Building Management Systems
Visit any large shopping centre today and you will certainly find that behind the scenes is a control room with virtually all building services under the control of a security officer. The first thing that strikes the eye will be a bank of closed circuit TV monitors and this is the most obvious electroinc system that is taking care of the building and the people in it.
But there are many more systems which also end up in the control room or certainly close by. Fire Alarm systems, Access Control, Control and Monitoring of heating and air-conditioning plant. All these items are described under the umbrella of Building Management Systems.
We have to take care not to duplicate text that appears elsewhere on this website. Our history as Applied Microsystems really took off in the mid-70s with BMS systems which pre-dated the PC but now, of course, make full use of Windows to provide a user-friendly front end.
We continue to manufacture all component parts of a BMS system although competition is far stiffer now than it was when we started! However in several cases we build product for BMS companies who would otherwise be our competitors so we could be best described as an OEM, Original Equipment Manufacturer. We are not proud! We are quite happy to ship modules and software to clients who then re-badge them with their own company name and logo.
Our typical system comprises 3 parts:
This comprises one or more of the 094 (16 control outputs) and 099 (100 mixed digital & analogue inputs) cards.
The CM855 Processor
This provides the interface between the relatively slow PC and the high speed data on the 4-wire bus which connects all the outstations in the building. The CM855 is capable of running the building even when the PC is 'off line', for example if a component is being changed. The CM855 uses our recently developed SAM4 processor card which is basically a Motorola HC11 processor with loads of RAM, EPROM and Flash memory, the latter for permanent storage. The CM855 continuously polls all outstations in the building - a typical complete scan takes about 1 second, so the response time for a new event is never longer that that.
One long-standing feature of our BMS products in time control. One of our systems in the Middle East has outside lighting control which is adjusted month by month according to sunset times. This lends itself to lighting and event control in a number of types of location.
The PC Front End
In the early days before the PC arrived, the CM855 connected directly to a dumb terminal which showed text only. This was more than adequate at the time but now we have created a number of packages that take advantage of the graphics capability of Windows.
Typically a fire alarm system will need to show descriptive information on a new alarm and also a graphical representation of the location in the building. The Graphics on-line program does just that, with 3 zoom levels to enable a quick overview of the building. The offl-ine program is used to prepare the graphics backgrounds which are simple .BMP files (bitmap) such as would be created by Painbrush in Windows. The locations of the various alarm sensors are represented on the graphics as icons, each of which shows a different type of sensor. The icons can be generated and then dragged to the correct position on the graphic and this data is stored in the database for the whole building.
The limit on cable length for an outstation loop is 1km but sometimes a client requires a BMS system for a large site - an airport, for example. This is the reason we designed the CM336 leased-line modem. There is virtually no practical limit over which data can be sent - providing the line complies with normal telephone specification, data could be sent around the world or via satellite.
A New Product - January 2001
The CMC104 is a direct plug replacement for the Landis & Gyr RWF61.30 controller. The original L&G product is now obsolete of course, dating as it does back to the 1980s but there is no modern direct replacement - well, up till now, that is! Click here to view the datasheet.
Most of our BMS products may be used in a number of different ways, not just for building controls but also for event generation locked to time. This brief summary of our BMS products may give you an idea or two as to how we can provide control and monitoring for your next project.