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44.4
Last Lamp Failed Monitoring
44.4.1 Introduction
With Last Lamp Failed Monitoring, faults are only reported when the current monitored
by a sensor falls below a configurable threshold. This threshold is typically set so the
fault is triggered when the last lamp fails, hence its name.
This differs from Red Lamp Monitoring in that no actions are taken before this point,
e.g. Red Lamp Monitoring would react when two out the three signals failed.
Last Lamp Failed Monitoring also differs from Red Lamp Monitoring in that it can be
configured to monitor outputs of any colour, not just reds.
44.4.2 Faults Actions
When the current is confirmed below the threshold, a standard lamp fault report is
generated. For example, a 30W lamp fault reported and the learnt load is reduced to
zero if the load learnt was 30W before the last lamp fault was confirmed.
The System Log, Fault Table, LMU Readings and Last Lamp Status web pages and
LLE/LLF handset commands identify the fault as a last lamp fault.
Typically further Fault Actions are required and there are two choices:
Software Fail Flashing – If the Fail to Part-Time facility is enabled (section 42),
the associated stream enters its configured part-time state, usually flashing
ambers.
Hardware Fail Flashing or ‘All Off’ – If the Fail to Part-Time facility is not
enabled, the controller is shutdown.
In both cases, the Second Red / Last Lamp Fault FLF22 is also reported to indicate
that actions have been taken, with the fault data identifying the phase(s).
This fault can only be cleared manually either locally or remotely* using the normal fault
log reset features. The lamp fault report will be cleared when the Lamp Monitor learns
the replaced lamp load (unless the ‘Last Lamp Faults Only’ option is enabled – section
44.4.7).
In addition, Special Conditioning can read the state of the last lamp faults and trigger
actions.
44.4.3 Configuration
The Last Lamp Failed Monitoring facility must be enabled using the IC4 Configurator.
However, once enabled, all the settings can be modified using web pages and handset
commands.
Note: Last Lamp Monitoring and Red Lamp Monitoring are mutually exclusive; both
facilities cannot be enabled in the same configuration.
* If the controller is shutdown, the fault reset requires the Remote Reboot feature (section 7).
Security classification
Unrestricted
Version
4
Last Editor
Paul Cox
Document Name
ST950 Facilities Handbook
Copyright © Siemens plc 2015. All Rights Reserved.
Page
261 of 303
Status
Issued
Date
16-Jul-2015
Document No.
667/HB/46000/001
Mobility is a division of Siemens Plc