Fail-Safe Modules
7.7 4 F-DO DC24V/2A PROFIsafe digital electronic module
ET 200S Distributed I/O System - Fail-Safe Modules
164
Installation and Operating Manual, 08/2008, A5E00103686-07
Switching Grounded Loads
If the EM 4 F-DO DC24V/2A PROFIsafe switches loads that have a chassis-ground
connection (for example to improve EMC characteristics) and if chassis and ground are
connected at the power supply being used, a "short circuit" is detected.
From the perspective of the F-module, the M-switch is bridged by the chassis-ground
connection (refer to the diagram below as an example of an EM 4 F-DO DC24V/2A
PROFIsafe).
Remedy:
●
Using the PM-E F pp DC24V PROFIsafe
●
The value of the resistance between chassis and ground at the load end must be greater
than 100 kΩ
3
3
0
0
(0)'2'&9$352),VDIH
0
3VZLWFK
5HDGEDFNRIFXUUHQWVRXUFHRXWSXW
&HQWUDO
JURXQGLQJ
SRLQW
0VZLWFK
/RDG
5HDGEDFN0RXWSXW
Figure 7-47 Switching Grounded Loads (with resistance between chassis and ground)
Capacitive Crosstalk of Digital Input/Output Signals
Refer to
"Properties of the power module PM-E F pm DC24V PROFIsafe".