XMC Modbus TCP Client Setup

The XMC has Modbus TCP capability with the built in ethernet port. Modbus TCP uses port number 502. The XMC requires a library provided by Automationdirect to use Modbus TCP Client functionality. There is a unique library for the XMC-E08A/XMC-E08A-DC and XMC-E16A/XMC-E16A-DC.

  • XMC-E08A/XMC-E08A-DC version can be downloaded here.

  • XMC-E16A/XMC-E16A-DC version can be downloaded here.

  • Sample Programs can be downloaded here.

Function Codes Modbus Transcription
Function Code 01 (hex:01) Read Coils
Function Code 02 (hex:02) Read Discrete Inputs
Function Code 03 (hex:03) Read Holding Registers
Function Code 04 (hex:04) Read Input Registers
Function Code 05 (hex:05) Write Single Coil
Function Code 06 (hex:06) Write Single Register
Function Code 15 (hex:0F) Write Multiple Coils
Function Code 16 (hex:10) Write Multiple Registers
Step Action
1 Download the library for your model of XMC (see links at start of topic).
2 Open your XG5000 project for the XMC.
3 In the Project window, right-click on Library. Select Import From File รจ Library
4

Select the library for your XMC. This example is for the XMC-E16A/XMC-E16A-DC. Press Open.
5

Library function blocks will be populated in the Library section of the Project window.

SOCKET_TCPCONNECT is required to use the XMC Modbus TCP Client function blocks. The function block must be executed to create a TCP connection prior to sending/reading Modbus Data. Depending on the configuration of the connected server, if there is no data communication for a specific period or if the connection is terminated based on the various situations, you may need to close the channel with SOCKET_CLOSE and reconnect again with SOCKET_TCPCONNECT.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
ConnectCH Input Enter the socket service channel to use for the connection (1~8).
LocalPort Input Connect with the specified port number. However, if it is 0, an empty TCP port other than the well-known port is automatically assigned (1~65535).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec Waiting
TargetIP Input Destination IP to connect (0~255).
TargetPort Input Port number of device being connected to (1~65535).
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorID Output Error Identification value.
LocalPortOut Output Local port number assigned to the connection (1~65535).

XMC Dedicated Ethernet Connections

The XMC has a default of 3 dedicated connections for the built-in Ethernet port. This can be changed to a value between 1-8 in the Ethernet settings screen. This value corresponds to the ConnectCH input value of the SOCKET_TCPCONNECT function block.

Step Action
1

Double-click on Local Ethernet Parameter in the Project window.
2

Modify No. of Dedicated Connections value to the number of TCP sockets your application will need.

SOCKET_TCPCONNECT Example

SOCKET_CLOSE is used to close a TCP connection to a target device. It must be executed if attempting to connect to a target device that has stopped communicating or timed out.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel of the connection to close (1~8).
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorID Output Error Identification value.

SOCKET_CLOSE Example

This function block is used to perform a Modbus Function Code 01 read of coils. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server (0~255).
Transaction Input Transaction number of the Modbus frame (16#0 ~ 16#FFFF).
Address Input Starting address of coils to be read (0~65535).
QtyCoils Input Quantity of coils to be read (0~2000).
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.
Coils Output Value of the Coils being read.

MODBUS_READ_COILS_FC01 Example

This function block is used to perform a Modbus Function Code 02 read of discrete inputs. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server (0~255).
Transaction Input Transaction number of the Modbus frame (16#0 ~ 16#FFFF).
Address Input Starting address of discrete inputs to be read (0~65535).
QtyCoils Input Quantity of discrete inputs to be read (0~2000).
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.
Coils Output Value of the discrete inputs being read.

MODBUS_READ_DISCRETE_INPUTS_FC02 Example

This function block is used to perform a Modbus Function Code 03 read of a holding register. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server (0~255).
Transaction Input Transaction number of the Modbus frame (16#0 ~ 16#FFFF).
Address Input Starting address of holding registers to be read (0~65535).
RegisterQty Input Quantity of holding registers to be read (0~125).
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.
Registers Output Value of the holding registers being read.

MODBUS_READ_HOLDING_REGISTER_FC03 Example

This function block is used to perform a Modbus Function Code 04 read of input registers. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server (0~255).
Transaction Input Transaction number of the Modbus frame (16#0 ~ 16#FFFF).
Address Input Starting address of input registers to be read (0~65535).
RegisterQty Input Quantity of input registers to be read (0~125).
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.
Registers Output Value of the input registers being read.

MODBUS_READ_INPUT_REGISTERS_FC04 Example

This function block is used to perform a Modbus Function Code 05 write of a single coil. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server (0~255).
Transaction Input Transaction number of the Modbus frame (16#0 ~ 16#FFFF).
Address Input Address of Coil to write (0~65535).
Coil Input Data to write.
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.

MODBUS_WRITE_SINGLE_COIL_FC05 Example

This function block is used to perform a Modbus Function Code 06 write of a single register. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server. (0~255)
Transaction Input Transaction number of the Modbus frame. (16#0 ~ 16#FFFF)
Address Input Address of Register to write. (0~65535)
Register Input Data to write.
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.

MODBUS_WRITE_SINGLE_REGISTER_FC06 Example

This function block is used to perform a Modbus Function Code 15 write of multiple coils. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Type Element Name Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec waiting
UnitID Input Identification of Modbus TCP server (0~255).
Transaction Input Transaction number of the Modbus frame (16#0 ~ 16#FFFF).
Address Input Address of Coils to write (0~65535).
QtyCoils Input Amount of data to write.
Coils Input Data to write.
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.

MODBUS_WRITE_MULTIPLE_COILS_FC15 Example

This function block is used to perform a Modbus Function Code 16 write of multiple registers. It is required to execute SOCKET_TCPCONNECT prior to executing this function block.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Channel Input Enter the socket service channel to use for the established connection (1~8).
Timeout Input

Timeout time*

  • 0: no timeout 

  • 1~65535 : input value

* 1 sec Waiting
UnitID Input Identification of Modbus TCP server. (0~255)
Transaction Input Transaction number of the Modbus frame. (16#0 ~ 16#FFFF)
Address Input Starting address of Registers to write. (0~65535)
RegisterQty Input Quantity of registers to write (0~123)
Registers Input Data to write.
DONE Output Status that function block is done.
Busy Output Function block is executing.
Error Output Status that an error occurred.
ErrorString Output Details of error that occurred.

MODBUS_WRITE_MULTIPLE_REGISTERS_FC16 Example

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LM202