Panasonic FP2 ET-LAN User manual

PROGRAMMABLE CONTROLLER
[Applicable Model]
・ FP2-ET1 (Model No. AFP2790) (Discontinued product)
・ FP2-ET2 (Model No. AFP27901)
FP2 ET-LAN Unit
Technical Manual
ARCT1F322E-7
2013.12 panasonic.net/id/pidsx/global

Safety Precautions
Observe the following notices to ensure personal safety or to prevent accidents.
To ensure that you use this product correctly, read this User’s Manual thoroughly before use.
Make sure that you fully understand the product and information on safety.
This manual uses two safety flags to indicate different levels of danger.
WARNING
If critical situations that could lead to user’s death or serious injury is assumed by
mishandling of the product.
-Always take precautions to ensure the overall safety of your system, so that the whole
system remains safe in the event of failure of this product or other external factor.
-Do not use this product in areas with inflammable gas. It could lead to an explosion.
-Exposing this product to excessive heat or open flames could cause damage to the lithium
battery or other electronic parts.
CAUTION
If critical situations that could lead to user’s injury or only property damage is
assumed by mishandling of the product.
-To prevent excessive exothermic heat or smoke generation, use this product at the values
less than the maximum of the characteristics and performance that are assured in these
specifications.
-Do not dismantle or remodel the product. It could cause excessive exothermic heat or smoke
generation.
-Do not touch the terminal while turning on electricity. It could lead to an electric shock.
-Use the external devices to function the emergency stop and interlock circuit.
-Connect the wires or connectors securely.
The loose connection could cause excessive exothermic heat or smoke generation.
-Do not allow foreign matters such as liquid, flammable materials, metals to go into the inside
of the product. It could cause excessive exothermic heat or smoke generation.
-Do not undertake construction (such as connection and disconnection) while the power
supply is on. It could lead to an electric shock.
Copyright / Trademarks
-This manual and its contents are copyrighted.
-You may not copy this manual, in whole or part, without written consent of Panasonic
Industrial Devices SUNX Co., Ltd.
-Windows is a registered trademark of Microsoft Corporation in the United States and other
countries.
-Ethernet is a registered trademark of Fuji Zerox Co., Ltd. And XeroxCorp.
-All other company names and product names are trademarks or registered trademarks of
their respective owners. PLC_ORG_ET

i
Table of Contents
Compatibility with the FP3
Difference between AFP2790 and AFP27901
1. Unit Functions and Restrictions............................................................ 1-1
1.1 Features and Structure of ET-LAN Unit.........................................................................1-2
1.1.1 Features......................................................................................................................1-2
1.1.2 Unit Type.....................................................................................................................1-3
1.1.3 Structure of Network ...................................................................................................1-3
1.1.4 Connecting to a Network.............................................................................................1-4
1.1.5 Connections Between Networks.................................................................................1-6
1.2 Overview of ET-LAN Unit Functions..............................................................................1-7
1.2.1 Function Model............................................................................................................1-7
1.2.2 Communication Functions ..........................................................................................1-8
1.2.3 Self Diagnosis Functions ..........................................................................................1-10
1.3 Restrictions on Units Combination .............................................................................1-11
1.3.1 Restrictions on Current Consumption.......................................................................1-11
1.3.2 Restrictions on Installation Position..........................................................................1-11
1.3.3 Restrictions on Number of Units that can be Installed..............................................1-12
1.4 Restrictions on Unit Version and Functions ..............................................................1-12
1.4.1 Functions of ET-LAN Unit and Applicable Versions .................................................1-12
1.4.2 Precautions when using the e-mail function .............................................................1-12
1.5 Unit Version and Communication Setting Method.....................................................1-13
1.5.1 Configurator ET.........................................................................................................1-13
1.6 Restrictions Relating to Communication Conditions and Functions ......................1-13
1.6.1 Precautions When Using the FP2 CPU Unit.............................................................1-13
2. Names and Functions of Parts .............................................................. 2-1
2.1 Names and Functions of Parts.......................................................................................2-2
2.1.1 Names and Functions of Parts....................................................................................2-2
2.1.2 Operating Status LEDs ...............................................................................................2-3
2.1.3 Mode Setting Switch ...................................................................................................2-3
2.2 Connector Pin Layout .....................................................................................................2-4
2.2.1 10BASE5(AUI) Connector (with D-SUB 15 pins retainer) ..........................................2-4
2.2.2 100BASE-TX/10BASE-T Connector (RJ45)...............................................................2-4
2.2.3 External Power Supply Terminal for 10BASE5 (12 V DC)..........................................2-4
3. Connection for LAN Cable ..................................................................... 3-1
3.1 Precautions Concerning Installation.............................................................................3-2

