New ! Buy your CAS BACnet Explorer from Engenuity.
Starting June 2008, you can buy the CAS BACnet Explorer from Engenuity Systems. You may already know Engenuity for their LonWorks products – but did you know they have expanded their scope when it comes to open systems products such as BACnet?
Founded in 1994, Engenuity Systems, Inc. based in Chandler, Arizona began as a manufacturer focusing on contracted engineering and the development of LonWorks® interface cards, I/O products and drivers. As the company grew, it realized a need to provide customers with an effective way to purchase LonWorks® – based products worldwide. Engenuity currently offers more than 20,000 products from over 100 manufacturers for use in building automation networks, specializing in devices utilizing LonWorks® technology, a leading networking and communication standard; and various wireless technologies that extend the reach of control networks and applications for controllers, sensors, actuators and other devices.
Flavors of BACnet – Read more…
BACnet Objects and Properties – Read more…
IN THIS ISSUE
CAS Welcomes a new engineer – Johan Jacobs
Johan Jacobs joined CAS at the beginning of May. His primary focus will be embedded systems and Bacnet software development.
After his studies Johan started his career with Denel Aerospace Systems. They specialize in the development of guided weapon systems (eg. missiles). He worked on the A-Darter project which is the development of a new 5th generation air-to-air missile. Most of his work involved schematic design as well as PCB design. He was responsible for the four PCB’s which are located in the front gimbal of the missile, while under the supervision of his mentor. Johan had to write embedded C test software for the validation of our first prototype PCB’s and was also responsible for some of the documentation and design reviews. While he worked at Denel he also had the chance to attend a few courses on VHDL programming as well as hardware designing for EMI/EMC and one or two other courses.
Do you need to integrate TLC systems into BACnet, Lonworks or some other systems ? We have proven solutions. CAS have a FieldServer driver capable of connecting GE-TLC systems to over 110 other protocols. Our solutions include an option which allows you to connect your GE configuration computer via the FieldServer, sharing the connection to the TLC panels.
Just because a system has an XML interface does not mean you can use it. There are some very important questions you must ask in evaluating the usefulness of an XML interface.
XML provides a syntax and structure but imposes no obligation on how it must be used.
Consider the example of spoken language. English imposes rules on syntax and structure but does not oblige you to say anything useful or comprehensible to other people.
Data Transfer using English
Your assistant is likely to respond well to the 2nd instruction and not know how to respond to the first.
The same considerations apply to XML. Now consider an XML example:
Data Transfer using XML
Format example 1
< Data Xfer > < Send data now ! > < /Data Xfer >
Format example 2
< poll > < source > < nodeId > 22 < /nodeId > < dest > < nodeId > 11 < /nodeId > < nodeName > node_A < /nodeName > < /dest > < responseRequirement > dataOnly < /responseRequirement > < query > < action > read < /action > < tableName > Setpoints < /tableName > < address > 10 < /address > < length > 3 < /length > < /query > < /poll >
Its not hard to see that the success of the query is dependent on the ability of the system to understand the query. Just because it complies with the rules of the XML syntax does not mean the interface will understand it.
Here are some key questions to ask:
1. Is the XML interface implemented using TCP/IP or UDP?
2. What is the XML Schema? The schema provides the structure of the XML packets used to query and respond with system data. It shows how the messages must be formatted and defines the data types of the various message fields (in the world or protocols the schema is equivalent to the protocol specification).
3. All the other normal questions you would ask of an interface – What data is available? How much can be transferred at once? What is the scaling? How are data objects addressed? etc…
Where do the terms Cat5 and Cat5e come from?
TIA Telecommunications Industry Association, TIA defined standard TIA-568-B which defines the cables and structured or modular cabling systems and termination standards for building and telecom cabling systems.Cat5 and Cat5e Cable’s What is the difference?
Ethernet Cable Color CodingThere are two color coding standards. The color coding standard does not affect whether the cable is a cross-over or straight through patch cable. Color does not affect performance or use of the cable.
Read the Flavors of Bacnet article.
Data inside a BACnet device is organized as a series of objects. Each object has a type and a set of properties. There is always at least one object in a device – it is used to represent the device itself . The other objects represent the device’s data.
In practical terms think of a simple thermostat. Our example is a simple device that has a temperature sensor, allows the set point to be changed locally or remotely, has a local remote selection and reports there is an internal fault by reporting its status as normal/abnormal.
Read the BACnet Objects and Properties article.
2008 Chipkin Automation Systems – email@example.com
BACnet is a registered trademark of ASHRAE.