I need your help on sending files to an old CNC machine. It only has an RS232 plug for communication.
I want to make an ARDUINO box that can send the files to the machine. I also want to use a USB stick to send and receive the files to the machine. I have an ARDUINO uno board and a RS232 shiled. I am going to purchase a USB shield and an LCD shield. I will use the USB shield read the USB and the LCD to navigate the directory of the USB stick and select the file I want to send to the machine. The RS232 shield will transfer the file to the machine. Will this set up work? Or is there any other hardware I would need to get his to work? Any help would be appreciated. Thanks in advance.
Like any design project, you should break this down into a sequence of subtasks. First, you need to read the directory on the USB stick. Whether or not that is possible probably depends on whatever library is used with the USB shield. I don't doubt that you can display file names on an LCD, but what kind of LCD? is it big enough so lines won't have to wrap, which makes reading file names awkward. Now does the USB library support reading a file in as bytes? And is the RS232 link from your CNC machine well documented? After all, some RS232 links use more lines than others, so that must be compatible with your RS232 shield.
After you have studied these major issues, you might have insight into whether you're planning this with compatible parts. I get the impression that you are just starting with Arduino, and this isn't an elementary project. You might plan some lesser projects which test the various functions you need individually. Trying to glue all this together at once is not a good idea.
This sounds like a project for a PC (or Raspberry PI) rather than an Arduino. You can easily get USB-RS232 converters. Why not use a cheap laptop - comes with keyboard and screen and an un-interruptible power supply as standard.
If you are set on using an Arduino you should be aware that the USART on the Atmel chips does not produce or respond to either RTS or DTR and your CNC machine may expect that. Also the serial ports on an Arduino operate at TTL voltage levels and you will need something like a MAX232 to convert to RS232 voltage levels.
...R
Does your old CNC machine have a console with screen and keyboard that interacts with the communications? Do you know the maximum size of your CNC text files?
Paul
Thanks guys for all of your insight. It has been a great help. I will do more research on the machine's RS232 capabilities. And I know this is a big project for a beginner like me. But it is good that you guys gave me a reality check. I will try to tackle one thing at a time. I will keep you guys posted. Thanks