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3.2 Connection for LAN Cable..............................................................................................3-4
3.2.1 100BASE-TX and 10BASE-T Connections.................................................................3-4
3.2.2 10BASE5 (AUI) Connections......................................................................................3-5
3.3 Test Mode.........................................................................................................................3-6
3.3.1 Types and Contents of Test Modes............................................................................3-6
3.3.2 Running Test Modes...................................................................................................3-7
4. Confirming the Design Contents...........................................................4-1
4.1 Address Confirmation.....................................................................................................4-2
4.1.1 IP Address Confirmation.............................................................................................4-2
4.1.2 MEWTOCOL Station Number Confirmation ...............................................................4-2
4.2 I/O Allocations..................................................................................................................4-3
4.2.1 Confirmation of I/O Allocations ...................................................................................4-3
4.2.2 Confirmation of Route Numbers .................................................................................4-4
4.3 Confirmation of the Contents of the Shared Memory..................................................4-5
4.3.1 Configuration of the Shared Memory..........................................................................4-5
4.3.2 The Roles Played by the Various Areas.....................................................................4-6
4.4 Handshake Method..........................................................................................................4-8
4.4.1 Handshake Method.....................................................................................................4-8
4.4.2 Using the I/O for the Handshake.................................................................................4-9
4.4.3 Using the Shared Memory for the Handshake..........................................................4-10
5. Initialization Processing and Termination Processing........................5-1
5.1 Initialization/Termination Processing............................................................................5-2
5.1.1 What is Initializaiton Processing? ...............................................................................5-2
5.2 Processing Procedures...................................................................................................5-4
5.2.1 An Overview of the Initialization Processing Procedure.............................................5-4
5.2.2 An Overview of the Termination Processing Procedure.............................................5-5
5.2.3 Writing Data to the Initialization Information Setting Area ..........................................5-6
5.2.4 Writing Data to the Routing Information Setting Area...............................................5-12
5.3 Reading Initialization Information................................................................................5-17
5.4 Sample Program ............................................................................................................5-19
6. Open Processing and Close Processing..............................................6-1
6.1 Open/Close Processing ..................................................................................................6-2
6.1.1 What is Open Processing?..........................................................................................6-2
6.1.2 Types of Open Processing..........................................................................................6-4
6.2 Processing Procedures...................................................................................................6-7
6.2.1 An Overview of the Open Processing Procedure .......................................................6-7

