Siemens SIMATIC ET 200S Manual page 575

Determining the Leakage Resistance of an
ET 200S Station
Ohmic resistance
When determining the leakage resistance for an ET 200S station (for a
ground-fault detector, for example), you must take into account the ohmic
resistance from the RC combination of each module:
Interface module
PM-E 24 VDC power module
PM-E 24 VDC / 120/230 VAC power module
Formula
You can use the following formula to calculate the leakage resistance of an ET
200S station if you secure all the modules listed above with one ground-fault
detector:
R
ET 200S
R
ET 200S
R
module
N
R
IM 151
R
IM 151
R
PM-E 24 VDC
Figure E-1
If you secure the modules listed above in an ET 200S station with a number of
ground-fault detectors, you must obtain the leakage resistance for each
ground-fault detector.
ET 200S Distributed I/O System
EWA-4NEB 780602402-12
Module
R
Modul
=
N
Leakage resistance of the ET 200S station
Leakage resistance of a module
Number of power/interface modules in the ET 200S station
= R = R
PM−E DC24V Modul
Leakage resistance of the IM1511 interface module
Leakage resistance of the PM-E 24 VDC power module
Formula for calculating the leakage resistance of an ET 200S station
Ohmic resistance from RC network
= 9.5 MΩ
E
10 MΩ (−5%)
10 MΩ (−5%)
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E-1