EN 12675-2017 pdf download.Traffic signal controllers – Functional safety requirements.
4.2 Application of power
On application of power to the traffic signal controller, the controller shall undertake internal checks to ensure that the operating programs start in a pre-defined condition. In the event the predefined conditions could not be achieved, the traffic signal controller shall not change to the normal mode of operation.
4.3 Diagnostic checks of traffic signal controller logic system
Continuous diagnostic checks shall check the traffic signal controller logic system. In the event of an error, the traffic signal controller shall change to the failure mode.
4.4 Classification of faults
This European Standard defines the minimum specification for a traffic signal controller with respect to safety for the road user. This safety consists of avoiding the display of incorrect messages on signals that are liable to endanger road users (e.g. conflicting signals, missing or unwanted signals, wrong timing). The controller shall be capable of taking action as required by the selected class and taking into account the following:
a) Where a class includes a 0 there is no requirement to provide checks. Therefore, this European Standard does not specify the requirement to provide the function, the monitoring for the fault condition or the action to be taken if the function is provided.
b) For specified major and minor faults the traffic signal controller shall record the faulty signal group outputs, record the affected signals, and record the fault as specified in 5.4.
c) For a traffic signal controller to comply with this European Standard, from each following paragraphs 1) and 2), at least one combination of classes shall be declared:
1) For a traffic signal controller to comply with this European Standard, at least one of the classes Ml, AE1 as specified in 4.5.1 shall be declared orAFi as specified in 4.5.2 shall be declared.
2) For a traffic signal controller to comply with this European Standard, class DAI as specified in
4.8 shall be declared, or at least one of the classes CAl, CBI, Ccl, or CDI as specified in 4.7.1, and class CE1 as specified in 4.7.2, shall be declared.
d) The time interval for the traffic signal controller to detect the occurrence of a fault and change to a safe state shall be in accordance with EN 50556:20 11, 5.2.3.3.
e) The fault value of luminous intensity for an absent signal, signal 0N” requirement of signal intensity for safety, shall be as specified in EN 50556:2011, 5.2.2.
Class AM: The occurrence of any signal group green signals displayed simultaneously with any conflicting signal group green signals shall register a fault.
b) Green – yellow conflict
Class ABO: There is no requirement to check for conflicting green and yellow signals.
Class AB1: The occurrence of any signal group green signals displayed simultaneously with any conflicting signal group yellow signals shall register a fault.
cJ Yellow – yellow conflict
Class ACO: There is no requirement to check for conflicting yellow signals.
Class ACI: The occurrence of any signal group yellow signals displayed simultaneously with any conflicting signal group yellow signals shall register a fault.
d) Green – red/yellow conflict
Class ADO: There is no requirement to check for conflicting green and red/yellow signals.
Class AD1: The occurrence of any signal group green signals displayed simultaneously with any conflicting signal group red/yellow signals shall register a fault.
e) Green – green/yellow conflict
Class AEO: There is no requirement to check for conflicting green and green/yellow signals.
Class AE1: The occurrence of any signal group green signals displayed simultaneously with any conflicting signal group green/yellow signals shall register a fault.
4.5.2 Signal group green/absent red conflict
In the event that configured signal group red signals are not displayed with a signal group green signal, it shall have an effect according to one or more of the following classes.
a) Absence of any conflicting red signal
Class AFO: There is no requirement to check for any absent signal red.
Class AF1: The absence of any red signal with a conflicting green or conflicting yellow signal, shall register a fault.EN 12675-2017 pdf download.
EN 12675-2017 pdf download
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