OBIX

Key takeaways

OBIX belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect OBIX to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of OBIX from memory before moving on to harder problems.

Reference excerpt

oBIX (for Open Building Information Exchange) is a standard for RESTful Web Services-based interfaces to building control systems. oBIX is about reading and writing data over a network of devices using XML and URIs, within a framework specifically designed for building automation. Building control systems include those electrical and mechanical systems that operate inside a building, including Heating and Cooling (HVAC), Security, Power Management, and Life/Safety Alarms that are in nearly all buildings as well as the myriad of special purpose systems that may be tied to particular buildings such as A/V Event Management, Theatre Lighting, Medical Gas Distribution, Fume Hoods, and many others. oBIX is a web services interface because it does not necessarily allow deep interactions with the underlying control systems. This interface can enable communications between enterprise applications and embedded building systems as well as between two embedded building systems. Facilities and their operations to be managed as full participants in knowledge-based businesses. oBIX is being developed within OASIS[1], the Organization for the Advancement of Structured Information Standards. Version 1.0 was completed as a committee standard in December 2006.

Background Presently most mechanical and electrical systems are provided with embedded digital controls (DDC). Most of these devices are low cost and not enabled for TCP/IP. They are installed with dedicated communications wiring. Larger DDC controllers provide network communications for these dedicated controllers. There are many well established binary protocols (BACnet, LonTalk, Modbus, DALI) that are used on these dedicated networks in addition to numerous proprietary protocols. While these binary protocols can be used over TCP/IP networks - they have challenges with routers, firewalls, security, and compatibility with other network applications. There is an added challenge in that the industry is split between several largely incompatible protocols. Because oBIX integrates with the enterprise, it enables mechanical and electrical control systems to provide continuous visibility of operational status and performance. By exposing these operations using web services, it enables owners and tenants to use the full array of standard databases and OLAP tools to analyse their performance. oBIX enables facilities operators, owners and tenants to make decisions based on a fully integrated consideration of all life-cycle, environmental, cost, and performance factors.

Scope oBIX provides a publicly available web services interface specification that can be used to obtain data in a simple and secure manner from HVAC, access control, utilities, and other building automation systems, and to provide data exchange between facility systems and enterprise applications. Release 1 provides a normalized representation for three of elements common to control systems:

Points: representing a single scalar value and its status – typically these map to sensors, actuators, or configuration variables like a setpoint. Alarming: modeling, routing, and acknowledgment of alarms. Alarms indicate a condition which requires notification of either a user or another application. Histories: modeling and querying of time sampled point data. Typically edge devices collect a time stamped history of point values which can be fed into higher level applications for analysis. oBIX 1.0 provides a low level object model which can be extended during implementation. While points are directly addressable (and thereby settable), direct interaction with the points requires too much knowledge of the underlying control system for the enterprise developer. The underlying points can be aggregated, the results named, alarm levels set, and histories begun using the oBIX contract. If oBIX exposes a low level object model for control systems, oBIX contracts create the higher level type libraries that most programmers actually want to work with.

Uses of oBIX

Tenant interactions To keep a public space open in the evening may require a range of calls to different organizations within a building, each initiating an interaction with a separate building control system. To schedule a public meeting tonight from 7:00 to 9:00, the organizer may have to:

Call Security to warn the guard, and keep the (1) Access Control System working in day-time mode until 9:30. The guard may also need to disable the (2) Intrusion Detection System during that period. Call Maintenance to make sure the room's (3) Environmental Controls are set properly for the event. This may include over-cooling (or heating) the room in advance to make sure that the room will be comfortable when filled with the anticipated numbers of callers. Call the media support group to make sure the (4) A/V Event Management system is properly warmed up before the event, In an oBIX-enabled building, these features are accomplished by instead sending an iCalendar meeting invitation to the room and/or its support systems.

Emergency response The Common Alerting Protocol (CAP) is a standard increasingly used for relaying information from various agencies to the public and to police and first responders. One challenge that public notification faces is that the traditional Emergency Broadcasting System for transmitting information over the radio is now much less effective, now that the public is tuned instead to personal media players such as the iPod. New versions of these protocols anticipate, for example, direct texting of all cell phones in range of a given cell tower or set of cell towers. In a similar manner, current proposals suggest direct messaging to Intelligent Buildings to invoke named oBIX contracts, with effects ranging from temporary user security elevation, to initiating process shut down, to notifying in-building warning systems to read messages aloud. The Open Geospatial Consortium anticipates Emergency Responders being able to access certain classes of geo-tagged sensor information from buildings from within their maps to improve situational awareness.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with OBIX

Start with the simplest possible case. Write down what OBIX claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to OBIX before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about OBIX ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of OBIX

In research: OBIX appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses OBIX in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: OBIX is common in secondary-school and first-year university syllabi. It links to neighbouring topics Building automation, Standards, so understanding it makes those chapters shorter.
In everyday life: Look for OBIX outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study OBIX in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what OBIX means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain OBIX out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is OBIX in simple terms?

oBIX (for Open Building Information Exchange) is a standard for RESTful Web Services-based interfaces to building control systems. oBIX is about reading and writing data over a network of devices using XML and URIs, within a framework specifically designed for building automation. Building control…

Why does OBIX matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study OBIX?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on OBIX.