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ROC809 Integration with DeltaV using Modbus TCP/IP
By Nobin William
Product: IOD-4101 - Modbus TCP/IP Master Driver (General Modbus TCP/IP Communications)

The following technical note documents and demonstrates the setup and configuration required for integration of ROC809 with the DeltaV Virtual IO Module and Modbus TCP/IP Driver v3.8.3 or higher.

The Architecture for VIM/ROC809 Communications

VIM Configuration

Open the VimNet Explorer and create a new VIO file. Then right-click on the "I/O Net" to add a new Controller as follows:

A new controller called NODE01 will be added. Right-click on the controller and select "New IO VIM."

A new VIM dialog will be displayed as follows:

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Change the VIM Name, IP Address and Subnet Mask as needed, then click "OK" to add the Modbus TCP VIM. Next commission the VIM as documented in the VIM product manual.

The VIM will have 4 serial cards, C57-C60, defined under it. Drill into C57 and right-click on port P01. Select "Add Device." This device represents the ROC809 we will be communicating with.

When "Add Device" is selected, a dialog is displayed as follows:

Specify the ROC’s Modbus address and description. To specify the IP address, click "Edit." This will display the following dialog:

Specify the ROC’s IP address. Select the Protocol as RTU TCP as shown. This is the Groupe Schneider Open ModbusTCP protocol. The default port number is 502. Lastly, leave the Simultaneous Messages parameter as 1. Click "OK." Note that the VIM and ROC SubNet masks must be the same.

Click "OK" again. The VimNet Explorer will now show the device as follows:

Lastly, the configured device has to be uploaded into the VIM’s non-volatile memory. In the VimNet Explorer, right-click on the VIM as follows:

Select "VIM Configuration Upload" to send the VIM configuration into the VIM. This completes the VIM configuration task. All remaining configuration is done at the DeltaV Explorer level as described below.

DeltaV Configuration

After VIM configuration is complete, open the DeltaV Explorer and Auto-Sense the I/O cards. This will insert 4 programmable serial cards at C57-C60 positions as shown below:

Right-click on C57, Port P01 and select "Properties." The following dialog will be displayed. Select the "Enabled" check-box.

Next, click on the "Advanced" tab and configure the parameters as shown. Note that no changes need to be made under the "Communications" tab.

Click "OK"to complete the Port configuration.

Next, right-click on the Port and select "New Serial Device." The following dialog will be displayed:

Specify the device description and device address. This is the ROC’s Modbus address. It must be the same as the address configured for the device in the VimNet Explorer. Click "OK" to complete the device configuration. The device added will be called DEV01.

The last configuration step is to specify the datasets. This will depend on the Modbus registers and ranges available in the ROC.

Adding a Floating Point Input Dataset

Right-click on the device DEV01 and select "New Dataset." The following dialog will be displayed:

Specify the description. In our example, we will read data from the ROC Consequently, the Data direction will be Input as shown. Select the DeltaV tab. The dialog will be as follows:

Select the DeltaV data type depending on the type of data being read from the ROC. In this case, the data type is Floating Point. Select the parameter as shown. Complete the remaining dataset configuration as shown below:

Device data type is used as described in the following table:

Register Type

Device Data Type

Coils

0

Input Status

1

Input Register (16-bit and Floating Point)

2

Holding Register (16-bit and Floating Point)

3

Data start address is specified as the Start Register in the ROC. And the Number of values parameter is 5. Note that the maximum number of values for floating point registers is 50.

Lastly, click on the "Special data" tab and complete as required.

For floating point datasets, the "Special data" registers are used as described below:

Special Data Register

Description

Expected Value

1

Floating Point Byte swapping

0, 1, 2, 3

See manual for description

2

Floating Point register equivalence

0means 1 floating point register is equal to 2 16-bit registers. The VIM will read two 16-bit values for each floating point value.

1means 1 floating point register is equal to 1 floating point register. The VIM will read a single 32-bit value for each floating point value.

Adding a 16-Bit Integer Input Dataset

Right-click on the device DEV01 and select "New Dataset." The following dialog will be displayed:

Specify the description. In our example, we will read register range 7001-7010 from the ROC. Consequently, the Data direction will be Input as shown. Select the DeltaV tab. The dialog will be as follows:

Select the DeltaV data type as 16-bit as shown. Complete the remaining dataset configuration as shown below:

Device data type used will be 3, the Data start address will be 7001, and the number of values to read will be 10. For 16-bit data the maximum number of values is 100.

Lastly, click on the "Special Data" tab and complete as shown below.

This completes the dataset configuration. Download all 4 configured serial cards C57-C60, and then use DeltaV Diagnostics to check communications status.

ROC809 Configuration

The following is a ROC809 configuration used as a reference in this AppNote. It describes the various configuration settings as expected and used for ModbusTCP communications. For all other ROC configuration settings please consult the ROC product manual.

Open the ROCLINK 800 application and connect to a ROC 809. Select the "ROC -> Information" menu option as shown below.

This will open a dialog as follows showing the Modbus address. The Modbus address is used in the VIM and DeltaV device configuration described above.

Next, click on the "Internet" tab. This will show the following dialog:

Under the "Internet" tab, the IP address and SubNet mask of the ROC are specified. These parameters must match those configured into the VIM. The VIM and ROC must be on the same network. The Gateway address specified in the ROC is not used by the VIM. The VIM must have a direct network connection to the ROC, not one that goes through a gateway.

Other tabs in the Device Information dialog should be configured as required for the ROC.

In the ROCLINK 800 application, select the "Configure -> MODBUS -> Registers" menu option as shown below:

This will open a dialog as follows. In this dialog, user must map Modbus registers to internal ROC points. In the following example, some ROC data has been mapped. We use these Modbus register ranges in the DeltaV dataset configuration above.

For details on ROC configuration and register mapping, please consult the ROC product manual.