Plugging In An Ex I/O Module Or Bu Cover - Siemens SIMATIC ET 200SP HA System Manual

5.2.4

Plugging in an Ex I/O module or BU cover

Connecting Ex I/O modules
The Ex I/O modules are assembled like standard I/O modules from left to right. The Ex sensors
and Ex actuators are connected directly to the Ex BaseUnit.
Note
Before sensors or actuators are connected to an Ex I/O module, an expert must perform a safety
analysis of the intrinsically safe circuit, if necessary.
Coding element
Ex I/O modules have a mechanical, two-part coding element.
• The coding element is located on the Ex I/O module at the factory.
• The first time an Ex I/O module is plugged in, a part latches into the Ex BaseUnit. The second
part of the coding element also remains on the Ex I/O module when the Ex I/O module is
removed.
• The part of the coding element that is latched onto the Ex BaseUnit encodes this slot to the
type of the Ex I/O module.
• Acting as a mechanical lock, the coding element prevents incompatible Ex I/O modules from
being connected to the Ex BaseUnit. Another type of Ex I/O module can only be plugged in
after the coding element of the part latched in the Ex BaseUnit has been removed.
BU cover (slot covers)
The BU covers are plugged in when no Ex I/O module is inserted in the respective slot.
The BU covers have a holder for a reference identification label on the inside. If the I/O station is
removed in the future, remove the equipment labeling plate from the holder and plug it onto the
final Ex I/O module.
Modules for devices in a hazardous area
System Manual, 04/2021, A5E50165138-AA
5.2 Mounting the Ex module group
Installation
57