Monday, March 15, 2021

H.264 vs H.265 vs H.266

 H.264 vs H.265 vs H.266

The most popular video codec right now is the H.264 standard since almost all media devices support it. Even video platforms on the web can’t help but add support for this codec, and for good reasons. YouTube, despite having its own, is beholden to H.264, and this won’t change for years to come.

Now, we do not expect it to be the top dog forever as more competitors come on the scene in hopes to replace it. The most notable would likely be the upgraded version, H.265, also known as HEVC (High-Efficiency Video Coding).

There is also the H.266 codec, but it differs a great deal when compared to the others we’ve just mentioned. Worry not, however, because we are going to explain each for your deeper understanding.

1] What is H.264 codec

This codec has been around since 2009, and for quite some time, it has been the standard. The codec is also known as AVC, MPEG-4 Part 10, and VC-1.

It’s a video compression standard that is designed to playback high-quality video at a small size than RAW and previous standards. We understand the compression ratio is twice that of MPEG-2, which is quite astonishing. It promises to provide high-quality content with no quality loss when compared to other standards. H.264 is used by most modern mobiles and 2K cameras.

Basically, if your file size is 88GB, H.264 compression can bring it down to a little over 800MB. Additionally, when compared to other compression technologies, low-bit rate plays an important role. In the end, users will save time when having to download or stream video content at any time.

2] What is H.265/HEVC codec

As you might be able to tell from the name, H.265/HEVC is the upgraded version of the previous, and it is designed to replace it at some time in the future. The new standard was released back in 2013, but only now has been getting huge support due to the rise of 4K. HEVC is promising a massive 50% bandwidth reduction compared to H.264 for the same video quality.

This will no doubt continue in the years to come as 4K televisions and monitors become more affordable. However, the big question right now, is, what makes H.265 the future?

Well, if you watch 4K content on YouTube, you should realize that it doesn’t hold a candle to the same video on a Bu-Ray disc. That is due to H.264 compression for the most part, and that is something the newer codec wants to solve.

From what we’ve come to understand, HEVC uses more efficient compression methods, therefore, the end content will showcase more detail and fewer artifacts. We all want this, which is why we cannot wait for more hardware manufacturers to support the future standard. H.265 is used by most modern mobiles and 4K cameras, and almost all new hardware now provides HEVC GPU acceleration.

Now, there is one big problem with H.265/HEVC right now. You see, it is quite slow if Hardware Acceleration is not in play. If you want to decode in HEVC, then a powerful computer is required. Intel 6th generation or newer, and AMD 6th generation or newer, are the CPUs you should consider when purchasing a computer for HEVC.

3] What is H.266 codec

In 2020, Fraunhofer HHI (together with partners like Apple, Ericsson, Intel, Huawei, Microsoft, Qualcomm, and Sony) developed. The world has yet to fully accept H.265 as the new standard where video codecs are concerned, but already H.266 is being touted Fraunhofer HHI, the company behind all three codecs.

At the moment, we understand that this new codec, also known as Versatile Video Coding (VVC), won’t improve video quality over its predecessor, but is expected to reduce the size. So in a sense, it is the same as H.265, but with a smaller footprint. H.266 is promising a massive 50% bandwidth reduction compared to H.265 for the same video quality.

When the H.266 codec is adopted in the future, people from around the world may have little problems with streaming 8K content on their favourite platforms. H.266 is used by most modern mobiles and 8K cameras

H.266/VVC is supposed to support: 

• Picture resolutions from 4K to 16K as well as 360° videos
• YCbCr color spaces with 4:2:0 sampling, 10-bit
• YCbCr/RGB 4:4:4 and YCbCr 4:2:2
• Auxiliary channels (transparency, depth, etc.) 
• High dynamic range (HDR) and wide color gamut
• Bit depths up to 16 bits per component 
• Fixed and variable frame rates
• Progressive scanning 

