Siemens SIMATIC ET 200SP HA, System Manual

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Leakage resistance of the IO device
C
Introduction
If you want to protect the IO device with ground fault monitoring or an FI switch, you need the
leakage resistance to select the correct safety component.
Ohmic resistance
You must consider the ohmic resistance from the RC combination of the respective module
when determining the leakage resistance of the IO device:
Table C-1 Ohmic resistance
Module Ohmic resistance from RC network
Interface module 10 MΩ
Terminal block TB...D
for feeding the supply voltage
10 MΩ
Formula
If you protect all of the above modules with ground fault monitoring, you can calculate the
leakage resistance of the IO device using the following formula:
R
ET200SPHA
= R
module
/ N
R
ET200SPHA
= Leakage resistance of the ET 200SP HA
R
module
= Leakage resistance of a module (see "Ohmic resistance" table)
N = Number of modules in the ET 200SP HA (interface modules and TB...D
terminal block only)
If you protect the modules listed above within an IO device with several ground fault monitors,
you must determine the leakage resistance for every single ground fault monitor.
Example
The following components are in an IO device:
● An interface module
● Two TB...D terminal blocks
● Various I/O modules
The complete IO device is secured with one ground fault monitor:
5
(763+$
0വ
0വ
ET 200SP HA Distributed I/O system
System Manual, 08/2019, A5E39261167-AD
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