Posted 20 Apr 2017 Unable to communicate to SLC5/04 DF1 port using null modem cable, even after resetting processor to factory defaults by shorting the VBB & GND pins or by shorting the capacitor. I can connect to the processor and download a program via the 1784-U2DHP adapter, but still can't connect to the DF1 port. To prove my cable and USB to serial works, I move it to another SLC PLC and it communicates properly. I spoke with Rockwell support at length and they say that the port is bad and there is nothing else that can be done. Does anyone know of any other steps that I could take to get the DF1 port to work? Thanks. Share this post Link to post Share on other sites
Posted 21 Apr 2017 Allen-Bradley's DF1 cable appears to be a typical serial cable with the exception of the gender at one end. Typical serial cable is M-F DB-9; Allen-Bradley's DF1 cable is M-M DB-9. There is a pinout further down this post with image and PDF link. http://www.plctalk.net/qanda/showthread.php?t=30087&page=2 The SLC-5/04 DB-9 port (Channel 0) is configurable for DH-485, DF1, or ASCII. Do you know for sure that the CH0 port is configured as DF1? I cannot say for sure if a SLC-5/04 factory default restore puts the ports back to original settings. Have you tried to make your own DF1 cable? (2) Phoenix Contact DB-9 male field wireable connectors and a section of quality RS-232 wire. Or hack up a pair of serial cables, soldered up with good noise immunity. Share this post Link to post Share on other sites