For internal use only
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Siemens
KNX bus communications
CE1P3127en
Building Technologies
Large plants
2013-04-08
8.2.5
System time, alarms, and remote time adjustment
The system time (time and date) is communicated in S-Mode and not affected by
LTE filtering.
Alarms and remote time adjustments are transmitted in LTE-Mode (LTE broadcast
address). This address is listed in the predefined LTE filter table and therefore
subject to LTE filtering.
N146
N140/13
S
y
s
te
m
t
im
e
(
ti
m
e
a
n
d
d
a
te
)
S
-m
o
d
e
LTE filter table
N
o
rm
a
l
(r
o
u
te
)
R
o
u
te
a
ll
B
lo
c
k
a
ll
A
la
rm
s
,
re
m
o
te
t
im
e
a
d
ju
s
tm
e
n
ts
,
L
T
E
-m
o
d
e
(e.g. Main line 1)
Primary line
Sekundary line
(e.g. Line 1)
3
1
2
7
Z
2
0
e
n
The diagram shows the following:
The system time (time and date) is always transmitted by devices on the primary
line to devices on the secondary line and vice versa
two-way communication.
If the filter is set to "Normal (route)" in the area/line couplers and IP routers, alarms
and remote time adjustments are transmitted only from the secondary line to the
primary line
one-way communication.
If "Route all" is set, alarms and remote time adjustments are transmitted from the
secondary line to the primary line and vice versa
two-way communication.
"Block all" means that the transmission of alarms and remote time adjustments is
blocked
no LTE telegram communications.
In a network with couplers and IP routers, only one RM… controller can function as
time master (see Section 6.1.2).
The time can only be adjusted remotely via a time slave if the time master is
located on the same line or on the next higher line.
System time
Alarms and remote time
adjustment
Two-way and one-way
communication
Normal (route)
Route all
Block all
Time synchronization