KNX Topology — TP1 256 — What is it?
The KNX association have recently updated the topology to allow 256 devices per line without the need for Line Repeaters. This is due to a change in how bus couplers work and there now being enough products in the market to change over to the new format.
Revised KNX Topology
Specifically there are now enough TP1-256 Bus Couplers which take advantage of newer electronics to the reduce the data load of the device, meaning KNX telegrams can pass through more Bus Couplers before the telegram starts to lose its integrity.
The older TP1-64 Bus Couplers are still completely supported, as is using line repeaters on a line. However, If you are using the older bus coupler (TP1-64) in a topology with 256 devices per line, each TP1-64 device is the equivalent of 4 x TP1-256 devices. So to calculate, it’s the no of TP1-64 devices x 4 plus the TP1-256 devices. As long as the total of 256 isn’t exceed the line will operate correctly.
This doesn’t change the way KNX Power Supplies work and the normal load calculations still need to take place. Given the majority of KNX Power Supplies are 640mA or less, most KNX lines will still have around 64 devices on them. Once the load limit is reached you will need to create a new line or use a line repeater to create a segment, as per the old topology.
There are some manufacturers creating larger KNX Power Supplies, such as the Gira 1280mA, which allows you to take advantage of this update to the KNX Topology.
We have confirmed with our key manufacturers, and the majority of products we sell have the newer electronics, so there are no issues with moving over to the new topology immediately.
If you you have any questions about this or would like specification support on any of your projects, please get in touch with the sales team.
The New KNX TP1-256 Topology: more devices and fewer line repeaters
By Mark Warburton, Ivory Egg.
The KNX Association has recently announced the completion of a long-running project to update the system topology in order to make KNX even easier and simpler to use. Until now, the smallest part of the topology is a line segment with 64 devices. To expand the line, line repeaters can be used to add 4 segments together to create a total of 256 devices on each line. The reason for these limits is to ensure the integrity of the KNX telegram as it passes through multiple devices.
With advancements in electronics, an update was made to the specification for how a device connects to the bus, which meant that KNX telegrams could pass through 4 times as many devices before the telegram would start to be affected. Known as TP1-256, this newer standard means a total of 256 devices can be connected to a single line without the need for line repeaters.
Over the last few years, the KNX Association has been monitoring the number of products using this new standard and has been waiting for the right time to make the change. As this has now happened, the KNX Basic Course has been updated to reflect the new topology with line repeaters mentioned as a legacy solution.
Another impact this change has is that the Line 0 (area line) and Area 0 (backbone line) can now have 256 devices instead of being limited to 64. This still needs to include any line couplers (LCs) connected to the line, but it further increases the flexibility of the topology.
The New KNX Topology
Compatibility
The great news is that the two types of bus coupling (BC) unit are completely compatible. In fact, we have all been using a mixture of the devices without knowing it. If you want to take advantage of the new topology and need to have a mixture of TP1-64 and TP1-256 devices, then the following formula should be used:
(4 x M x TP1-64) + (N x TP1-256) . Whether we will see even larger power supplies that could cope with a full 256 devices on a line remains to be seen, but for now, the number of devices is limited more by consumption of the devices than the topology.
The Gira 1280mA KNX Power Supply is an example of a power supply that takes advantage of the new TP1-256 topology.
Implementation
As a distributor working with numerous KNX manufacturers, we have done a quick check and found the support for TP1-256 to be near universal, with only a few older products and one or two manufacturers not working to this newer standard. But given the backwards compatibility and option to use the existing topology with line repeaters, we really don’t see this as being an issue.
Conclusion
Whilst this seems like a fairly arbitrary change, and one that has taken a few years to filter down from the KNX standard to actual products, it is another example of KNX having one eye on the future whilst ensuring the past is still considered. Or to put it another way, maintaining full backwards compatibility has always been a key strength of the KNX standard, but that doesn’t mean we that can’t take advantage of newer ways of doing things. It also simplifies system design and has the potential to reduce system costs, particularly on smaller projects – which can only be a good thing.
Mark Warburton is the Technical Director of Ivory Egg (UK) Ltd, a supplier of leading KNX products and provider of KNX training courses.