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6.2.2 An Overview of the Close Processing Procedure.......................................................6-8
6.2.3 Writing Data to the Connection Information Setting Area...........................................6-9
6.3 Reading Connection Information.................................................................................6-12
7. Computer Link Function ........................................................................ 7-1
7.1 An Overview of the Computer Link Function ...............................................................7-2
7.1.1 What is the Computer Link Function?.........................................................................7-2
7.1.2 Commands and Functions Available for Use..............................................................7-3
7.2 Computer Link Procedure ..............................................................................................7-5
7.3 Settings on the PLC Side................................................................................................7-6
7.3.1 Connection Information Settings.................................................................................7-6
7.3.2 Writing to the Shared Memory....................................................................................7-8
7.3.3 Sample Program.........................................................................................................7-9
7.4 Command Communication on the Computer Side ....................................................7-11
7.4.1 Communication Data Format (1)...............................................................................7-11
7.4.2 Communication Data Format (2)...............................................................................7-14
8. Data Transfer Function........................................................................... 8-1
8.1 An Overview of the Data Transfer Function .................................................................8-2
8.1.1 What is the Data Transfer Function?..........................................................................8-2
8.1.2 Commands and Functions that can be Used..............................................................8-3
8.2 Data Transfer Procedure.................................................................................................8-4
8.3 Settings on the PLC Side................................................................................................8-5
8.3.1 Connection Information Settings.................................................................................8-5
8.3.2 Writing to the Shared Memory....................................................................................8-7
8.3.3 Sample Program.........................................................................................................8-8
8.4 Command Communication on the Computer Side....................................................8-10
8.4.1 Communication Data Format (1)...............................................................................8-10
8.4.2 Communication Data Format (2)...............................................................................8-13
8.4.3 Communication Data Format (3)...............................................................................8-16
9. Transparent Communication Function................................................. 9-1
9.1 An Overview of the Transparent Communication Function........................................9-2
9.1.1 What is the Transparent Communication Function?...................................................9-2
9.2 Transparent Communication Procedures.....................................................................9-3
9.3 Settings on the PLC Side................................................................................................9-4
9.3.1 Connection Information Settings.................................................................................9-4
9.3.2 Writing to the Shared Memory....................................................................................9-5

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9.4 Communication Processing for Transparent Communication...................................9-6
9.4.1 Connection Processing Procedure .............................................................................9-6
9.4.2 Procedure for Transmission Processing.....................................................................9-8
9.4.3 Procedure for Reception Processing ........................................................................9-10
9.4.4 Handshake Signal and Data Area.............................................................................9-13
9.5 Sample Program ............................................................................................................9-16
9.5.1 Sample Program <Initialization to Open>.................................................................9-16
9.5.2 Sample Program <Transmission Processing and Reception Processing> ..............9-18
9.5.3 Sample Program <Reception to Transmission>.......................................................9-21
10. Auto Connection.................................................................................10-1
10.1 Auto Connection Function..........................................................................................10-2
10.1.1 Reading Auto Connection Status Information.........................................................10-5
10.1.2 Auto Initialization Processing..................................................................................10-6
10.1.3 Auto Open Processing............................................................................................10-7
10.1.4 Auto Connection Information Settings ....................................................................10-8
10.1.5 Reading Auto Connection Information....................................................................10-9
10.1.6 Sample Program ...................................................................................................10-11
10.2 System Connection ...................................................................................................10-23
10.2.1 Initialization processing in the system connection................................................10-23
10.2.2 Open processing in the system connection..........................................................10-23
10.2.3 System Connection Information Setting................................................................10-24
10.2.4 Reading system connection information settings .................................................10-26
11. E-mail Function...................................................................................11-1
11.1 Outline of E-mail Function..........................................................................................11-2
11.1.1 E-mail Function Specification..................................................................................11-2
11.2 Precautions When Using the E-mail Function..........................................................11-3
11.3 Operation Environment...............................................................................................11-5
11.4 Sending/Receiving E-mails Using E-mail Function .................................................11-6
11.5 E-mail Function............................................................................................................11-7
11.6 Security in Receiving E-mails ..................................................................................11-10
11.7 Outline of Request E-mail Function.........................................................................11-12
11.7.1 Request Mail Format.............................................................................................11-13
11.8 Sending E-mail Using the Ladder Program ............................................................11-15
11.8.1 E-mail Send Processing Using the Ladder Program ............................................11-15
11.8.2 Ladder Send E-mail Settings ................................................................................11-17
11.8.3 Sample Program (for sending e-mails).................................................................11-18
11.9 Receiving E-mails using the Ladder Program........................................................11-19

