Panasonic FP2 ET-LAN, Technical Manual

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1.2.2 Communication Functions
MEWTOCOL Communication Function
There are two MEWTOCOL communication functions: a computer link function and a data transfer
function.
Computer link function: MEWTOCOL-COM (ASCII communication)
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Computer link communications can be realized by transmitting MEWTOCOL-COM data format from the
computer to the programmable controller.
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The computer can read from and write to the programmable controller’s I/O and registers.
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The maximum message length for one frame is 2k bytes.
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Using programming tools such as the FPWIN GR, remote programming and monitoring can be done
through a LAN circuit.
Data transfer function: MEWTOCOL-DAT (binary communication)
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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 between
programmable controllers and between a programmable controller and a computer. Data
communication whereby the computer transfers the MEWTOCOL-DAT data format to the
programmable controller is also possible.
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The computer can read from and write to the programmable controller’s I/O and registers. The
programmable 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 programmable
controller partner node.
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The maximum amount of data that can be transferred by execution of one data transfer instruction is
1020 words.
Key Point:
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The programmable controller specifies the IP address and MEWTOCOL station number (1 to 64), and
opens a connection with its communication partner’s node using MEWTOCOL communication mode.
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When the programmable controller receives the MEWTOCOL command message, it returns a
response message automatically, so there is no need to describe a program to generate a response.
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With the MEWTOCOL communications function and the transparent communications function, you can
simultaneously use a maximum of eight connections with one ET-LAN unit.
The computer link function and data transfer function can be executed simultaneously using one
connection.
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Hierarchical communication via other MEWNET networks is also possible.
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When using the data transfer function, we recommend that you use TCP/IP to guarantee
communications reliability.
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When carrying out remote programming and monitoring, the ET-LAN unit settings should be set to the
MEWTOCOL communication mode and to TCP/IP communication, and the processing of the various
flags should be executed through a shared memory handshake.