BACnet in security systems.
Modern globalization processes constantly require greater unification and integration, which, in turn, should entail a reduction in costs.
Whether this is really so (in terms of costs and overall benefit), no one can say for sure now.
Since these processes often have a downside in terms of social, cultural and other changes that can cross out all the expected benefits.
I will also not be responsible for all areas of human activity.
But as for security systems, I am confident I declare — integration is a really useful thing.
Many articles have been written about the mutual integration of various security subsystems, although I am sure this topic is far from exhausted.
Nevertheless, in this article I would like to raise the topic of integration tasks to a higher level: the integration of the security system into the general dispatching and facility management system.
In general, when you look at this large, extremely diverse and, most importantly, open world of automation (we are talking about the automation of buildings, industrial facilities), you just start to envy.
And everything works and fits together, but in security systems, wherever you look, there is practically a wedge everywhere. Integration based on «dry contacts» is everywhere.
Perhaps, this can somehow be explained by the fact that security systems themselves should be more closed in order to reduce the likelihood of unauthorized information intrusion.
But this, of course, does not make things easier, and modern integration technologies provide information security at the proper level.
So, in order to keep up with modern automation technologies and bring security systems up to the required level, in my opinion, it is necessary to use already developed technologies for integration.
One of the most interesting and promising such technologies is the BACnet network protocol.
BACnet is an open building automation and control protocol developed by ASHRAE (American Society of Heating, Ventilating and Air-Conditioning Engineers).
The protocol was recognized as an ASHRAE standard in 1995, and in 2003 it became an international ISO standard (16484-5).
As is clear from the name of the protocol (BACnet – Building Automation and Control network) and the organization that developed it, this solution is intended primarily for working with engineering equipment in Denmark.
However, security systems were not neglected either – BACnet supports operation with fire alarm and access control systems.
BACnet networks
Based on BACnet, peer-to-peer networks are mainly built, except for the case when the master-slave mode (MS/TP based on RS-485) is used as the channel layer. Peer-to-peer is an important feature for control systems.
The absence of a dedicated server for network management significantly increases the survivability of the system as a whole.
To build networks of virtually any size, BACnet provides for the use of special network equipment: a repeater, a bridge, and a router.
They basically perform the same tasks as similar equipment for IP networks. By the way, BACnet is now often used over the IP protocol.
Transmission medium
BACnet can be implemented on various physical transmission media.
Thus, the protocol itself is untied from the transmission medium, which, in my opinion, is an undeniable advantage.
BACnet can work over Ethernet, ARCNET, MS/TP (RS-485), PTP (RS-232) and Lonworks. If we talk about security systems, the most relevant are Ethernet and RS-485.
BACnet Objects
The main logical entities of the protocol are the concepts of object and object properties.
An object describes specific physical and logical devices, and object properties transmit data about the state of any network object.
For example, an object can be a binary input, and its properties describe the physical state of the input 0 or 1.
The protocol supports more than 20 types of objects, which are designed to describe most standard elements of application equipment of various functional purposes. Such a unified approach allows implementing the interaction of any equipment that can present a description of its operation through BACnet objects.
For example, I will give several standard objects: analog input, analog output, binary input, binary output, etc.
To work with objects and their properties, the BACnet protocol describes special services, each of which performs a specific function.
For example, to access an object and its properties, the following services are available: create object, delete object, read property, write property.
To control a remote device and transfer data between devices, the following services are intended: transmit message with confirmation, transmit message without confirmation, device search, device response, and many others.
BACnet objects for security systems
How can we integrate a security system into a general control and dispatching system?
Of course, using BACnet objects. Here are the special objects of interest to us in the protocol:
Life Safety Point Object Type – describes a detector (sensor) or actuator of the security system
Life Safety Zone Object Type – describes a group of sensors or zones of the security system
Access Door Object Type – describes the door equipment in the ACS (lock, door contact, request to exit button)
Access Point Object Type – describes the access point in the ACS (door, gate, turnstile, etc.)
Access Zone Object Type – describes the access zone in the ACS
Access User Object Type – describes the ACS user
Access Right Object Type – describes the rights of the ACS user
Access Credential Object Type – describes the ACS user identifiers (proximity card, PIN code, etc.)
Credential Data Input Object Type – describes the device for reading the ACS user identifiers (card reader, keyboard, biometric reader, etc.).
From the objects listed above, it is clear that the protocol almost completely reflects everything related to fire alarms and access control systems. Now let's see how all this goodness can be used.
Integration with engineering systems
The ability to link a security system with other systems installed at the facility can provide tangible dividends from increasing the overall operating efficiency.
Of course, you need to understand that in our case, all connected systems must be able to work via BACnet.
If we talk about fire alarms, then first of all this is integration with the ventilation system.
In the event of a fire, it will be possible to quickly change the ventilation mode in order to prevent air flow to the fire site, or to organize smoke removal.
In addition, in the event of a fire, it will be possible to turn off the air conditioning systems or de-energize part of the facility.
The security alarm system can transmit information about the state of security zones to BACnet devices.
This is convenient to use for automating the management of life support systems. For example, after arming, the main lighting is automatically switched off, the power of ventilation and air conditioning systems is switched off or reduced.
When disarming, the necessary systems are reactivated.
This approach can significantly reduce the energy consumption of the facility, which will allow you to recoup the costs of integration in the shortest possible time and generate profit in the future.
The access control and management system can report on the number of people in a particular room.
Based on this information, the life support system will promptly change the ventilation and air conditioning mode to maintain an optimal microclimate.
Moreover, as mentioned above, BACnet devices exchange the necessary information directly with each other.
This does not require the intervention of upper-level control computers. It is clear that this significantly increases the reliability of the systems as a whole.
Single control center
Combining systems for joint automatic operation is great. Increases efficiency, reduces costs.
But the same can be implemented at the upper level. Everyone is talking about the idea of creating a single dispatch service now.
Well, then, please create it.
Within your facility, you can bring all systems to a common control workstation, from where the operator will receive information from all equipment.
Of course, it is not necessary to bring everything to one computer. For large facilities, several workstations will still be organized.
But these will not be separate posts for a security guard, a ventilation and air conditioning engineer, or an electrician.
This will be a single system where each specialist is provided with all the information and management tools necessary for work and timely correct decision-making in the event of any emergency situations.
Application software for organizing such workplaces is usually developed on the basis of SCADA systems.
These are specialized software tools for collecting, processing, displaying and archiving information about the control object.
Everything would be fine if…
In conclusion, let's look at the realities of life.
Currently, most security systems on the market do not yet have the ability to work in BACnet networks. This is especially true for equipment in the lower price segment.
Engineering equipment that supports BACnet, of course, exists, but, as a rule, it is also not cheap.
Designing and commissioning such an object, when competent engineers are needed, will probably also be more expensive than conventional solutions.
Of course, during the operation of the object, all these additional costs will pay off.
But we often do not look so far ahead at the stage of coordinating the project estimate, and progressive, but more expensive solutions do not always find support from the customer.
Nevertheless, I am sure that the future belongs to fully integrated solutions.