Plus+ ST950 Traffic Signal Controller

Product Details:

ST950 standard intersection traffic controllers support all appendices A – L in TOPAS 2500B.  However, when ‘stand-alone pedestrian stream’ (rather than intersection) is selected in the IC4 configuration, only the following appendices are applicable –

Appendix C – Cableless Linking

Appendix J – Pedestrian Facilities

Appendix K – user interface

Appendix L – speed measurement

Exceptions/exclusions:

3.5        On Plus+ ST950 Controllers, the start-up time is dependent on the number of Nodes. The start-up time can be longer than 120 seconds but is typically under 3 minutes (180 seconds). This is not considered to be a critical issue and is intended to be made compliant in future releases

3.22      The ST950 controller series only logs events that we believe are important in helping diagnose problems, and thus most ‘internal’ events from the OS that do not affect operation are not normally logged.

D13       The Plus+ ST950 Controller is also required to extinguish the stream when the Nodes controlling the red signals are ‘unavailable’ due to temporarily power or communications issues for example, but also to resume normal operation automatically when communications is restored without needing to be manually reset. The distributed architecture of the Plus+ Controller allows it to confirm the operation of each individual signal Node, allowing safe automatic restoration of facilities when the fault condition is no longer present

I16        For consistency, the ST950 controllers will always start timing the ‘inhibit period’ (if conditions require it to run) when the priority phase gains right of way and not when the previous phases are terminated

The option for the Works Specification to request manual clearance has been withdrawn because it would require manual intervention to reset faults triggered by a temporary loss of power or communications to one or more Nodes. The distributed architecture of the Plus+ Controller allows it to confirm the operation of each individual signal Node and red optic, allowing safe automatic restoration of facilities when the fault condition is no longer present.

Where the actions were taken due to loss of communications with the signal Nodes due to power failures for example, the Plus+ Controller resumes normal operation automatically when communications are restored. The distributed architecture of the Plus+ Controller allows it to confirm the operation of each individual signal Node, allowing safe automatic restoration of facilities when the fault condition is no longer present.

K2D – Crystal The accuracy of the built-in Crystal Clock does not meet this tolerance over the complete temperature range.

However: Tolerance Category D is only called up by CLF parameters. For long term synchronisation of CLF Plans, the permitted tolerance of one second every day is not adequate and therefore we do not recommend the use of a local Crystal Clock. We would recommend the use of the Mains Frequency Synchronised clock, and this is the default operation of our controllers.  In addition, the controller can also use an external timing source, e.g. GPS Clock or NTP Server, which would be used to maintain the accuracy of the crystal synchronised clock.