II - DCE FEL ČVUT v Praze

Mechanical Configuration of an Automation System with SIMATIC S7 Ex Modules
Combined use of
Ex and non-Ex I/O
modules
Partition
Load current
circuit
Connecting Ex I/O
modules
1-4
Combined use is possible, however, the minimum thread measure between
conductive parts of Ex and non-Ex assemblies must be maintained in all
cases. As a rule, you must install spacer modules DM 370 between Ex and
non-Ex modules. You must ensure strict separation of intrinsically safe and
non-intrinsically safe conductors in the wiring system. They must be routed
in separate cable ducts. Mixed operation can therefore not be recommended.
The Ex partition must be fitted to achieve the minimum thread measure of
50 mm between Ex and non-Ex modules when using the bus module of the
active backplane bus.
The Ex sensors and Ex actuators are powered either via the Ex modules or
via their own intrinsically safe power supply modules (e.g. 4-wire
transducers).
The Ex I/O modules receive their power supply via the backplane bus. The
24V DC load voltage input of the front connector is required for the power
supply of the Ex sensors and the Ex actuators on the majority of modules.
The Ex I/O modules are configured in the same way as standard modules
from left to right. Connect the Ex sensors and Ex actuators as well as the load
voltage supply with the aid of the line chamber (see Section 1.2) to the
process connector which you then plug into the module.
Note
If necessary, safety assessment of this intrinsically safe power circuit should
be carried out by an expert before a sensor or actuator is connected to an Ex
module.
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04