Siemens ET 200S Manual page 547

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 a single
ground-fault detector:
+
R
ET 200S
R
ET 200S
R
Module
N
+ R
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.
Distributed I/O System ET 200S
EWA 4NEB 780 6024-02 07
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 + 9, 5 MW
PM*E DC24V Modul
Leakage resistance of the IM151-1 interface module
Leakage resistance of the PM-E 24 VDC power module
Formula for Determining the Leakage Resistance of an ET 200S Station
Ohmic Resistance from RC Network
10 MΩ (−5%)
10 MΩ (−5%)
–––
E
E-1