How to talk to PLC over Ethernet

[JodyOno]

I'm writing a Windows application to talk to several FMD-88's over Ethernet, but it is not clear from the user's guide what I should be sending to each unit.  Do I send commands as if I'm sending from another PLC?  This  doesn't seem to work.  I've used Wireshark to look at the network conversation from i-TRILOGI to an FMD-88 and the protocol looks different from what is in the user's guide.  Any help would be greatly appreciated.

[support]

There are three ways a Windows application can interact with the PLC over Ethernet:

1) Login to F-server using TCP connection. This is the most comprehsive method since you can access to all internal variables and memory using the host link command protocols.

A sample visual basic program together with a DLL to aid login using encrypted password is included. Please visit URL:

http://www.tri-plc.com/appnotes/AppnoteMain.htm

2) Connect to the PLC's Modbus/TCP server at port 502 and then send Modbus/TCP commands to the server and receive Modbus/TCP response. This allows you to read/write to most of the 16-bit variables inside the PLC.

3) Connect to the PLC's webserver using the HTTP protocol and web query method. Like option (1) You can use all host link commands to access any variables inside the PLC but the performance is much slower than the direct TCP connection. The URL to access the host link command is simply:

IPaddress: port/HOSTLINK/[command]

E.g.

http://192.168.1.5:9080/HOSTLINK/RI00