I have used USR56K with an SLC5/03 and configured it using MrPLC's article :
http://www.mrplc.com/kb/index.php?page=ind...ex_v2&id=9&c=11

Now I cannot get the EZ220 to talk to the SLC anymnore ...

I need to get this modem AND the HMI to talk to the darn AB PLC.

Any hints?

Was the EZ220 connected to CH. 0 (serial port) on the SLC before you connected the modem? If the EZ220 was configured for AB DF1 comms, and you changed CH. 0 protocol control to Full Duplex Modem, then the EZ220 probably won't like that. Any way to connect the EZ to the DH-485 port?

The problem happens when I configure the protocol to be Full duplex modem.

All else is OK but what is this f... d... modem protocol?

"Full Duplex Modem" means "DF1 Full Duplex with RTS/CTS Hardware Handshaking".



Do you want all three devices to communicate simultaneously ?

Full Duplex DF1 protocol is point-to-point ONLY. If you have three devices, they aren't going to be able to use Full Duplex. You can't mix, for example, DH-485 protocol and DF1 Full Duplex protocol.

There are devices, like TomanTron's MUXIPort, that allow several DF1 Full Duplex devices to communicate. A-B is coming out with a port splitter this summer.


Do you want the modem OR the EZ220 to communicate with the SLC, one at a time ?

If the modem is using hardware handshaking, and the EZ220 cannot use hardware handshaking, then I don't think you are going to be able to resolve that conflict. You can't just enable and disable hardware handshaking on the port. You might be able to jumper the hardware handshaking pins in the cable that connects to the EZ220, and leave the port set for hardware handshaking so it works with the modem.