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11.9.1 Sample Program (for receiving e-mails) ...............................................................11-21
11.10 E-mail Error Log and E-mail Log Functions .........................................................11-22
11.10.1 What are the e-mail error logs and e-mail log functions.....................................11-22
11.10.2 Reading E-mail Error Log ...................................................................................11-23
11.10.3 Reading E-mail logs............................................................................................11-25
11.10.4 E-mail Status Area..............................................................................................11-27
11.10.5 Sample Program.................................................................................................11-28
11.11 Troubleshooting Flowchart ....................................................................................11-31
12. Error Log Function ............................................................................. 12-1
12.1 Configuration of the Error Log Area..........................................................................12-2
12.1.1 What is the Error Log Function?.............................................................................12-2
12.1.2 Contents of Error Log Area.....................................................................................12-4
12.2 Reading the Error Log.................................................................................................12-5
12.2.1 Procedure for Reading the Error Log......................................................................12-5
12.2.2 Sample Program.....................................................................................................12-6
12.3 Error Code Contents ...................................................................................................12-7
12.3.1 Access Error............................................................................................................12-7
12.3.2 System Error.........................................................................................................12-12
12.3.3 Warning Error........................................................................................................12-12
12.3.4 Recovery Possible Error .......................................................................................12-13
12.3.5 E-mail Send Error..................................................................................................12-15
12.3.6 E-mail Receive Error transmission........................................................................12-16
12.3.7 MEWTOCOL Error................................................................................................12-17
12.3.8 Hardware Error......................................................................................................12-17
12.3.9 Auto Connection Error ..........................................................................................12-18
13. Troubleshooting.................................................................................. 13-1
13.1 Operation If an Error Occurs......................................................................................13-2
13.1.1 Operation If the ALARM LED on the ET-LAN Unit Lights.......................................13-2
13.1.2 Operation If the “E1” or “E2” LED on the ET-LAN Unit Lights or Flashes ..............13-3
13.2 What to Do If an Error Occurs....................................................................................13-4
13.2.1 If the Alarm "ALM" LED Lights on the ET-LAN Unit................................................13-4
13.2.2 If the "E1" LED on the ET-LAN Unit Lights or Flahses...........................................13-4
13.2.3 If the “E2” LED on the ET-LAN Unit Lights or Flashes ...........................................13-4
13.2.4 Troubleshooting Flowchart......................................................................................13-6
13.3 Reset Function.............................................................................................................13-8
13.3.1 What is the Reset Function?...................................................................................13-8
13.3.2 No Communication Notification Function................................................................13-8
13.3.3 Procedure of Reset Function..................................................................................13-9
13.3.4 Reset Function Sample Program..........................................................................13-10

vi
14. MEWTOCOL Communication Procedure..........................................14-1
14.1 MEWTOCOL-COM (Computer Link)...........................................................................14-2
14.1.1 Overview of MEWTOCOL-COM .............................................................................14-2
14.1.2 Single Frames and Multiple Frames .......................................................................14-6
14.1.3 List of MEWTOCOL-COM Commands ...................................................................14-8
14.2 MEWTOCOL-DAT (Data Transfer)............................................................................14-25
14.2.1 Overview of MEWTOCOL-DAT ............................................................................14-25
14.2.2 List of MEWTOCOL-DAT Commands ..................................................................14-27
14.3 MEWTOCOL Error Codes..........................................................................................14-31
14.3.1 Table of Error Code...............................................................................................14-31
15. Specifications......................................................................................15-1
15.1 Tables of Performance Specifications ......................................................................15-2
15.1.1 General Specifications............................................................................................15-2
15.1.2 Performance Specifications ....................................................................................15-2
15.1.3 Communication Specifications................................................................................15-3
15.2 I/O Allocation................................................................................................................15-4
15.3 Table of Shared Memory.............................................................................................15-5
15.4 Table of Related Relays, Registers and Instructions.............................................15-25
15.4.1 System Register....................................................................................................15-25
15.4.2 Special Internal Relay...........................................................................................15-26
15.4.3 System Register....................................................................................................15-27
15.5 Minimum Transmission Delay Time ........................................................................15-28
15.6 ASCII Codes ...............................................................................................................15-30
15.7 Dimensions ................................................................................................................15-31
16. Sample Program .................................................................................16-1
16.1 Sample Program ..........................................................................................................16-2
16.1.1 An Overview of the Sample Program......................................................................16-2
16.1.2 Workstation Sample Program.................................................................................16-3
16.1.3 Communication Setting Program on PLC Side.......................................................16-8

