Siemens OP277 to AB SLC504 via DF1 and RS232/RS422 converter.

[JesperMP]

Hi all.

I am having trouble getting a Siemens OP277 and an AB SLC504 to talk to each other via DF1.
The older panels OP25/OP27/OP270 had an RS232 port and always worked OK.
Now the newer panel OP277 only has an RS422/RS485 port, and there must be a converter to allow it to connect via RS232 to the SLC504's Ch0 port. To this end I have installed the adapter 6AV6671-XE00-0AX0.

What works:
Downloading from the PC (WinCC Flexible) to the OP277 via the adapter and a null-modem cable.
Downloading from the PC (RSLogix) to the SLC504 via the same null-modem cable.
Converting the OP277 program to a PC RT and connecting to the SLC504 via the same null-modem cable also works OK.

What does not work:
Connecting the OP277 and the SLC504 via the same adapter and same null-modem cable.

The online settings have been checked. The program for the OP277 is a converted OP25 program that has worked before.
The dipswitches on the rear of the OP277 are set to RS422/RS485.
I have rebooted both OP277 and SLC504.
All to no avail.

 

[JesperMP]

Solved !! Yahuuu .

It turns out, if you have the serial port on the panel enabled for transfer of the project - it disables the port to be used for the DF1 protocol.

Thanks to all that helped in the process !