Configuring Modbus client connections (LOGO! 8.FS4 and later versions only)
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Note
If you can connect a device to LOGO! 8.FS4 both with S7 and Modbus connection, Siemens recommends you connect the device with S7 connection. |
Each Modbus connection can be configured as a client or a server, in which the local IP and remote IP are configured respectively. The server is the data source side in communication, it sends information that responds to the requests from the other side - the client.
To configure the client or server connections of each LOGO! connection, double-click the connection.
Right click the desired connection and choose to add a client connection.
Double-click the connection item to configure the client connection.
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① |
Here you define the properties of the Server. The remote IP address is the IP address of the Server or the gateway of the Server that you want to connect. |
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② |
Here you define the properties of the data transfer connection. (Read:Client <- Server, Write: Client -> Server) The unit ID is the address of the Modbus RTU device. You can create a maximum of 32 data transfers in a Client connection. In the read process, the local Base Module reads data from the remote server and stores it; in the write process, the local Base Module writes data to the remote server. You can store data either on the local Base Module or the remote Server by specifying the corresponding column. |
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③ |
Here you define the time interval that LOGO! Base Module synchronizes the data with the server. You can select the check box and input the specified time interval. |
Modbus data transfer configuration
You can set the following values in the data transfer table in configuring client connections:
Click the following drop-down menu to choose the data value for transferring.
Input one address in the address field.
If you configured VM mapping, you can also click
to display the VM mapping table as below:
In the VM mapping table, you can perform the following operations:
Click a column to choose the desired address or click and drag down and up to choose multiple addresses.
Click the mapping fields to switch to the parameter VM mapping dialog.
Click and drag the black arrow at the bottom right corner to expand or shrink the table.
See Tools -> Parameter VM Mapping (0BA7 and later versions only) for more information about the VM mapping.
Click the empty drop-down menu to choose data transfer directions.
Input the other address.
To add or remove rows, right-click an existing row to enable the buttons.
Save your changes.
Configuring Modbus server connections
Double-click the connection item to configure the server connection.
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Note
If the Server in this connection is a SIMATIC Modbus or SIMATIC HMI, you must configure the server connection on the added device. |
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Here you define the properties of the Server.
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Data transfer restrictions
The table below describes the range and local address restrictions for client connections.
Read requests:
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Local address (LOGO!) |
Remote address (Modbus compatible device) |
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|---|---|---|---|
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Address Type |
Range |
Address Type |
Range |
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I Q M V |
1 - 24 bit 1 - 20 bit 1 - 64 bit 0.0 - 850.7 bit |
Coil Discrete Input (DI) |
1 to 65535 bit |
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VW AQ AM AI |
0 - 850 word 1 - 8 word 1 - 64 word 1 - 8 word |
Holding Register (HR) Input Register (IR) |
1 to 65535 word |
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Note
Address Type:
Local address + Data length - 1 ≤ 850 |
The table below describes the range and local address restrictions of client connection.
Write requests:
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Local address (LOGO!) |
Remote address (Modbus compatible device) |
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|---|---|---|---|
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Address Type |
Range |
Address Type |
Range |
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I Q M V |
1 - 24 bit 1 - 20 bit 1 - 64 bit 0.0 - 850.7 bit |
Coil
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1 to 65535 bit
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VW AQ AM AI |
0 - 850 word 1 - 8 word 1 - 64 word 1 - 8 word |
Holding Register (HR) |
1 to 65535 word |
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Note
The values should follow the rule: Local address + Data length - 1 ≤ Max value of Local address type. |