a typical barrier with parameters:
Uo=28V Io=0.093A Rw=300
Rw
Ui
Fig.1. Power supply from a source with linear characteristic"
Example of power supply from a source with trapezoidal characteristic (see Fig.2).
Uo=24V Io=0,1A
If Uo < ½ Uq then
For power supply with rectangular characteristic:
Supplementary attentions:
The supply of power from a source with a rectangular characteristic means that the voltage of the
Ex power supply remains constant until current limitation activates.
The protection level of power supplies with a "rectangular" characteristic is normally "ib".
The probe powered from such a supply is also a Ex device with protection level "ib".
Example of practical provision of power supply with a rectangular characteristic:
use a stabilized power supply with Uo=24V with protection level „ib" and current limited to 25mA < Io < 30mA
6.1. The protection level
The probe is Ex device with protection level „ia" when the powered circuit have protection level „ia".
The probe is Ex device with protection level „ib" when the powered circuit have protection level „ib".
PROBE
Fig.3. SGE–25.SMART, SGE–25S.SMART, SGE–25C.SMART probes in Ex version – connection method
Devices in the measurement loop of the probe should be connected in accordance with
Intrinsic safety and explosion protection standards.
It is not permitted to repair or otherwise interfere with the probe's electrical circuits in any way.
Damage and possible repair may be assessed only by the manufacturer or another authorized
party.
Appendix Ex.03 (SGE–25.SMART, SGE–25S.SMART, SGE–25C.SMART)
Ω
.
Rw
ID
Uo
Ii
Ui
Fig. 2. Power supply from a source with trapezial characteristic
4Po
Uq =
,
Rw =
Ii
Hazardous area
Red
+
_
Black
Probe cable
3
I
D
Example of practical provision of power supply for case:
use the barrier with the parameters given above
Io
Rw
Uo
Uq
,
Po =
Io
Terminal box
F1
F2
PF
RE
ABC
DEF
7
8
JKL
M NO
4
5
STU
VWX
1
2
I
D
Uq
Uo(Uq-Uo)
Rw`
Safe area
+
≥250Ω
R
_
Communicator certified for connection
to a signal line leading to a danger zone.
In the absence of such a certificate,
F3
F4
PV
F4
GHI
@%&
9
0
the transmitter should be configured
PQR
+/
*
6
YZ#
.
3
and calibrated within a safe zone.
DTR.SG...04
(ENG)
a Ex power supply
see p.5 and 6.