This application note describes the use of the Virtual IO Module to integrate data from two DeltaV systems using Modbus TCP/IP, with the VIMs configured as master and slave devices.

Using Modbus TCP/IP and the Virtual IO Module (M-Series controllers) or EIOC (S-Series controllers) is a simple and effective way to link two DeltaV systems together over an Industrial Ethernet network.  The following should be considered when applying this solution:

• In Master/Slave mode, each VIM or EIOC can talk to 16 slaves and 16 masters simultaneously.
• Each DeltaV system will need to have one VIM or EIOC and an IOD-4101, Modbus TCP/IP Driver, for each module.
• DeltaV DST rules for serial card datasets shall apply on each system. Please see the product bulletin for the DeltaV Virtual IO Module Network Gateway for guidelines on DST counting for both the VIM and EIOC.

This application notes demonstrates how to configure one VIM as a Modbus master and another one as a Modbus slave for integration of two DeltaV systems. It shows the configuration parameters for both master and slave VIM. In addition it demonstrates how to configure one of VIM’s ports as slave and the other as master.

VIMNet Explorer Configuration of Master VIM

In the VIMNet Explorer user needs to add master ModbusTCP VIM placeholder. The user can choose the IP address and subnet mask per his/her network requirements.

Next step is to commission the VIM placeholder to a real physical VIM card.

The following step is to add a SLAVE VIM device with device address and IP address. The IP address needs to match configured slave VIM’s IP address.

Next step is to upload the configuration to the master VIM. Right mouse click on the Master_VIM placeholder and select VIM Configuration Upload as shown below.

VIMNet Explorer Configuration of Slave VIM

In the VIMNet Explorer user needs to add ModbusTCP VIM placeholder for Slave VIM. The user can choose the IP address and subnet mask per his/her network requirements.

Next step is to commission the VIM placeholder to a real physical VIM card.

The following step is to add a SLAVE VIM device with device address and IP address. The IP address needs to match configured slave VIM’s IP address.

Next step is to upload the configuration to the slave VIM. Right mouse click on the Slave_VIM placeholder and select VIM Configuration Upload as shown below.

DeltaV Configuration of Master VIM

The DeltaV configuration of datasets is very simple. It starts by Auto-sensing for new IO cards.

Once the 4 Programmable Serial cards are inserted, the IO needs to be downloaded.

In order to start configuring devices user needs to choose the card and expand it to see the ports. Right mouse click on Port1 and go to Properties. Check the checkbox to enable this port as shown below.

Click on Advanced tab. The following dialog will appear:

In this dialog, leave the default selection as Master mode. Then configure retry count, message timeout and transmit delay according to your application. The serial parameters on Communications tab are not used for VIM communications.

Next step is to right mouse click on Port and Add Serial Device. It opens the following dialog box, where user needs to specify the device address and description. Then click OK.

Next, user needs to configure datasets in the Serial Device. To add a new dataset, right mouse click on the Serial Device and select New Dataset. The following dialog will appear:

In master mode user can select the direction. It’s optional but user can also add the dataset description to make the configuration more readable.

On the DeltaV tab user will select the DeltaV data type.

On the PLC tab user will select the device data type, starting address (offset), and number of values. In example below, the device data type is 3 or Holding Registers.

The special data tab is not used unless the Floating Point data type is used. In that case, user needs to configure 1 in special data 2.

In another example we have configured a coil dataset.

On the DeltaV tab user needs to select the DeltaV data type.

On the PLC tab user needs to enter the device data type that is equivalent to coils. Starting address is the offset of the full address, and number of values is desired number of values for this dataset.

The special data tab is not used for VIM slave communications except when data type used is floating point with status.

Floating Point Dataset

DeltaV Configuration of Slave VIM

The DeltaV configuration of datasets is very simple. It starts by Auto-sensing for new IO.

Once the 4 Programmable Serial cards are inserted, the IO needs to be downloaded.

In order to start configuring devices user needs to choose the card and expand it to see ports.

Right mouse click on Port1 and go to Properties. Check the checkbox to enable this port as shown below.

Click on Advanced tab. The following dialog will appear:

In this dialog user needs to select the Slave mode. Select the transmit delay. Click OK. The rest of messaging parameters are not available. The parameters under Communications tab are not used for VIM communications.

Next step is to right mouse click on Port and Add Serial Device. It opens the following dialog box, where user needs to specify the device address and description. Then click OK.

Next, user needs to configure datasets in the Serial Device. To add a new dataset, right mouse click on the Serial Device and select New Dataset. The following dialog will appear:

In slave mode the data direction is not significant. It’s optional but user can add the dataset description to make the configuration more readable.

On the DeltaV tab user will select the DeltaV data type.

On the PLC tab user will select the device data type, starting address (offset), and number of values. In example below, the device data type is 3 or Holding Registers.

The special data tab is not used unless the Floating Point data type is used. In that case, user need to configure 1 in special data 2.

In another example we have configured a coil dataset.

On the DeltaV tab user needs to select the DeltaV data type.

On the PLC tab user needs to enter the device data type that is equivalent to coils. Starting address is the offset of the full address, and number of values is desired number of values for this dataset.

The special data tab is not used for unless the data type selected is Floating Point with Status.

Below is the example of DeltaV configuration for Floating Point Slave Dataset.

In the following dialog box user needs to specify value of 1 in special data 2 field. It sends the message to master that data in slave in Floating Point format and vice versa.

Following screen capture shows the VIMNet Diagnostics with the master and slave VIM.