Post by thread:[PICLIST] [PIC] network

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.hedmanTakeThisOuTutilator.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

/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.hedmanKILLspamutilator.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