7 Guidelines for station planning
7.2 Maximum station extension
XI/ON: XNE-GWBR-2ETH-MB
10/2011 MN05002008Z-EN
www.eaton.com
139
7.2
Maximum station extension
The maximum number of modules within XI/ON station with the gateway XNE-GWBR-2ETH-
MB depends on the following factors:
• The station extension may not exceed the maximum number of
32 modules
.
• The maximum permissible number of
192
communication bytes which are transmitted via
the module bus from the modules to the gateway must not be exceeded (see below Table
74: Communication bytes and nominal current consumptions of the XI/ON modules from
the modul bus IMB, Page 139).
• If the maximum sum of the modules’ nominal current consumptions (see below Table 74:
Communication bytes and nominal current consumptions of the XI/ON modules from the
modul bus IMB, Page 139) right to the gateway (max. sum
Σ
I
MB
=
400 mA
) is reached, a
bus refreshing module has to be used in order to provide the module bus voltage.
To the right of the bus refreshing module, the sum of the modules’ current consumptions
can amount to
1.5 A
.
For the calculation of the maximum system extension, the following table contains an over-
view about communication bytes as well as about the modules’ nominal current consump-
tions
:
Attention
Ensure that a sufficient number of bus refreshing and power feeding modules are
used if the system is extended to its maximum.
Note
If the system limits are exceeded, the software I/O-ASSISTANT generates an error
message when the user activates the menu item [Station] > [Verify].
Table 74:
Communication
bytes and
nominal current
consumptions
of the XI/ON
modules from
the modul bus
I
MB
Module
Number of
communication bytes
Nominal current
consumption from
module bus I
MB
XN-BR-24VDC-D
2
–
XN-PF-24VDC-D
2
≦
28 mA
XN-PF-120/230VAC-D
2
≦
25 mA
XN-2DI-24VDC-P
1
≦
28 mA
XN-2DI-24VDC-N
1
≦
28 mA
XN-2DI-120/230VAC
1
≦
28 mA
XN-4DI-24VDC-P
1
≦
29 mA
XN-4DI-24VDC-N
1
≦
28 mA