Monday, March 1, 2021

H.266 codec to reduce video sizes by 50%

H.266 codec to reduce video sizes by 50% 

A new video encoding standard that reduces video file sizes by 50% is set to become usable by the end of the year, allowing high-resolution footage to be saved with smaller file sizes and to be transmitted in less time. Versatile Video Coding (h.266/VVC) is the newest block-based hybrid codec from the Joint Video Experts Team (JVET), a group comprised of MPEG and ISO/ITU members such as Bitmovin and Fraunhofer HHI, and promises to vastly improve the compression capabilities of workflows for any organization within the streaming industry, including but not limited to, OTT, VR, AR, and many other providers. As fellow members of MPEG, the Bitmovin encoding team was eager to test the capabilities of the newest codec and the potential improvements it offered over its predecessor h.265/HEVC. The ultimate goal of the project was to determine the performance parameters of the VVC codec and the subjective visual quality enhancements that ensue. While Fraunhofer HHI claimed that the VVC codec promises to improve visual quality and reduce bitrate expenditure by around 50% over HEVC, we wanted to prove the validity of the statement.

Today, compressed video data make up 80% of global Internet traffic. H.266/VVC represents the pinnacle of (at least) four generations of international standards for video coding. The previous standards H.264/Advanced Video Coding (AVC) and H.265/HEVC, which were produced with substantial contributions from Fraunhofer HHI, remain active in more than 10 billion end devices, processing over 90% of the total global volume of video bits. Both previous standards were also recognized by collectively three Emmy Engineering Awards for contributing substantially to the progress of television technology.

Through a reduction of data requirements, H.266/VVC makes video transmission in mobile networks (where data capacity is limited) more efficient. For instance, the previous standard H.265/HEVC requires ca. 10 gigabytes of data to transmit a 90-min UHD video. With this new technology, only 5 gigabytes of data are required to achieve the same quality. Because H.266/VVC was developed with ultra-high-resolution video content in mind, the new standard is particularly beneficial when streaming 4K or 8K videos on a flat screen TV. Furthermore, H.266/VVC is ideal for all types of moving images: from high-resolution 360° video panoramas to screen sharing contents.

The new H.266 standard will also allow systems or locations with poor data rates to receive larger files more quickly, so movies, for example, will buffer less and play more smoothly. Mobile devices will also be able to send higher resolution files, or longer clips, without using so much data.
Fraunhofer says that ‘H.266/VVC offers faster video transmission for equal perceptual quality,’ so we shouldn’t see the difference between files compressed by H.266 and those compressed using H.265. H.265 also halved file sizes when it was introduced, as did the H.264 standard that came before that — and which is still in use today.

The new standard requires new chips to make the most of it, and the press release states that they are already in production and that Fraunhofer will release the software to allow the standard to be used in the autumn of this year.

Another factor hindering the evolution of an 8K ecosystem is the question of cable and broadcast support. At the moment, the broadcast industry is beginning to deploy ATSC 3.0 (Advanced Television Systems Committee/ also known by the moniker Next Gen TV, establishes an IP-based broadcast transmission system), a major revision to the Advanced Television Systems Committee. ATSC 3.0 supports features like 4K broadcasting, wide color gamuts, and HDR. The standard, however, is not targeting 8K and the rollout is optional. Unlike the mandatory transition from NTSC to ATSC, ATSC 3.0 deployment is up to individual companies. There’s no mandate to include an ATSC 3.0 tuner inside a TV, for example.

Also, ATSC 3.0 contains some features that “improve” targeted advertising. So hurrah for that.
At any rate, the rollout of ATSC 3.0 is going to be the major focus for broadcasters. It’s not clear which codecs will be used — there are a number of articles diving into why H.265 adoption has been so slow compared with H.264. It’s possible that the bandwidth improvements from H.264 to H.266 might be big enough to be enticing — a video that requires 10GB of storage when encoded in H.264 would theoretically only require 2.5GB when encoded in H.266 with no (again, theoretical) loss of quality.

Ericsson CTO Erik Ekudden’s view on recent developments in video compression technology

Continuous innovation in 5G networks is creating new opportunities for video-enabled services for both consumers and industries, particularly in areas such as the Internet of Things and the automotive sector. These new services are expected to rely on continued video evolution toward 8K resolutions and beyond, and on new strict requirements such as low end-to-end latency for video delivery.