vii
Compatibility with the FP3
Differences with the FP3 ET-LAN unit
The main differences between the specifications and operation of the FP2 ET-LAN unit and the FP3 ET-
LAN unit are given in the table below. Refer to the reference page numbers given for each item for
details regarding specifications and operation.
Item FP2 ET-LAN unit FP3 ET-LAN unit
Communication
interface
(See page 1-4.)
100BASE-TX, 10BASE-T, and 10BASE5 10BASE5
Mode setting
switch
(See page 2-3.)
1. 100BASE-TX/10BASE-T and 10BASE5 switch
2. Reserved
3. Normal mode/test mode switch
4. Test mode operation selection
1. Test mode operation selection
2. Handshake mode selection
3. ONLINE/OFFLINE switch
4. Normal mode/test mode switch
Mounting
position/qty.
limits
(See page 1-11
and 1-12.)
The following quantities can be inserted in any of
the master backplane slots (including Multi-wiring
link unit MEWNET-W2 mode)
With the FP2 CPU unit: 3 units
With the FP2SH CPU unit: 8 units
The following quantities can be inserted
in any of the master backplane slots
(including MEWNET-H link unit)
FP3/FP10SH CPU unit: 3 units
Handshaking
(See page 4-8.) I/O handshaking and shared-memory handshaking can be used simultaneously.
The mode setting switch is used to switch
between I/O handshaking and shared
memory handshaking.
Handshake
signals
(See pages 4-9
to 4-12.)
I/O handshaking signals
Deleted: I/O handshake mode flag (XE)
Shared memory handshake signal
Deleted: I/O handshake mode flag
(bank 0: 360H bit E)
Added: Expansion complete signal area 2
(bank 0: 366H)
-
Shared memory
(See page 15-5.)
Connection data notification block
(bank 0: 2E0H to 35FH)
Added: Receive processing complete code
(offset address A)
Receive unnotified data size
(offset address B)
Receive unnotified data size copy
(offset address C)
-
Test mode
(See page 3-6.)
Test items
1. Mode setting switch test
2. LED test
3. ROM test
4. RAM test
5. Shared memory test
6. Timer test
7. Internal loopback test
8. External loopback test
Added: Mode setting switch test
Deleted: EEPROM checksum test
Modified: LED display during testing and error
Test items
1. LED test
2. ROM test
3. RAM test
4. Shared memory test
5. EEPROM checksum test
6. Timer test
7. Internal loopback test
8. External loopback test
Error log
(See page 12-7.)
Error codes added
8036H: MEWTOCOL transmission error
Error codes deleted
8006H: OFFLINE error
8009H: Mode change error
8019H: Forced close error
B001H/B002H: ONLINE/OFFLINE switching error
during operation
-
Ladder program Ladder programs created using the FP3 can be
used without modification.
-

viii
Difference between AFP2790 and AFP27901
Available communication functions vary between AFP2790 and AFP27901.
100BASE-TX
10BASE-T
10BASE5
AFP2790
Available
Available
Available
AFP27901
Available
Available
Not available
Note) AFP27901 has no 10BASE5 connector.
Other functions are common.

Chapter 1
Unit Functions and Restrictions

1-2
1.1 Features and Structure of ET-LAN Unit
1.1.1 Features
The FP2 ET-LAN unit is an Ethernet (100BASE-TX, 10BASE-T or 10BASE5) connection interface for
TCP/IP and UDP/IP for the FP2 and FP2SH series programmable controllers.
Supports both TCP/IP and UDP/IP
The ET-LAN supports both the TCP/IP and UDP/IP protocols, enabling communication with a broad
range of computers and other devices in a network.
Simultaneous communication possible among up to eight connected connections
Communication can be carried out among up to eight connections connected to the network using only a
single unit. This enables connection to multiple partner nodes.
Three types of communication interfaces supported
Three types of Ethernet communication interfaces are supported (Usable interfaces vary according to
the models): 100BASE-TX, 10BASE-T, and 10BASE5. Any one of these interfaces may be used.
Automatic switching is possible between 100BASE-TX and 10BASE-T using an auto-negotiation function,
while a switch can be used to switch between 100BASE-TX/10BASE-T and 10BASE5.
100BASE-TX
10BASE-T
10BASE5
AFP2790 Available Available Available
AFP27901
Available
Available
Not available
Easy-to-use MEWTOCOL communication and general-purpose transparent communication
supported
The MEWTOCOL communication function (computer linking and data transmission) that enables
communication between personal computers, workstations, and FP series programmable controllers is
supported, as well as the transparent communication function that enables communication between
general-purpose devices such as computers.
Easy communication set-up
Communication settings can be easily performed using the setting tool (Configurator ET).
Changing the mode setting switches enables the communication setting to be performed by a ladder
program.
Using the system connection enables easy connections with devices such as a programming tool
(FPWIN GR).

