MODBUS TCP Protocol

Communication Setup: Xpanel

Create a new device

To create a new device, go to [Tools] → [I/O Devices] or click the icon on the main toolbar. The ‘I/O Device Configuration’ dialog box will pop up. Click the [New Device] button to open the ‘I/O Device Selection’ dialog box.

I/O Device Name: Give a device name. This name will be used in the tag configuration window of the database accompanied by the ‘Station Name’.

Select a device type

After clicking the [Ok] button on the previous step, the ‘Ethernet Communication Configuration’ dialog box will pop up.

In this window, select the ‘MODBUS TCP’ as the ‘Device type’ and configure the proper Ethernet communication parameters. Ensure that those parameters are matched with the device’s configuration. See the Communication Configuration section for more information.

Create a station

Move to the [Station] tab of the ‘Ethernet Communication Configuration’ dialog box. In this dialog box, all the connected PLC stations can be configured and registered to the Xpanel.

Each field can be configured as follows:

Station Name: STN

Give a name to the PLC. This name will be used in the database window accompanied by the ‘Device Name’.

Station Type: MODBUS

Choose the type of connected PLC among the “Modbus TCP”.

Network ID: 0

Sum of MODBUS/TCP devices here its own station number.

Socket Port No: 502

This port number is dedicated to MODBUS/TCP.

16Bit Data Swap

This option swaps bytes of all word- or double-word-sized data. The following diagram shows an example of byte swapping.

Almost all of the data types will be influenced by this option except INT8 / UINT8 / BCD8 / UBCD8.

32Bit Data Swap

This option swaps words of all double-word-sized data. The following diagram shows an example of word swapping.

INT32 / UINT32 / BCD32 / UBCD32 / FLOAT type of Tag values will be influenced by this option.

Using Checksum: This field has no effect. This MODBUS driver always uses a checksum.

Comm. Error Message Pop Up: When this item is checked, Xpanel displays a communication error message box for every Rx and Tx error. Otherwise (unchecked), Xpanel does not display a message for communication errors. This message box will close automatically after a few seconds.

See the Communication Configuration section for more information about the remaining parameters.

Address and Function Codes

The following table shows the list of valid address ranges and used MODBUS function codes for each address area.

The symbol character has to be placed in the first position of the address string. The address number follows the symbol character.

Area	Symbol	Analog Tag	Digital Tag	Read	Write
Coil	0		000001 - 029999¹	1	5
Input	1		100001 - 129999	2
Holding Register	4	400001 - 429999		3	6, 16²
Input Register	3	300001 - 329999		4

The symbol character does not behave as a number. For example, 400100 and 40100 designate the same memory area (holding register 100).
Code 16 is issued for writing double words or when the recipe write function is activated. When writing single words, code 6 is used.

The memory areas listed above are provided for general purposes. The actual available memory area and range of each area should be checked with the manual for the connecting device. The ‘Read’/’Write’ columns show the MODBUS function codes used in this communication driver.
The symbol character (0, 1, 3, or 4) must be placed in the first position of the address string. The address number follows the symbol character.

Communication Cable Wiring

This interface is satisfied with standard IEEE802.3 about the 10BaseT/100BaseTX. You can configure the cable and allocation pin number of RJ45 as shown below.

RJ45 Connector	RJ45 Jack

Direct Cable: Host ↔︎ HUB

Cable	No	Color	Color	No	Cable
	1	Orange/White	Orange/White	1
	2	Orange	Orange	2
	3	Green/White	Green/White	3
	4	Blue	Blue	4
	5	Blue/White	Blue/White	5
	6	Green	Green	6
	7	Brown/White	Brown/White	7
	8	Brown	Brown	8

Crossover Cable: Host ↔︎ Host

Cable	No	Color	Color	No	Cable
	1	Orange/White	Green/White	1
	2	Orange	Green	2
	3	Green/White	Orange/White	3
	4	Blue	Blue	4
	5	Blue/White	Blue/White	5
	6	Green	Orange	6
	7	Brown/White	Brown/White	7
	8	Brown	Brown	8