This Ericsson Technology Review article explores recent developments in video compression technology and introduces Versatile Video Coding (VVC) – a significant improvement on existing video codecs that we think deserves to be widely deployed in the market. VVC has the potential both to enhance the user experience for existing video services and offer an appropriate performance level for new media services over 5G networks.

 

Sunday, February 14, 2021

Touchless Access Technology

Touchless Access Technology 

THE business landscape changing so dramatically over the past few months — possibly irrevocably — the task for many in security, including for consultants, integrators, dealers and manufacturers. As businesses and organizations begin to reopen, many are rethinking the way they budget for security, including access control, video surveillance and intrusion Alarm.

It’s amazing that a microscopic virus from China could virtually bring the world to a standstill. The 2020 global pandemic has reshaped the way people work, learn and play on every conceivable level. In addition to the devastating impact on global health and safety, COVID-19 has infected the health of the global economy.

The growing call to return to work will surely accelerate many of the social distancing, sterilization and occupancy issues that we are currently facing. Hopefully, modern medicine will rise to the challenge sooner than later with a COVID-19 vaccine, but this may take some time even with accelerated testing and approvals.

Commonly touched items that can cause the spread of coronavirus (and other infectious disease) can include things like elevator buttons, ATM and checkout keypads, door knobs and handles, keyboards and mice, and door/entry access control panels — just to name a few. When you think about all of the “touchable” items that you interact with each day it becomes a daunting task to stay away from them and feel safe, clean and virus-free. Well, it's no surprise that right now, businesses are feeling the need to provide solutions and upgrade their safety and security as the workforce begins to come back to the office or plan for that to happen soon.

By employing touchless credentials such as face recognition, proximity devices, or mobile credentialing, existing and new access control systems can easily be enhanced to provide a fast and efficient means of allowing authorized individuals hands-free entry and egress to a facility helping prevent the spread of contagions that can impact the health of both individuals and businesses. Taking the role of access control further, platforms with open architecture can integrate new thermal detection solutions to instantly identify the surface temperature of individuals.

Types of touchless technology

Businesses going touchless isn’t new—despite how relevant it is lately. In fact, touchless technology, from gesture sensors to voice recognition, has been widely used since the late 1980’s when automatic faucets and soap dispensers became popular in public restrooms. Today, you likely experience touchless technology multiple times a day such as walking through an automatic door, or asking Siri to set your alarm while your phone is sitting across the room from you.

Sign-in process

Touchless technology isn’t only about hygiene and safety. It’s also a way to show that your business is forward-thinking and modern. After all, who likes being slowed down by an old-school pen and paper sign-in sheet or a clipboard with long legal documents to read through?

The answer: no one. That’s why we have thought through how to make the sign-in experience seamless and touch-free. With a touchless visitor sign-in, guests can pre-register on their phone or computer before their arrival; scan a QR code at check-in; and be off to see their host in no time.

For modern offices, creating a touchless experience shows that you’ve thought of every last detail of your visitor experience and have made steps to take the burden off of guests when they come onsite. By doing that, you save your visitors time once they arrive so they’re not bothered with sign-in and can more quickly get to who they’re there to see.

Plus, while having one visitor come on site might seem simple, there’s often a lot of info you’ll need to collect from them. Instead of asking for this information during sign-in, you can collect essential information about your guest and take care of any additional actions before the visit, rather than frantically trying to solve issues while your guests wait in your lobby.

Going touchless is another way to help your visitors, and your entire office, stay healthy. By going touchless, you’re able to minimize the spread of germs and make sure you’re taking care of everyone in your space. 

Gesture recognition

Gesture recognition is the most common form of no-touch technology. Users can do simple gestures to control or interact with devices without touching them. Waving your hand to trigger an automatic door, for example, removes the need to touch handles or a physical button. Users are positively identified with a simple wave of either their right or left hand, in any direction. The touchless technology copes with wet and dry fingers, eliminates ghost images left on the scanner and mitigates hygiene concerns. The high speed, contactless acquisition capability allows users to remain in motion while being identified. Faster access control and time & attendance transactions reduce overall costs and increase employee productivity.

