1-81.2.2 Communication FunctionsMEWTOCOL Communication FunctionThere are two MEWTOCOL communication functions: a computer link function and a data transferfunction.Computer link function: MEWTOCOL-COM (ASCII communication)- Computer link communications can be realized by transmitting MEWTOCOL-COM data format from thecomputer to the programmable controller.- The computer can read from and write to the programmable controller’s I/O and registers.- The maximum message length for one frame is 2k bytes.- Using programming tools such as the FPWIN GR, remote programming and monitoring can be donethrough a LAN circuit.Data transfer function: MEWTOCOL-DAT (binary communication)- Execution of the data transfer instruction “F145 (SEND)/P145 (PSEND) and F!46 (RECV)/P146(PRECV)” by a programmable controller program allows data transfer communications betweenprogrammable controllers and between a programmable controller and a computer. Datacommunication whereby the computer transfers the MEWTOCOL-DAT data format to theprogrammable controller is also possible.- The computer can read from and write to the programmable controller’s I/O and registers. Theprogrammable controller can read from and write to the computer’s virtual I/O and virtual registers.A programmable controller can read from and write to the I/O and registers of another programmablecontroller partner node.- The maximum amount of data that can be transferred by execution of one data transfer instruction is1020 words.Key Point:- The programmable controller specifies the IP address and MEWTOCOL station number (1 to 64), andopens a connection with its communication partner’s node using MEWTOCOL communication mode.- When the programmable controller receives the MEWTOCOL command message, it returns aresponse message automatically, so there is no need to describe a program to generate a response.- With the MEWTOCOL communications function and the transparent communications function, you cansimultaneously use a maximum of eight connections with one ET-LAN unit.The computer link function and data transfer function can be executed simultaneously using oneconnection.- Hierarchical communication via other MEWNET networks is also possible.- When using the data transfer function, we recommend that you use TCP/IP to guaranteecommunications reliability.- When carrying out remote programming and monitoring, the ET-LAN unit settings should be set to theMEWTOCOL communication mode and to TCP/IP communication, and the processing of the variousflags should be executed through a shared memory handshake.
