Hi everyone I'm upgrading an existing embedded system. This system has 1 serial port and DOS is runnig on it. But customers wanted this device to talk with other 8 devices over RS232(new requirement) First idea i came up with is ; finding a new card with 8 serial ports on it and integrate it to the former system.So that it would be the interface between existing system and other devices. But it costs too much(almost ~200$). Another idea , maybe a fantasy , is finding a RS232<=>RS485 converter .Then plug it to the output of other devices .So i can build a network . Then my application can successfully talk to others with just some software upgrade. Any ideas ? Best Regards.
Help wih design
Started by ●May 21, 2007
Reply by ●May 21, 20072007-05-21
tguclu wrote:> Hi everyone > I'm upgrading an existing embedded system. > This system has 1 serial port and DOS is runnig on it. But customers > wanted this device to talk with other 8 devices over RS232(new > requirement) > > First idea i came up with is ; finding a new card with 8 serial ports > on it and integrate it to the former system.So that it would be the > interface between existing system and other devices. > But it costs too much(almost ~200$). > > > Another idea , maybe a fantasy , is finding a RS232<=>RS485 > converter .Then plug it to the output of other devices .So i can build > a network . Then my application can successfully talk to others with > just some software upgrade. > > Any ideas ? > Best Regards. >Good idea, but only half thought thru. How would one of the external devices know you are talking to it ? Each of the eight devices would need an address and someway to toggle the direction of the RS485 line. A small micro board with two serial ports attached to each device ( total of eight) would work. One serial port talks to the local device and the other serial port talking RS485 and handleing the addressing of the eight devices. $200 / 8 = $25 per device and a RS485/RS232 comverter for the master DOS system. It might be cheaper and less programming to use the $200 solution. Unless you can convince your customers to pay for the programming involved. My $.02 donald