The system uses the passenger's unique Aadhaar identification number to biometrically authenticate passengers in real time, from arrival at the airport through boarding. Each checkpoint features high-speed and touchless biometric technology to facilitate the passenger processing. In less than a second, this device captures four fingerprints and matches them against the Aadhaar database.  An automated process generates considerable time savings for an airport like Bengaluru, which experienced a 22% increase in passengers in 2016, rising to 22 million. Passengers will be able to pass these checkpoints much quicker, and no longer have to constantly show their ID documents & boarding pass/e-ticket.

Bengaluru is the first airport to use a biometric identification process based on Aadhaar ID numbers, offering a thoroughly modern passenger experience that will contribute to the digital transformation of India. Indian passengers with a driver license (which also contains their fingerprints), and passengers with a biometric passport from other countries can also take advantage of this e-boarding system. When checking in, they are assisted by a police officer, who scans their passport and boarding card, and saves their fingerprints to ensure traceability.

Examples of this include smart lights that turn on when you walk into a room or automatic doors that you see at grocery stores, hotels, and commercial buildings.

Voice recognition

Voice recognition systems let users interact with technology simply by speaking to it. This has become popular especially in our homes. We can make hands-free requests, set reminders, and perform other simple tasks by talking to Apple’s Siri, Amazon’s Alexa, or the Google Assistant. You’ll be able to use an app to switch on light, or if that sounds a little awkward, even your voice – most systems will integrate with a virtual assistant such as Google or Amazon. One thing to check is that your lighting is compatible with the virtual assistant you use, as not all bulbs work with all systems.

Dozens of companies now offer smart door locks that are controlled via an app. With many of them, you can even control access with your voice using virtual assistants such as the Amazon Alexa®.

It’s also possible, with many models, to send electronic keys to friends and guests when they visit. These keys can be timed to stop working once they leave, giving you peace of mind.

With most virtual assistants, you’ll even be able to remotely operate your lights and set timers so it appears you are home even if you’re away. You can also set routines, so that the house lights up whenever you return home, and switches everything off as you retire to bed for the night.

Most smart TVs integrate with a virtual assistant, so you can turn on your TV or change channels using your voice – a particularly useful feature when you inevitably lose the remote down the back of the sofa, so it’s useful long after COVID-19 is a distant memory.

Facial recognition

Even before the COVID-19 pandemic, the touchless nature of facial recognition as an access credential was gaining traction with physical and cyber security professionals. By using an individual’s face as an access control credential, facial recognition eliminates the need and expense of physical cards and proximity devices, or the need to physically enter PIN codes. In addition, facial recognition readers meet the new emerging need to limit physical exposure to germs and viruses by offering a highly accurate touchless access control credentialing solution. 

As a workforce management tool, facial recognition helps preserve the health of employees checking into work, while providing management with an infallible means of documenting employee time and attendance while providing a detailed history of overall workforce activity and individual personnel tracking. Both of which have been longstanding challenges due to easily compromised time tracking systems and practices. Now, nothing is left to question based on hard data. 

With the growing popularity of facial recognition technology, there are many choices already available with more undoubtedly on the way. Selecting the right solution for your specific access control and/or workforce management application is dependent on a very wide range of variables. But there are a few core characteristics that you should look for when evaluating facial recognition readers.

Most facial recognition terminals employ some form of IR (Infrared) technology to help ensure high visibility by the unit’s image sensor. This often limits where the unit can be installed such as outdoors or near windows due to strong ambient light. More advanced facial recognition readers employ as many as 80 wide-angle near infrared LEDs and 60 narrow-angle near infrared LEDs, allowing the unit to recognize faces even in full daylight and brightly lit environments (not direct sun). This enables installation at indoor locations near windows, lobbies and building entries.  

