Alexey Starinsky wrote: >Hello, Erik. > >You wrote 5 May 2005 y., 15:11:05: > >Erik> Hello, >Erik> I have an idea to control a hydraulic system with software. Now I would >Erik> like some suggestions for hardware and software. Sorry for my bad >Erik> english, but I barely know what these things mean in swedish yet. I have >Erik> never done anything like this before. > >... skipped ... > >Erik> If you have done anything like this before, or know where I can find >Erik> more information or know about some more specialized mailing list, I >Erik> would appreciate your suggestions. > >Let me intoduce myself - I am an professional electronics engineer and >regularly solve such a tasks at work. > > Hello!
>First, let me make some comments: >You assume to make the Linux (or any other OS) to run the programm >and make all control that you need. > >Your idea pros: >+ It seems very simple - just to write control loop that reads the >sensors, and operates axtuators. Just a simple program in C/C++ > >Your idea cons: >- Just imagine the situation when your PC hangs or just need reboot: >control loop (sensors - actuators) can operate unexpectedly. >Of cource, if reboot is intended, you can disconnect any >driver/actuator manually, but that still does not help if PC behaves >unexpectedly. > > A working PC with Linux very rarely hangs (for me so far), mostly when running something in X. And even if it would hang, I believe the physical the damage would be limited in my case. >I suppose you need embedded solution that can operate even >independently without PC, but can be controlled and monitored from it >if needed. > > I do not really need it to operate it without PC. It is OK to have a PC connected to the device all the time I use it. And if I sometimes for some reason I can not have a PC connected, I can handle it manually, like I do now. >Typcally embedded solution is a board with microcontroller that makes >all control with typically the simple program inside. Board can have >any interface you want: (simplest is COM - RS232, USB is also >possible) and can be /monitored/controlled using PC via any custom >protocol + custom programme on desktop. > > Yes, someone mentioned PLC. I will look around to see if I find anything that can be bought here in Sweden. I saw on freshmeat that all Free Software related to PLC seem to be designed for a device called "Allen Bradley ControlLogix". I do not know if that can be bought here. >Also, it can be operated and controlled independently - via keyboard + >any smaller/bigger LCD as a display. > > Yes, a small keypad and display would be good, to enter numbers and select commands from a menu. It would not have to be larger keypad/display than on for example a texas instruments calculator (TI-83). >Usually I make all nesessary hardware by myself (schematics, PCB, >assemly, embedded software, e.t.c.), as all modules that are sold on >market are fairly expencive (if compared with actual cost of electronic >parts that are installed on that hardware). > >If you want, I could help you with your task. > Thanks for my offer! If I get started with something I will most likely have questions. I assume it would be difficult for you to help me in any other way than by email, unless you happen to live nearby (but I assume you live somewhere in Russia). The device is a verys small-scale portable sawmill, which I bought used last summer and intend to use when time permits (currently during the summer holidays, because I study engineering away from home the rest of the year). -- [email protected] mailing list
