The H41q System Family
10
3.3.2 I/O Modules
The I/O modules are used for signal transfer and signal matching between the plant and the
central modules. The input and output circuits are always fed into the I/O modules via cable
plugs on the front side. The status of the digital output signals is shown on the LEDs of the
cable plugs. The power supply is either via the cable plugs or via the I/O bus board. The order
of the different I/O module types does not matter.
All I/O modules can be removed or inserted during operation (see chapter 8.1.1).
3.3.3 ATEX (Ex)i-Modules
The current (Ex)i modules exist in 2 construction models:
– non-varnished, with PCB covering
– varnished, with PCB covering
Any models can be equipped together without empty slots between them.
Non-varnished (Ex)i modules may combined together with non-(Ex)i modules without any re-
strictions. There are no free slots necessary on the left or on the right.
With varnished (Ex)i modules with PCB covering the right slot has to remain free in combina-
tion with non-(Ex)i modules, or has to be equipped with a front plate with partition plate
(M 2214). This is also valid for slot no. 15. The slot left to the (Ex)i module may be equipped
with any other module. Spare slots have to be covered by front plates M 2215 (4 spacing units
SU) or M 2217 (8 spacing units SU).
Usable front plates with partition or front plates:
M 2214 Front plate with partition plate 100 x 160 mm
M 2215 Front plate 4 SU
M 2217 Front plate 8 SU
Cable plugs for intrinsically safe circuits are marked and have coded pins, so that they can only
be plugged into the appropriate modules.
3.3.4 Safety-Related Output Modules for SIL 3
All the safety-related output modules meet the requirements of SIL 3.
The safety-related output modules have three semiconductors connected in series. That
means that more than the required second independent component for safety shutdown is now
integrated in the output module.
In case of a fault of an output module the requirements of SIL 3 are valid without time limit. In
the following this feature is called the integrated safety shutdown.
If a safety-related output module should fail during operation then it will be automatically
switched off by the integrated safety shutdown
to get the safe de-energized status.
3.3.5 Special Features of the Output Modules
All output modules have the following special features:
– To increase the availability the outputs of the safety-related output modules can be
switched in parallel without external diodes.
Decoupling diodes are already integrated on the module (see the corresponding data
sheets).
– No output voltage is generated if the supply voltage L- is cut at the output module.
– The connection of inductive loads can be done without using protection diodes at the coil.
However, it is recommended to connect a diode directly at the inductive load avoiding
noise voltages.
– The LED signaling the output status is controlled separately.
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