Many businesses are faced with the decision of choosing a building management system (BMS) and security system. However, there are certain criteria that might not seem that critical initially but are paramount when considering that system lifecycle costs are only realised after installation.
Neil Cameron, controls division manager at Johnson Controls, highlights the considerations when choosing or upgrading a BMS and access control solution and how future costs may be limited through forward thinking and planning.
There is a great misconception among business and building owners that a sophisticated access control solution is able to handle many aspects of building management. This is supported by claims from various access control manufacturers; however, it is not necessarily so when delving a little deeper into inter-functionality issues.
Fundamentally, there are different requirements between access control and BMS systems, just as a home and storeroom have different design parameters. An access control system operates on a different platform to BMS as it uses a secure database where realtime data is not emphasised. The values are essentially limited to binary values or states, which is the order of the day for an access control solution.
BMS on the other hand focuses on analog values; trending; PID control algorithms; energy management and integration with many airconditioning processes; and lighting and electrical processors, all operating on a realtime basis with closed loop control algorithms and time-sensitive deterministic data being the focus. Put simply, this is to ensure the building operates intelligently and optimally, ultimately saving energy costs.
Accommodating for future growth
Most successful access control systems operate independently of BMS due to different operation requirements. It is common practise to have a separate access control system that has the ability to share strategic information with a BMS in order to make automated decisions and share alarm monitoring and graphical displays. Even though the differences between both systems are vast, they share one common element - data. However, not every access control or BMS solution is geared for sharing of data, which necessitates a degree of integration.
Future growth for these systems may be accommodated in two ways. Firstly, additional building functions can be incorporated by means of integration, which is generally only successful if tested and approved compatible products are used. Even so, this is sometimes difficult. Take HVAC control and monitoring for example. Typically, HVAC software takes years to be developed and compiled and the intended functionality can never be obtained with a few lines of code and driver development.
The most successful access control solutions have the ability to share strategic information with BMS. This is the second option for integrating the two systems. So how is this done?
Supported protocols are the key to this level of integration, making the data available across both systems and allowing one system to 'connect' to another.
The most important protocol is BACnet. This protocol allows sharing of information from system to system, eliminating the requirement for additional hardware or software. Developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), BACnet is emerging as a global standard. Yet many locally developed systems are unable to conform to any standard protocol.
Another protocol at the forefront is LonWorks. More limited in functionality than BACnet, LonWorks operates on the device level and allows dissimilar devices and controllers to operate over a common network.
However, it is not necessary to only use standard protocols as it makes the initial installation a costly exercise. It can make more sense to ensure the system has the ability to 'grow' with the company through the functionality to add other devices as and when the need arises.
Another option is to communicate to other proprietary or open protocols.
For example, take fire panels that use low-level proprietary protocols specific to each manufacturer, where existing drivers can reduce costs and time constraints. If the manufacturer has available drivers that are already developed, this prevents research and development (R&D) as well as teething problems and we are all aware of the headaches involved with R&D and beta testing.
Another advantage of utilising standard and open protocols also allows for one network infrastructure to be utilised. Controllers, both access control and BMS, should connect onto an Ethernet TCP/IP network, eliminating the cost for a separate network infrastructure. There are many benefits to this architecture.
Training is necessary on one system only and alarms are not duplicated, ie: building alarms and access controls alarms are monitored on one system. A singular graphical user interface is another benefit, allowing the control room to locate faults quickly.
It may not be as simple as you first thought when selecting an access control and BMS solution. However, conducting thorough research and establishing these interoperability issues will ease the mounting costs and problems that occur once systems are installed.
For further details contact Neil Cameron, Johnson Controls on tel: 011 886 8997, or e-mail: [email protected]
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