MicroLogix 1500 DCOMM issue (Jhoan Rojas)

The following question was appended to a five-year-old thread by a new Forum member, so I'm re-posting his question to a new thread:

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Hello, I have tried to connect a Panelview 550 with dh485 protocol(rs232 port) and Micrologix 1500 LSP B.

It was easy programming the panelview, and the PLC, but I had to change the configuration of channel 0 (PLC). So I changed it from DF1 to dh-485, like this: "Change the serial port Channel 0 from DF1 Full Duplex to DH485 while online. The software will warn you that you will lose communications; go ahead and accept the change."

Then, I connected the plc with the panelview and they worked perfectly.

But after a few minutes I tried to change the configuration of Channel 0 to DF1 again, pusshing the "COMS" button. I did it, but I made all this procedure again and I can't use the RS232 pc serial port. I have probed it in several different ways, and I think that this port is damaged. So I don't want to use another RS-232 port to change from DF1 to DH-485. I'm afraid.
I hope you can help me, thank you.

Jhoan
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When you use the "DCOMM" button on a MicroLogix 1500 or MicroLogix 1200 controller, make sure you hold it long enough for the DCOMM LED to turn on steady green.

When the DCOMM LED is on steady, the Channel 0 serial port (the Mini-DIN8 round port) is set for DF1 Full Duplex protocol at 19200 baud, 8/N/1 framing, CRC error checking. These are the default settings for a DF1 Full Duplex driver in RSLinx Classic.

The DCOMM feature does not affect the Channel 1 serial port on the MicroLogix 1500 1764-LRP controller.

If you have previously been using the "1747-PIC/AIC+" driver, you may need to delete all instances of that driver and reboot your computer before you can successfully use a DF1 Full Duplex driver again.

Unless you used a home-made cable and accidentally connected Pin 1 to a data pin (it's +24V DC) then it is unlikely that your PC's serial port is actually damaged.

It could be a home-made cable problem. I verified the programming cable and it worked OK in other pc, many times. Many thanks for your answer.

Jhoan