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Uniform system time
Autonomous (value 0)
Slave without remote
readjustment (value 1)
System time master
(value 2)
Error / diagnostic
messages from the LMU...
86/171
Siemens Building Technologies
HVAC Products
5.1.4 System functions
In addition to the aforementioned applications, the interconnected system with
ALBATROS controllers offers a number of other system-specific functions.
Through appropriate configuration of each system user, a central clock time source can
be selected from the interconnected system of units, which is then used for
synchronization by the other units.
Special ALBATROS components, such as the AUF77 radio clock, deliver very accurate
time information and can be straightforwardly integrated into an LPB system.
Clock time handling on the LPB can be defined on the LMU... with parameter
«LPBKonfig0» and bitfield «ZeitSynchro».
The following settings can be made:
The clock time of the LMU... will not be synchronized with the system time on the LPB.
This is the standard setting.
The clock time of the LMU... will be synchronized with the system time, which means
that a clock time available on the LPB will be adopted.
Remote readjustment of the system time by an operating unit of the LMU... is not
possible with this setting, nor is it possible otherwise!
The clock time of the LMU... will be made available on the LPB as the system time and
can be used by the other ALBATROS devices.
Remote readjustment via other RVA... controllers is not possible with this setting either.
When making the clock time configuration on the LMU..., the following rules must be
observed:
Ø Use of the system time by the LMU... makes sense only if it can be displayed by a
RU (QAA73...) or an operating unit (AGU2.310...)
For that purpose, on the QAA73. .., parameter «Uhrzeitmaster» on line 96 must be
set to 1 = BMU.
The AGU2.310... will adopt the clock time automatically.
Operation of a QAA53... is not possible with this setting since this unit cannot handle
clock time information.
Ø If no clock time source is connected to the LMU... (QAA73..., QAA53... or
AGU2.310...), it cannot deliver any valid clock time to the system. In that case, an
error message («Ungültige Uhrzeit» = 95) will be delivered
Ø Configuration of 2 units from the system as clock time master is not permitted and
generates error message «Zwei Uhrzeitmaster» = 100.
If there are several clock time sources in the system, the source to be selected for the
system time should be the one that delivers complete time and date information.
Excluded from this rule are interconnected systems using the QAA53... because that RU
cannot make use of the clock time.
Error and diagnostic messages from the LMU... are delivered via the LPB and appear
on the display of the RVA... controllers.
Each message consits of an error code, which is clearly defined throughout the system,
and a priority, which is used to select the highest priority should several errors occur at
the same time.
In connection with the communication interface OCI6... and high-priority error
messages, alarms can be sent to remote operating stations, ensuring remote
supervision of heating plant.
Basic Documentation LMU54... / LMU64...
5 Clip-in module OCI420... for communication via LPB
CC1P7494en
07.11.2002
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