Tomorrow’s World: the power of KNX TP1-256
By Simon Buddle, Future Ready Homes.
Thursday night used to be quite a special TV night in the UK in the 1970s and 80s. Top of the Pops, the Old Grey Whistle Test and, of course, Tomorrow’s World. Many of you will have seen the 1989 Tomorrow’s World that was recently shared via social media, showing us what technology we might have in our homes today.
The fact that much of what was anticipated is now commonplace in a KNX home in the form of automated blinds, heating and reactive windows, is testament to how accurate those predictions were. The focus on reducing our fossil fuel consumption through better efficiency was particularly prescient – indeed a recently-finished job used the then-futuristic Aerogel to insulate a staircase on a four-storey external wall. The only exception is that whilst there are some inductive charging devices around, we’ve yet to see them embedded in the walls.
Powering KNX
The need for accessible power is also pertinent to KNX. The introduction of the KNX TP1-256 topology last year basically means that a total of 256 devices can be connected to a single line without the need for line repeaters. KNX TP1-256 has meant, for many, that we can largely forget about topologies, line couplers and power supplies – and I’d tend to agree when it comes to small systems – but there remains a good argument for creating separate lines on larger projects to protect the system against a single point of failure.
We are also seeing some new products come onto the market that don’t require a 230V supply to power them. This is great in terms of easier wiring in the control panel, but it does come with a trade-off in that the bus current draw is often higher as a result, since all the power to drive the devices’ circuits and relays comes from the bus rather than the 230V supply.
Bus power
Just look at this example in order to work out just how quickly you can run out of power on the bus. Let’s say we have a total of 15 rooms, each with a capacitive touchscreen keypad on the wall. These are rated at 20mA bus maximum consumption. Now add in, for each room, a radiator servo valve actuator also with a rated consumption of 20mA. With those 30 devices alone, we’ve instantly used up 600mA of our PSU, and that doesn’t take into account anything back of house in the control panels. Now, a good rule of thumb for specifying a PSU is to only ever drive it at 80% of its capacity. That means 512mA maximum for our 640mA PSU. I realise that typically they won’t all be drawing maximum power at the same time, but there will be times when they do; e.g. home/away routines could well activate all servos and displays.
Power supplies
KNX power supplies have been noted as almost indestructible by many of the old stalwarts of the industry. Whilst that may well be true, we shouldn’t rely on it as a design principle. If you under-specify the power supply, then put it in a cupboard where it will sit at maybe 50oC degrees 24/7 for the duration of its life, don’t be surprised if it comes back to haunt you!
The latest KNX TP1-256 power supplies can have two sitting side by side in parallel on the bus. That’s great, but it is still a single bus. If you need two power supplies, why not get a line coupler and split the system in half? This has the additional benefit of making the system more robust as you’ll only lose half the system if anything does go wrong. On the other hand, some manufacturers are now making a 1280mA PSU.
Bus diagnostics
There are power supplies such as those from MDT, that will output data such as bus voltage, current draw and overload via a telegram. That could be extremely useful in determining faults or just general diagnostics so that you can ensure that the bus is working within design parameters.
Uninterruptible power supplies and batteries
As the system grows, so should the concern for failures, and the best way to prevent these is to add in a battery to ensure the bus always remains healthy. There is a question as what equipment should continue to be powered in the event of a total power failure, and at design stage, it’s worthwhile exploring scenarios around this idea. If the power to the house fails, any safety and security devices should keep running, as should anything that has logic modules or large chunks of control running on them. But there’s no point keeping all of the modules controlling the lights and heating online. If the power failure is short-lived, they won’t matter.
Conclusion
So, we haven’t quite made it to the Tomorrows World of power being embedded in the walls everywhere. Perhaps it’s a timely reminder that as KNX systems become ever easier to design and install, we should still remember the basic principles of calculating bus load and being wary of loading too many devices onto a single line, even though we can.
A 640mA PSU doesn’t mean 64 devices, and likewise the 1280mA PSU should not mean 128 devices. There is better practice than calculating bus load in conjunction with the quantity of devices and then segmenting the system accordingly. That is a basic system design principle that will ensure tomorrow’s world runs as reliably as it does today.
