It is confusing indeed. I have a HAAS CNC machine. The documentation specifically states that interaction can occur only through an RS232 port. Moving on, I connected the female DB 25 at the HAAS CNC using a null modem 25 to 9 and an RS232 to USB(initially). This connection worked perfectly when i connected it to my PC(USB at the PC). What the CNC does is: I send a command from my PC and the CNC spits back corresponding data. Now all of it works perfectly fine.
But now I want to replicate the entire thing on a BBB. So that instead of my PC there is BBB. I know the exact null modem + RS 232 works fine with my PC. But is not working at all with the BBB. No handshake protocols are enabled. I have triple checked that just to be sure. >From what i think at the BBB :it should be DTE since at PC it is. I can try making it DCE. On Sun, May 22, 2016 at 8:47 PM, Bruce Boyes <[email protected]> wrote: > @Shaurabh > OK they actually have a pretty nice document for that! > > Now what is your CNC machine? What serial port document do you have for it? > > The serial cape has only TXD and RXD driven, no handshake or flow control. > The CNC might expect something specific. It does look like the serial cape > has some of the control signals fed back, I did not study it enough and map > the 5x2 ribbon cable to the DB9 to figure that out. > > You would need a null modem cable between the BBB DTE serial port and the > CNC DTE serial port, or you can modify the BBB serial as DCE instead. If > you make the BBB as DCE, and connect a straight serial cable to your PC > DTE, you should see the BBB bootloader information every time BBB powers > up. And you can log in to BBB on that serial0 port too. > > If things are eventually connected correctly to the CNC, it will also see > the BBB bootloader information: is that OK for the CNC or will it get > confused? If the CNC sends some data to the BBB during bootup it could > confuse BBB. > > So it might be better to use serial4, set as DCE which has no BBB debug > use already. > > If you do that, you could connect serial4 as DCE from BBB to your PC with > a straight cable, and pretend your PC is the CNC. See if you can open a > terminal on the PC and BBB and see data both ways. If so then it should > work on the CNC just by moving the cable over. This assumes the CNC doesn't > need some specific flow control or handshake. You might be able to disable > that from the CNC side so all it needs is TX and RX. > > Aren't serial ports wonderfully confusing? > > At this moment I have a headache from working on code and hardware (not on > BBB, we are using a Teensy ARM Cortex M4 this time) talking to a custom > RS422-sort-of serial connection so I feel your pain. > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/Z1s_NwXYNrw/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CAC32br%2BK65pihWC4ZwDfCB8xgwNxe1pAZ2oj_RWME%3DL3KVPX%3DQ%40mail.gmail.com > <https://groups.google.com/d/msgid/beagleboard/CAC32br%2BK65pihWC4ZwDfCB8xgwNxe1pAZ2oj_RWME%3DL3KVPX%3DQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAEh-rEHWeGt%3DNzY%3DRjGeZ447L%3DxO9_06wnqFAW%3D%2BrBKnrHDogg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
