Connect to Devices in Modbus Explorer

Communicate over Modbus Serial RTU

Follow these steps in the Modbus Explorer to communicate with a Modbus® instrument over Serial RTU.

  1. In the Configure tab, set the following communication parameters in the toolstrip to configure the connection to your device:

    Port: Serial port Modbus server is connected to, for example, COM1.
    Baud Rate: Bit transmission rate for serial port communication. The default is 9600 bits per seconds, but the actual required value is device-dependent. Change the value in the drop-down if your device requires a different baud rate. Enter your baud rate value if it is not in the list.
    Parity: Type of parity checking. Valid choices are none (default), even, and odd. The actual required value is device-dependent. If set to the default of none, parity checking is not performed, and the parity bit is not transmitted.
    Stop Bits: Number of bits used to indicate the end of data transmission. Valid choices are 1 (default) and 2. The actual required value is device-dependent, though 1 is typical for even/odd parity and 2 for no parity.
    Data Bits: Number of data bits to transmit. The default is 8, which is the Modbus standard for Serial RTU. Other valid values are 5, 6, and 7.
    Timeout: Maximum time in seconds to wait for a response from the Modbus server, specified as a positive value. The default is 3. You can edit the value to increase or decrease the timeout.
    Byte Order: Byte order of values written to or read from 16-bit registers. The default is Big Endian, as specified by the Modbus standard. If your device requires Little Endian, change the value in the drop-down.
    Word Order: Word order for register reads and writes that span multiple 16-bit registers. The default is Big Endian, and it is device-specific. If your device requires Little Endian, change the value in the drop-down.

  2. Set the following read parameters in the toolstrip to configure the reading of data from your device:

    Server ID: Address of the server to send the read command to, specified as a double. If you do not specify a Server ID, the default of 1 is used. Valid values are 1-247.
    Register Type: Target area to read. You can perform a Modbus read operation on four types of targets: coils, inputs, input registers, and holding registers. Use the drop-down to select your type.
    Register Address: Starting address to read from, specified as a double. Enter the number for your starting address.
    Precision: Data format of the register being read from on the Modbus server. For coils and inputs, the precision is always bit. For holding registers and input registers, you can specify precisions such as uint16.

  3. To test the configuration, press the Read button. If your configuration parameters are correct, the read is successful and the Read Value fills in with the value from the read. If you get an error, adjust the parameters until the read is successful.

    This value needs to match the value listed in your device manual. Make sure this value and the other configuration parameters match the specifications for your device.

  4. Once you have a correct read value, press the Confirm Parameters button. The rest of the tab appears, and your device is listed in the Device List on the left side of the app.

  5. Use the table to set up reads from your device. The register details you enter in the Configure tab are shown in the first row of the register table. The buttons in the toolstrip are used to insert rows into the table and to move or delete them. Then add information to the rows. Each row represents a data read from the listed target type and address.

    Alternatively, you can use the Import button to import a table of information that you previously exported.

For more detailed information about using the Modbus Explorer to read and write data, see Use the Modbus Explorer App.

Communicate over Modbus TCP/IP

Follow these steps In the Modbus Explorer to communicate with a Modbus instrument over TCP/IP.

  1. In the Configure tab opens, set the following communication parameters in the toolstrip to configure the connection to your device:

    Device Address: IP address of Modbus server, for example, 192.168.2.20. This parameter is required to make the connection.
    Port: Remote port used by Modbus server. The default is 502. Change if using a different port number.
    Timeout: Maximum time in seconds to wait for a response from the Modbus server, specified as a positive value. The default is 3. You can edit the value to increase or decrease the timeout.
    Byte Order: Byte order of values written to or read from 16-bit registers. The default is Big Endian, as specified by the Modbus standard. If your device requires Little Endian, change the value in the drop-down.
    Word Order: Word order for register reads and writes that span multiple 16-bit registers. The default is Big Endian, and it is device-specific. If your device requires Little Endian, change the value in the drop-down.

  2. Set the following read parameters in the toolstrip to configure the reading of data from your device:

    Server ID: Address of the server to send the read command to, specified as a double. If you do not specify a Server ID, the default of 1 is used. Valid values are 1-247.
    Register Type: Target area to read. You can perform a Modbus read operation on four types of targets: coils, inputs, input registers, and holding registers. Use the drop-down to select your type.
    Register Address: Starting address to read from, specified as a double. Enter the number for your starting address.
    Precision: Data format of the register being read from on the Modbus server. For coils and inputs, the precision is always bit. For holding registers and input registers, you can specify precisions such as uint16.

  3. To test the configuration, press the Read button. If your configuration parameters are correct, the read is successful and the Read Value fills in with the value from the read. If you get an error, adjust the parameters until the read is successful.

    This value needs to match the value listed in your device manual. Make sure this value and the other configuration parameters match the specifications for your device.

  4. Once you have a correct read value, press the Confirm Parameters button. The rest of the tab appears, and your device is listed in the Device List on the left side of the app.

  5. Use the table to set up reads from your device. The register details you enter in the Configure tab are shown in the first row of the register table. The buttons in the toolstrip are used to insert rows into the table and to move or delete them. Then add information to the rows. Each row represents a data read from the listed target type and address.

    Alternatively, you can use the Import button to import a table of information that you previously exported.

For more detailed information about using the Modbus Explorer to read and write data, see Use the Modbus Explorer App.