Another facial recognition reader advancement to look for involves three-dimensional pixel intensity analysis. Ambient lighting contains ultraviolet rays which can negate near infrared LED lighting, and can also cast shadows making it difficult for a facial recognition reader to pinpoint the facial recognition points required for identification and authentication. Three-dimensional pixel intensity distribution analysis minimizes the effects of ambient light when acquiring facial images by minimizing lighting contrasts. As a result, it is easier for the algorithm to recognize the shape of the face enabling it to extract more facial features and create higher quality face templates, which are critical for accurate facial recognition. 

The angle and position of a facial recognition reader directly impact the performance of the unit. Facial recognition readers with different viewing angles for built-in visual and infrared cameras allows users to stand at positions that are most suitable for facial recognition with little or no effort of contortions. This results in a faster, more comfortable, and convenient user experience. 

It is most important that the facial recognition readers you evaluate are capable of analyzing faces in real time to maintain fluid entry/egress even during high volumes of employee traffic. Hardware-dependent live face detection systems employing technologies such as facial thermogram recognition and facial vein recognition require expensive hardware components, provide less accurate matches and slower authentication performance, which is counterintuitive for mainstream access control and workforce management applications. 

Thermal Camera integration is expected to enhance security and safety at sites by combining face recognition and skin temperature measurement with facial recognition hardware unit. It increased the accuracy and consistency of the temperature measurement by using the face recognition algorithm to pinpoint the upper area of the face. It displays skin temperature and thermal image of a subject’s face on its intuitive GUI, giving audio and visual alerts when higher than threshold temperature is detected.

Personal devices

For technology to be completely touch-free it must operate without the need for physical contact, like in the examples above. However, the introduction of smartphones and other personal devices have made nearly touch-free technology possible as well. Anything that operates at the command of your own personal device allows you to avoid touching public surfaces. The emergence of smartphones using iOS and Android is rapidly changing the landscape of the IT industry around the world. Several industries, such as digital cameras, car navigation, MP3, and PNP, have been replaced by equivalent or even better performance using smartphones. Smartphones provide increasing portability by integrating the functions of various devices into a single unit which allows them to connect to platforms with network-based services and offer new services and conveniences that have never been experienced before.

The combination of smartphones and access cards is creating a new value that goes beyond the simple convenience of integration enhancing the ability to prevent unauthorized authentication and entrance. People sometimes lend their access cards to others, but it is far less likely they might lend their smartphone with all their financial information and personal information – to another person. This overcomes an important fundamental weakness of RF cards.

Another valuable aspect of mobile credential is that it makes it possible to issue or reclaim cards without face-to-face interaction. Under existing access security systems, cards must be issued in person. Since card issuance implies access rights, the recipient’s identification must be confirmed first before enabling the card and once the card has been issued, it cannot be retracted without another separate face-to-face interaction. In contrast, mobile access cards are designed to transfer authority safely to the user's smartphone based on TLS. In this way, credentials can be safely managed with authenticated users without face-to-face interaction.

Mobile cards can be used not only at the sites with a large number of visitors or when managing access for an unspecified number of visitors, but also at the places like shared offices, kitchens and gyms, currently used as smart access control systems in shared economy markets.

While NFC could be an important technology for mobile credential that is available today on virtually all smartphones, differences in implementation and data handling processes from various vendors prevents universal deployment of a single solution to all devices currently on the market.

Accordingly, Bluetooth Low Energy (BLE) has been considered as an alternative to NFC. Bluetooth is a technology that has been applied to smartphones for a long time, and its usage and interface are unified, so there are no compatibility problems however, speed becomes the main problem. The authentication speed of BLE mobile access card products provided by major companies is slower than that of existing cards.

AirFob Patch addresses the need for technological improvements in the access control market in a direct, cost effective, and reliable way – by offering the ability to add high-performance BLE to existing card readers – enabling them to read BLE smartphone data by applying a small adhesive patch approximately the size of a coin.

This innovative breakthrough applies energy harvesting technology, generating energy from the RF field emitted by the existing RF reader – then converting the data received via BLE back into RF – and delivering it to the reader.