1-3
E-mail send and receive functions (for a standard equipment)
Sending e-mails
- Errors occurred in the programmable controller can be notified via e-mail.
- E-mails can be sent at the specified time.
- The devices of programmable controller are monitored and e-mails can be sent when the designated
conditions are satisfied.
Receiving e-mails
- Receiving an e-mail described in a specific format enables to notify the status of the programmable
controller via e-mail.
A broad range of self-diagnosis functions
- A function that checks the hardware and the communication status during operation.
- A function that checks the hardware and the communication status when the test mode is accessed.
- An error log function that records the results of various checks.
1.1.2 Unit Type
Name
Part No.
Model No.
FP2 ET-LAN unit FP2-ET1 AFP2790
FP2 ET-LAN2 unit
FP2-ET2
AFP27901
Note) No accessories such as connectors or cables are included.
1.1.3 Structure of Network
Communication functions of ET-LAN unit
Using the ET-LAN unit to connect to an Ethernet (100BASE-TX, 10BASE-T, or 10BASE5) enables (1)
computer link function, (2) data transfer function, and (3) transparent communication function to be
carried out with other programmable controllers and computers connected to the network.
Combined use with a conventional MEWNET
The ET-LAN unit can be used in combination with another network unit such as the MEWNET-W/W2.
This makes it possible to connect an existing FA network to an Ethernet LAN, using MEWNET.

1-4
1.1.4 Connecting to a Network
AFP2790
100BASE-TX/10BASE-T
10BASE5 (AUI)
AFP27901

1-5
Communication specifications
Item
100BASE-TX Note1)
10BASE-T Note1)
10BASE5
Target model AFP2790
AFP27901
AFP2790
AFP27901
AFP2790
Data transfer 100M bits/s 10M bit/s 10M bit/s
Transfer method
Base band
Base band
Base band
Max. segment length 100 m Note2) 100 m Note2) 500 m
Max. distance
between nodes
205 m (2 segments) 500 m (5 segments) 2500 m (5 segments)
Communication cable
for connection UTP (Category 5) UTP (Category 3, 4
and 5) Transceiver cable
Max. transceiver cable
length
- - 50 m Note3)
Max. number of nodes - - 100 nodes/segment
Node spacing
-
-
Integer multiples of 2.5 m
Note1) Switching between 100BASE-TX and 10BASE-T is done automatically by auto negotiation
function.
Note2) The standards cite 10 m as the maximum, but noise resistance measures such as attaching a
ferrite core may be necessary in some cases, depending on the usage environment. Also, if the
hub is positioned close to a control board, we recommend using it at a distance of 10 m or less.
Note3) The standards cite 50 m as the maximum, but noise resistance measures such as attaching a
ferrite core may be necessary in some cases, depending on the usage environment. Also, if the
transceiver is positioned close to a control board, we recommend using it at a distance of 5 m or
less.

1-6
1.1.5 Connections Between Networks
With an Ethernet, communication is possible not only between the home network and a node, but also
between the nodes of other networks, using routers.
As shown in the illustration above, communication with nodes of other networks is classified as follows:
- The router is registered in advance, and communication is carried out between partner nodes of
adjacent networks (other networks 1, 2, 3, etc. in the above illustration)
- Communication is carried out with the partner nodes of networks other than those shown above (other
networks A, B, C, etc. in the above illustration)
Key Point:
When using the ET-LAN unit to carry out communication with partner nodes on another network, the
router used by the ET-LAN unit should be registered.
(1) Up to five routers can be registered for the source network, enabling communication with any of the
nodes on another adjacent network.
(See other networks 1, 2, 3 etc. in the left illustration.)
(2) Only a single default router can be registered, and communication carried out with any desired node
on any network other than those covered by (1), through the default router. (See other networks A,
B, C, etc. in the left illustration.)
The router may be one of the five routers specified at (1), or may be a different router.