Simon Buddle CEng MIET, is a consultant for Future Ready Homes, a specialist in BMS and ELV services system design.
Новый UMC C3 ridium Server в исполнении Фирмы UMC technology на DIN рейку.
Параметры:
Пластик и металл
Преимущества
iRidium Server подключается к оборудованию и передает ему команды от панелей управления. Панели управления подключаются к серверу для управления через него оборудованием, получения обратной связи, загрузки логов и базы данных.
База данных может хранить информацию о работе сервера и оборудования за весь период времени, когда сервер был запущен. Панель управления по данным из базы может выводить логи и строить графики изменения переменных сервера.
iRidium server предоставляет возможность удаленного управления объектом, получать уведомления (push, e-mail) о событиях в системе, сбора, хранения и обработки данных, генерации графиков и трендов.
iRidium server UMC c интерфейсом KNX TP1-256 работает как KNX/IP-шлюз и позволяет использовать проект ETS для загрузки конфигурации в KNX-устройства.
iRidium server UMC c интерфейсом RS485 работает как HDL/IP-шлюз, а также может быть использован для работы с Modbus RTU или Modbus ASCII.
Сервер UMC не предназначен для логгирования и хранения больших объемов данных. Это ограничение связано с применяемыми компонентами flash-памяти. Для нагруженных систем с функциями логгирования и интенсивным обменом данными используйте сервер на базе NUC Kit или Windows PC.
KNX (стандарт)
KNX — это открытый стандарт (см. EN 50090 , ISO / IEC 14543 ) для автоматизации коммерческих и домашних зданий . Устройства KNX могут управлять освещением, жалюзи и ставнями, HVAC , системами безопасности, управлением энергопотреблением, аудио-видео, бытовой техникой, дисплеями, дистанционным управлением и т. Д. KNX развился из трех более ранних стандартов; Европейский Home Systems Protocol (EHS), BATIBUS и Европейский автобус Установка (EIB или Instabus ). Может использовать витую пару (в топологии дерева , линии или звезды ), Powerline , RF или IP- ссылки. В этой сети устройства образуют распределенные приложения, и возможно тесное взаимодействие. Это реализуется через модели взаимодействия со стандартизованными типами точек данных и объектами , моделируя каналы логических устройств.
Стандарт KNX был построен на базе коммуникационного стека EIB на основе OSI, дополненного физическими уровнями , режимами конфигурации и возможностями приложений BatiBUS и EHS .
Установки KNX могут использовать несколько физических средств связи:
- Подключение витой пары (унаследовано от стандарта EIB. (Унаследованная ранее среда связи BatiBUS (TP0) больше не является частью спецификаций KNX).
- Сеть по линии электропередач (унаследованная от стандарта EIB. (Унаследованная ранее среда связи EHS (PL132) больше не является частью спецификаций KNX).)
- Радио (KNX-RF)
- IP (также называемый EIBnet / IP или KNXnet / IP)
KNX не основан на конкретной аппаратной платформе, и сеть может управляться чем угодно, от 8-битного микроконтроллера до ПК, в соответствии с требованиями конкретного здания. Наиболее распространенная форма установки — через витую пару.
KNX является утвержденным стандартом следующими организациями, ( среди прочего ): [1]
- Международный стандарт (ISO / IEC 14543-3)
- Европейский стандарт ( CENELEC EN 50090 и CEN EN 13321-1)
- Стандарт США ( ANSI / ASHRAE 135)
- Китай Guobiao (GB / T 20965)
Он находится в ведении KNX Association cvba , некоммерческой организации, регулируемой бельгийским законодательством, которая была образована в 1999 году. По состоянию на 1 июля 2018 года в KNX Association было зарегистрировано 443 члена-поставщика оборудования и программного обеспечения из 44 стран. 77 000 компаний-установщиков в 163 странах и более 440 зарегистрированных учебных центров. [2] Это открытый стандарт, не требующий лицензионных отчислений, поэтому доступ к спецификациям KNX не ограничен. [3]