AS 4852.1 pdf download

AS 4852.1 pdf download.Variable message signs
1.1  Scope
This Standard covers electrically powered, on-road, variable message signs (VMS) used for traffic management and/or driver information applications. Part 1 of this series covers fixed signs, where the display is mounted in a permanent position above or adjacent to the roadway, and Part 2 of this series covers portable signs, where the display is mounted and deployed on a re-locatable trailer. This Standard specifies the requirements for the design, construction, performance and certain aspects of the installation of electrically powered, variable message signs, including their associated control systems. The following types of message signs are not covered in this Standard: (a) Passenger information signs at bus stops, on train stations etc. (b) Variable message signs intended to advertise products and services to road users. (c) Signs that are only capable of displaying either a single message or a blank face.
1.2  Application
Variable message signs conforming to this Standard will be used to provide traffic-related information to motorists, cyclists and pedestrians. This includes road safety messages and real-time traffic information relating to incidents, roadworks and travel times.
1.4  Terms and definitions
For the purpose of this document, the following terms and definitions apply. 1.4.1 alarm class of issue below the severity threshold of a fault Note 1 to entry: Alarms may include minor problems with the sign itself and notifications where the sign is requested to perform an action of which it is not capable (e.g. to display a bitmap larger than the resolution of the sign). Note 2 to entry: Alarms may also include problems with ancillary equipment connected to the VMS for its operation. 1.4.2 border surround or extension to the sign face Note 1 to entry: The border is used to make a message more conspicuous by isolating it from its background and to reduce the effects of glare when the sun is low and behind the sign. 1.4.3 character height height of an upper-case character Note 1 to entry: For additional information on character dimensions, see Figure 5.2. 1.4.4 character matrix matrix of pixels required to display the character Note 1 to entry: This applies to any given font. 1.4.5 character spacing horizontal distance between the closest characters in the same word or numeral set 1.4.6 display face of a sign used to form the message 1.4.7 equivalent area apparent visual area of the lit pixel Note 1 to entry: The width of the equivalent area is taken to be numerically equal to the centre-to-centre distance of any two adjacent pixels, see Figure 5.2.1.4.8 error code attribute of a protocol that may contain one or more class of issues (e.g. fault, alarms and events) 1.4.9 event activity that is logged by the VMS Note 1 to entry: Events have the lowest severity status and are used as an audit trail of actions performed by the VMS. 1.4.10 fault class of issue that materially prevents the VMS from performing its functions Note 1 to entry: For a fault the root cause is the VMS itself, which may be either a hardware or software fault or both. 1.4.11 frame stable state displayed on a VMS that is preceded by and followed by a change of state Note 1 to entry: It will typically consist of text, symbols, a combination of the two, or a blank display. 1.4.12 line spacing vertical distance between lines of characters Note 1 to entry: Line spacing is expressed in terms of the number of inactive pixels.1.4.17 pixel smallest switched unit from which active messages are created Note 1 to entry: This applies to any given font on any given sign. 1.4.18 plan defined combination of messages, complete with relative timing 1.4.19 product host control system PHCS software program supplied by the sign manufacturer for remote and local control, configuration, monitoring, testing and diagnostics of the sign 1.4.20 shall indicates that a statement is mandatory 1.4.21 should indicates a recommendation