Comm Port Dead on L35E

[smichalo 0]

Hi All I have an 1769-L35E compactlogix controller with on board ethernet and serial. I communicate through ethernet just fine but this morining I wanted to program with the comm port. ( ethernet cable was in my tool kit in the car, got lazy... ) So I used my rockwell supplied serial cable and adapter ( Part no. 1756CP/3A on the cable and A0101704061 on the USB Serial convertor ) and when I went to communicate I got the Unknown device and big red "X" in rslinx. My first thought was the EDS file but this is not the case. I flashed the firmware on the controller to V17 through the comm port so it did work at one time. But I did read in another post that upgrading the firmware through the comm port might render the comm port useless. The comm port LED is totaly dead so I am thinking this is the case. Is this possible? and if this is the case is the only fix to change the processor? I'm just curious I could live without the comm port. I just got off my booty and went to get the ethernet cable. Thanks Steve

[Ken Roach 194]

I've never heard of a firmware upgrade by any method damaging or rendering the serial port nonfunctional and not interfering with the firmware load. It's more likely that the port got inadvertently changed to User Mode, or that your USB/RS232 interface changed COM port assignments without your knowledge. The RS232 port LED on any A-B controller only flashes when the port transmits. You could check the port by putting a MSG or ASCII Write instruction in your program and see if the serial port flashes.

[slcman 9]

You may check Serialport config of your plc while online thru ethernet port. As Ken say, you will be sure you're got DF1 protocol. If DF1 are used, you may check witch port of you laptop the AB USB adapter use (in system -> hardware config). I never had to work with AB USB serial adapter but with other USB adapter like 1747-UIC the COM port could change if I connect adapter in different USB port of my pc. Wish it's help