Ranges Of Application Of Power Supplies - Pepperl+Fuchs KLD2-PR-Ex1.IEC. Manual

Power repeater / power supply according to IEC 61158-2
Each field device causes a voltage drop on the length segment through which its pow-
er supply current flows. For the first station, this would be:
U = i
RL1
For the second station, this appears as follows:
In general, the equation for Ex applications is then as follows:
If the condition described above is not fulfilled,
a) the lead has be shortened or
b) a lead with reduced resistance coating has to be used.
When selecting the lead type, make certain that for Ex applications, the
requirements in terms of insulation voltage and single wire insulation of
EN 60079-14 Section 12 and characteristic values are observed
according to the FISCO model or the Entity model.
Please note that the length to be specified represents the length of the
line between the terminals of the power repeater and the respective sta-
tion.
If the opposite approach is selected, in other words if you would like to determine
whether the input voltage U
station, the following equation must be used as the basis:
5.2

Ranges of application of power supplies

The power supplies are provided to feed non-intrinsically safe H1 field bus segments
or field bus segments with ignition protection type "Non-incendive". The following il-
lustration shows an example.
Subject to reasonable modifications due to technical advances.
16
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*R or U = i * l
1 L1 RL1 1 1
U = i * (R
RL2 2 L1
U = R' *
RL
for a specified application is sufficiently high on the last
on
U = U - U = U
in out RL
FOUNDATION FieldbusGeneral
* R'; with R' = resistor coating of the lead
+ R ) or U = i * l
L2 RL2 2
n
Σ
!
(i * l ) < U - 9 V
x x out
x=1
n
Σ
- R' * (i * l ) > 9 V
out x x
x=1
* R'
2
!
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