hi i am trying to learn about practical microcontrollers for process contro at my university and would like some real world examples from practisin engineers. For fire alarm systems for example you would have a contro panel with sounders connected. Are these the main components of th control panel?
- a 16 bit microcontroller
- external memory
- LCD screen
can someone be give a more detailed explantion of these components i true, eg what microcontroller?
8 bit micro, 256 internal ram, 4k code.
0r let's say under appox 3$ from digikey and 2 line alpha numeric display
1MHz clock. 20mA max operating current
You need to learn much more when you are hardware challenged as you can get away with murder with your list.
yes that is good thanks. But i want a example of what is currently use ny a manufacturer. If the system was for a large building would not the use a 16 bit micro?
Andrew, you need to specify your requirements better. You went from a possible simple example to a potentially huge complex example. Martin answered for a simple case which is adequate for a home or small office. There is almost no end to the possible options that you could ask about. Is a large building a 100 story office tower, or a single story warehouse? The answer could take this from an 8-bit embedded application up to a very complex system using multiple PCs, data collection processors, networks and all kinds of sophisticated sensors.
Even on the small end, you have to decide whether a single or dual line character display is what you mean by LCD, or is it a color graphics display. What does it do when there is an alarm condition? Simply sound an alarm or dial a telephone and send voice or data message?
Control panel with sounders does not cleary indicate an LCD. A simple on/off switch and a LED would qualify as a control panel. There would be no need for the LCD or even the processor. The unanswered question is what does the control panel do?
Remember, the better you define the problem, the easier it will be to determine the answer.
The simplest fire alarm panels don't use a microcontroller but the more complex ones do. There are systems that are so complex that they need a great many zones (each with their own local panel) and an extensive network of signal wiring.
In developing a specification for a system you need to be extremely clear about the goals you want that system to achieve in terms of functions to be performed and how well the system needs to perform in fulfilling those functions.
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Paul E. Bennett...............
"a_edwards" skrev i meddelandet news:uOOdnev-2JXo8EvanZ2dnUVZ snipped-for-privacy@giganews.com...
Yes, it is not well known but if the building has more than 8 levels, you *have* to use a 16 bit controller or better! If it goes beyond 16 levels, you have to move up to a 32 bitter ;-)
If I hadn't been so lazy, I would have applied for a U.S. patent for using a 32 bit MCU in a fire alarm if the building has more than 16 levels. I am sure it would get approved...
Either that is utter nonsense or I am missing something. There is no relation between interrupts available and 'levels'. There is a relationship between code complexity and levels. And someone has to decide how to break up the interrupts. But one would suffice, combined with suitable i/o.
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[mail]: Chuck F (cbfalconer at maineline dot net)
[page]:
No, I think you'd definitely need a 32-bitter if there are more than
16 floors (including penthouse, basement and sub-basement levels). They must use something like ganged 64-bit processors for Taipei 101. Best regards, Spehro Pefhany
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"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
As a hint for CBFalconer, I think someone aleady mentioned that the ideal choice for marine process control, would be a floating-point processor. Simiarly, for land base station design, a fixed-point CPU is a natural choice, and for a mobile, GPS system that can work on land, or sea, (and on various building floors) you would need a mix of fixed point, floating point, and for future-proof, probably a 128bit processor.
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