1-7
1.2 Overview of ET-LAN Unit Functions
1.2.1 Function Model
The functions of the ET-LAN unit are shown in the diagram below.
I/O and shared memory are used for the interface to the user program (CPU unit).
A maximum of eight simultaneous connections are possible for each of the computer link, data transfer,
and transparent communication functions.
The layers beneath the transport layer of the ET-LAN unit provide the following communication services.
TCP (Transmission Control Protocol):
TCP is a connection-based communication method which provides the virtual circuit. In the TCP
communication method, since communication services including re-transmission, sequence and flow
control for the communication data are provided, high communication reliability is guaranteed at the
protocol level.
UDP (User Datagram Protocol):
UDP is a connectionless communication method which provides only data communication in IP units. In
the UDP communication method, since no re-transmission, sequence, or flow control for the
communication data is provided, support at the application level is required to guarantee communication
reliability.
IP (Internet Protocol):
IP is used to transmit data in units of datagrams to partner node specified by an IP address. It provides
function such as the dividing and reassembling of communication data and communication services
between networks via a router.
ICMP (Internet Control Message Protocol):
ICMP is used to transmit the error message in the IP. The ET-LAN unit supports the echo replay option
only to the ping command.
ARP (Address Resolution Protocol):
ARP is used to transmit the Ethernet (physical) address, which is essential to Ethernet communications,
by specifying the IP address. When an ET-LAN unit accesses a station with unknown Ethernet address,
you only need to specify its IP address using the broadcast method.
AUI (Attachment Unit Interface
AUI is a transceiver cable that connects the ET-LAN unit with a transceiver.

1-8
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)
- Computer link communications can be realized by transmitting MEWTOCOL-COM data format from the
computer 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 done
through 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 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.
- 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.
- The maximum amount of data that can be transferred by execution of one data transfer instruction is
1020 words.
Key Point:
- 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.
- 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.
- 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.
- Hierarchical communication via other MEWNET networks is also possible.
- When using the data transfer function, we recommend that you use TCP/IP to guarantee
communications reliability.
- 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.

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Transparent Communication Function
With the transparent communication function, transparent data transmission and reception between
computer and programmable controller and programmable controller and programmable controller is
possible.
Storage and extraction of the communication data at the programmable controller is carried out by
reading from and writing to the ET-LAN unit’s shared memory communication buffer. The communication
requests are performed by switching on and off bits in the I/O or shared memory handshake areas.
Key Point:
- With transparent communication, either the computer or programmable controller specifies the IP
address, and they open a mutual connection with the communication partner. After opening a
connection, communication processing on the programmable controller side is done by the ladder
program reading from and writing to the communication buffer of shared memory, and executing the
communication requests.
- With the transparent communication function and the MEWTOCOL communications function (computer
link and data transfer), you can simultaneously use a maximum of eight connections with one ET-LAN
unit.

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1.2.3 Self Diagnosis Functions
Hardware and communication status check function
The ET-LAN unit is equipped with a self-diagnosis function that monitors the hardware (CPU unit and
memory) and the communication status during operation. You can check the self diagnosis results using
the LEDs on the unit, or by checking the contents of error log area in the shared memory.
Test mode operation function
The ET-LAN unit is reequipped with a test mode operation function for checking the hardware (memory
check and communications check) and for performing internal and external loop back tests. You can
check the results of the test mode operation function using the LEDs on the unit, or by checking the
contents of error log area in the shared memory.
Error log function
The ET-LAN unit is equipped with an error log function that records hardware and communications faults
in the order that they occur. You can read out the contents of error log from the error log area in the
shared memory.