“For Indian workers to return safely back into office buildings, there must be a comprehensive system in place that integrates technology and new safety protocols both for the building and for tenant spaces alike. It can't be every building owner, tenant and occupant for themselves. We are all in the business of public health now to protect each other’s lives and help India get back to work”. - Arindam Bhadra

Iris

Every human iris has its own unique traits. An iris scanner identifies pits, furrows and striations in the iris and converts these into an iris code. Comparing this code to a database subsequently determines whether to allow access. Iris recognition terminals provide 100% touchless user authentication for a variety of applications, spanning access control, time & attendance, visitor management, etc.

Touchless Switches

Touchless wall switch makes opening a door simple and germ free. Blue LED back-lighting highlights the switch at all times, other than during activation. This provides a visual reference of the switch’s location in low light conditions. Its low-profile design makes it blend into your wall.

Touchless Visitor Management 

The visitor management system is the first point of contact for every visitor. To help maintain the spread of COVID-19, several organizations are implementing health screening procedures for visitors and employees entering their building.

Touchless technology doesn’t only provide protection and safety to the workplaces. It also provides the seamless modern experience to the workplace. The paper-based manual system is not safe enough and also slowed down the productivity of the business. That’s why we have thought through how to make the visitor check-in experience seamless and touch-free.

A.   With a Touchless visitor management system, visitors can pre-register on their smartphone before their arrival; visitor screening; check-in with a QR code; can meet their host in no time; and record the last details of the visitor experience.

B.   Going Touchless is a way to help your visitors, and your workplace, stay healthy. By going Touchless, you’re able to reduce the spread of viruses.

C.   The Touchless visitor management system saves your visitors time once they arrive so they’re not bothered to check-in and can more quickly get to who they’re there to see.

D.   When Visitors arrive, you can collect essential information about your guest and take care of any additional actions before the visit.

E.   Touchless Visitor management System isn’t only about hygiene and safety. It’s also a way to show that your business is forward-thinking and modern.

Kiosk

Companies have to now restart the Touchless visitor management system after lockdown is over. To help maintain the spread of COVID-19, several organizations are implementing health screening procedures for visitors and employees entering their building. Touchless self-check kiosk automatically measures body temperature in seconds. It is an invaluable solution for quick detection of illnesses and reduce the spread of bacteria & viruses, it vets staff members and the public before entry to premises such as Schools, Malls, Restaurants, factories, Railway stations, Airports, and Corporate offices.

The kiosk features a touch-less UV-C Box to disinfect the bag, cell phone, and keys in less than 10 seconds. UV-C Box kills 99% Viruses and Bacteria within 10 seconds on exposed surface.

Preparing before anyone even arrives onsite

There’s a lot you can do before your employees and guests arrive to make the experience frictionless. Start by pre-registering anyone coming into your office. This way you can gather important information to make sure they’re safe to enter and give them what they need to feel comfortable in your workplace.

Start with pre-screening them and approving their entry to make sure only the right people come on-site each day. This gives your team important control levers, like inviting healthy employees into the office in shifts.

Create a touchless sign-in experience.

A.   Post clear signage at the front desk so people know what to do when they arrive

B.   Allow people to check-in using their personal device rather than an iPad Kiosk

C.   Put a bottle of hand sanitizer next to your kiosk if you do need to use it

D.   Update your settings so guests don’t have to tap to take their photo when they arrive

E.   Create a welcome guide and customize it by employee or visitor type to make sure everyone has the information they need

F.    Make your badge printer easily accessible to guests 

G.   Update your hospitality practices. Instead of having a receptionist hand a guest a drink, make personal beverages available to grab without hand-to-hand contact

H.   Set up your final screen to give instructions to guests about what to do next, like where to go or where to wait for their host

I.    Opt for a sign-in system that notifies your employees automatically when their visitors arrive


Monday, February 1, 2021

DDC in BMS System

 DDC or Direct Digital Controller in BMS System

What is DDC ?

To understand the DDC, we need to know a little bit of history about what was the things before the DDC invention and why it was invented? So that we can have a broader view of the primary purpose of DDCs.

The Programmable Logic Controller or PLC used to control and monitor the Process mainly in the industry like automobile and other manufacturing factories.

