Can I use the RTS/CTS Flow Control setting in the Link Wizard to talk from DirectSOFT to DL PLC?
No. The reason is that the PLC port does not listen to its CTS line for incoming data. It only uses the Flow Control RTS/CTS lines when it wants to send data. So, if you choose RTS/CTS Flow Control in DirectSOFT, then when DirectSOFT wants to talk to the PLC, it will set the RTS line, which, if wired correctly, would tell the PLC it wants to send data. However, because the PLC is not listening to that line, it would never send DirectSOFT the CTS, so DirectSOFT would time out.