vs | plus

How the detector status is defined in the event of a fault is configured on the control unit. vs | plus has no influence on this. vs | plus assumes that a detector reports a permanent occupancy in the event of a fault. In the fault parameters, there is a simple way for vs | plus to recognise a detector fault itself. The "maximum occupancy duration" parameter can be used for this purpose. This option is only intended for testing with simulation tools and should not be used in normal operation.

The detectors of a traffic stream can be parametrised with replacement detectors for the extension in the event of a fault. A separate time gap for the extension must also be specified for this replacement detector. Alternatively, there are further entries for the "Replacement detector" parameter: These are described in the following sections. As of vs | plus version 8.0.1, the options for this parameter have been extended.

The following attributes can be set for each vs | plus detector:

• Maximum occupancy time: In test or simulation scenarios, exceeding an occupancy time can be recognised as a fault, e.g. if the control unit is unable to send a fault message. Once the maximum occupancy time has been reached, the detector is recognised as faulty.
• Backup detector GP: The replacement detector of the faulty detector determines the extension of the assigned traffic stream. If several detectors are assigned to a traffic stream, their replacement detectors also influence the extension of the traffic stream. In addition to real replacement detectors, other options can also be specified. Further information on this is available in the "Replacement detector" chapter.
• Gap for backup detector: This entry is only necessary if a real replacement detector is used for the extension. In this case, only the replacement time gap is relevant. The occupancy rate is not taken into account.

Standard behaviour

In principle, a traffic stream can extend up to the parametrised maximum green 2 (tg max2) if none of its detectors are faulty. The default behaviour if all detectors of a traffic stream are faulty is programmed so that the traffic stream is registered with a fault message. The default behaviour occurs if there is no parametrisation for detector faults or "Permanent extension" is entered as a replacement detector. The traffic stream receives its minimum green 1 (tg min1) per release if no maximum green for detector fault (tg_maxFail) is parametrised (for the traffic stream parameter times, tg_maxFail is 0). The values for maximum green 2 (tg max2) and maximum green for detector fault influence the maximum length of time a traffic stream can extend in the event of a fault. If a duration is entered for the maximum green in the event of a detector fault, the traffic stream can extend to the shorter duration compared to the maximum green 2 (see also the following table).

Replacement detector

• If a replacement detector is assigned to the detector, it takes over the task of recording information for the extension of the controlled traffic stream in the event of a fault. In this case, a replacement time gap must be specified, which determines the extension via the replacement detector.
• If the reference to the own identification is entered as a replacement detector, the traffic stream receives its parameterised minimum green 1, unless the other detectors of the traffic stream are not faulty or are parameterised with replacement detector "Permanent extension". It can then extend to the lower value between maximum green 2 or in the event of a fault (see following table).

• If continuous extension is specified as the replacement detector, the standard behaviour is used in the event of a fault (see table Standard behaviour).
• If fault handling is inactive, the normal parameterisation applies, as the detector is always considered to be not faulty. This means that the traffic stream is allowed to extend to the maximum green 2. Exception: In the event that all other detectors in the traffic stream are also faulty and at least one of the backup detectors is configured with "continuous extension", the standard behaviour applies (see following table).

Extension of the replacement detector function from vs | plus version 8.0.1

The "Deactivate detector" entry for the replacement detector causes the following behaviour in the event of a fault: 

• As long as functional detectors exist for a traffic stream, the traffic stream can neither register nor extend over the fault of the deactivated detectors.
• The standard behaviour (see above) is triggered in the event of requests from the non-jammed detectors or a fault in all detectors of the traffic stream. If all detectors are faulty and parameterised as "deactivated", the traffic stream receives a fault message and its minimum green 1 per release (see following table).

The "Detector inactive" entry for the replacement detector causes the following behaviour in the event of a fault: 

• As long as functional detectors exist for a traffic stream, the traffic stream receives neither a fault notification nor an extension due to the malfunction of the "inactive" detectors. 
• If all detectors of the traffic stream are faulty and parameterised with "Detector inactive", the traffic stream can neither register nor extend.
• In the other cases, the standard behaviour applies (see table below).