Richard Morley invented PLC in 1968 to fulfil the primary needs of control and protect the production capacity of machines and manufacturing lines in the industry, and this PLC used initially was in the area of transfer lines in automotive plants.

Due to these PLC or Programmable logic controllers were designed and invented mainly for controlling and monitoring or automating the productions in the industry.

But when it comes to buildings, this PLC cannot fulfil the exact needs in terms of tenants comfort, environmentally green or can say effective management system for buildings. And still, we can use PLC for Building automation whereas it will be an excessive investment and different performance.

So here DDC or direct digital controller invented in order the process and automated the building equipment needs almost which PLC can do with minimal investment from installation to engineering.

What is the Main Difference between PLC and DDC?

What is DDC or Direct Digital Controller?

In a nutshell, DDC is a controller which use the analogue or digital signals from various devices of a field sensor and actuators and then process and control the system based on the programme written inside the controllers and has the capability to sends the information to another controller or DDC.

Basic Features of DDC

·       DDC or Direct digital controller usually has the followings features

·       The Analogue Inputs is to monitors the fields sensors values.

·       Digital Inputs to monitors the on/off status from switches/contactors.

·       The analogue output is to control the field actuators devices.
Digital Output is to control relay or provide low voltages.

·       DDC must have internal ROM/RAM to store control logic and sensor values.

·       It must have networking protocols inbuilt to transfer the data between the devices.

·       Modern DDC controller should have the capability to implement BACnet protocols for communication.

Note that there are various DDC controllers available in the market from the different manufacturer and those DDCs are available with a variety of function and features based on the specific needs like controller has all inputs/outputs like Analog inputs, Digital input, analogue output and digital output and some controller has only digital/analogue inputs.

Let us see below DDC Controller

·       Eleven 10-bit universal inputs whereas we connect either analogue input or digital input using a jumper select, eight binary outputs, and eight analogue outputs.

·       Terminal 23,24 used to connect other DDC controller to communicate between devices through BACnet over MSTP.

·       It has non-volatile memory used to store program and work independently.

·       It has the 24vdc used to give power for field devices.

Now Let us see how DDC used to control the BMS System,

Consider the followings scenario which we need to control and monitor through above DDC.

Let us say in Building, we need to control Pump control and control filling sequence through DDC whereas we have 2 Booster pumpS, one is for filling the water tank and other is to pump the water to buildings purpose to tenants like toilet etc.

This two-pump motor is controlled through the pump control panel by manually and it should work automatically based on the following sequence 

·       Pump-1 should run if the water level below the high level and stops once above the high level.

·       Pump-2 should run if the pressure on the supply line lesser than the defines let us say 2.5bar.

·       Pump-2 Should not run if water lesser than the lower level switch even pressure lesser than defined.

So based on the above sequence we will have following parameters to monitor and control

·       Booster pump-1 Run status from control panel-Binary Input

·       Booster pump-1 Run command from control panel-Binary output

·       Booster pump-2 Run status from control panel-Binary Input

·       Booster pump-2 Run command from control panel-Binary output

·       Water Low-Level status-Binary Input

·       Water High-Level status-Binary input

·       Liquid pressure on supply line-Analog Input

Let us connect the above points in DDC Controllers as follows

BP-1 Run sts- IN-1

BP-2 Run sts- IN-2

Low-Level Sts- IN-3

High-Level Sts-IN-4

Liquid Pressure-IN-5

BP-1 Run Command-BO-0

Bp-2 Run Command-BO-1

 

Logic will be as follows to execute the above sequence

 

If IN4==1        ##(means lesser than high-level status)

then

BP1=1             ##(On Pump)

else                 ##(means above than high-level status)    

BP1=0             ##(Off-Pump)

endif

 

If (IN5<2.5 and IN4==1)    ##( if pressure lesser than 2.5bar and water above the low-level sts)

then BP2=1     ##(on Pump)

else

BP2=0             ##(Off-Pump)

endif

 

Note that this program may change for each vendor controllers.

Not only this small sequence but also DDC can execute complex and critical sequence in BMS System for HVAC.