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PICList
Thread
'[PICLIST] [PIC] network'
2000\08\15@022324
by
Ake Hedman
|
Hi again, long time no see,
I need some oppinions on a problem of mine.
I have had pic controlled devices arround my house for several years ( a
boiler, light control etc etc ). As my house is located in the deepest forrests
of Sweden there is often problems with lightning strikes, but even if the phone,
some hubs and a computer burns once in a while the pic devices handled this
alright.
So I designed the M.U.M.I.N. RS-485 network ( http://www.brattberg.net/mumin)
and connect the devices to each other through a simple RS-485 network. Suddenly I get all sorts of problems when there is a thunder storm. Temperature sensors
get burned, pics get burned. The only thing that seeme to handle it all is the
75176 RS-485 transivers I use. They always survive.
I have tried to power the nodes locally and from a central point in the house
and get the same effect. Possibly there is a better chance to save the pic
itself when there is a central supplied power. I have a feeling this is true.
What is the best way to make a design that handle situations like this?
/Ake
===============================================================================
Ake Hedman, Systemarchitect Phone: +46 26 546691
Utilator AB Fax: +46 26 546681
Box 1405 spam_OUTake.hedmanTakeThisOuT
utilator.com
801 38 GÄVLE http://www.utilator.com
SWEDEN
Carpe diem quam minimum credula postero ===============================================================================
-------------------------------------------------------
-- ===============================================================================
Ake Hedman, Systemarchitect Phone: +46 26 546691
Utilator AB Fax: +46 26 546681
Box 1405 .....ake.hedmanKILLspam
@spam@utilator.com
801 38 GÄVLE http://www.utilator.com
SWEDEN
Carpe diem quam minimum credula postero ===============================================================================
--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics
2000\08\15@184729
by
Andre Abelian
|
/Ake,
1. put the board in metal box and ground it.
2. all inputs and outputs from the pic should be isolated.
3. every input that communicates with external world should have 0.01 cap
connected with ground.
4. use TTL parts mostly
5. the power supply input should have series resister connected with ziner
diode.
6. every external wires should be shielded if you can.
7. 4 layer board with power and ground plane.
8. in your roof add a big metal piece and ground it.
if you did all of this and didn't help you better move out.
Andre Abelian
> Hi again, long time no see,
> I need some oppinions on a problem of mine.
>
> I have had pic controlled devices arround my house for several years ( a
> boiler, light control etc etc ). As my house is located in the deepest
forrests
> of Sweden there is often problems with lightning strikes, but even if the
phone,
> some hubs and a computer burns once in a while the pic devices handled
this
> alright.
>
> So I designed the M.U.M.I.N. RS-485 network
http://www.brattberg.net/mumin)
> and connect the devices to each other through a simple RS-485 network.
Suddenly
> I get all sorts of problems when there is a thunder storm. Temperature
sensors
> get burned, pics get burned. The only thing that seeme to handle it all is
the
> 75176 RS-485 transivers I use. They always survive.
>
> I have tried to power the nodes locally and from a central point in the
house
> and get the same effect. Possibly there is a better chance to save the pic
> itself when there is a central supplied power. I have a feeling this is
true.
>
> What is the best way to make a design that handle situations like this?
>
> /Ake
>
>
>
============================================================================
===
> Ake Hedman, Systemarchitect Phone:
+46 26 546691
> Utilator AB Fax:
+46 26 546681
> Box 1405
ake.hedman
KILLspamutilator.com
> 801 38 GÄVLE
http://www.utilator.com
> SWEDEN
> Carpe diem quam minimum credula
postero
>
============================================================================
===
> -------------------------------------------------------
>
> --
>
============================================================================
===
> Ake Hedman, Systemarchitect
Phone: +46 26 546691
> Utilator AB
Fax: +46 26 546681
> Box 1405
.....ake.hedmanKILLspam
.....utilator.com
> 801 38 GÄVLE
http://www.utilator.com
> SWEDEN
> Carpe diem quam minimum credula
postero
>
============================================================================
===
>
> --
> http://www.piclist.com hint: The list server can filter out subtopics
> (like ads or off topics) for you. See http://www.piclist.com/#topics
>
--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics
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