Creating and handling Profibus devices

This article explains how to create and handle Profibus Master and Slave devices via TwinCAT Automation Interface. It consists of following main points:

Creating and adding a Profibus Master

1. To create a Profibus Master device, open a new or an existing TwinCAT configuration
2. Scan all the devices. (These actions can also be performed via Automation Interface.)
Creating and handling Profibus devices 1:
3. Create a system manager object and navigate to devices

Code Snippet (C#):

project = solution.Projects.Item(1);
sysman = (ItcSysManager)project.Object;
ITcSmTreeItem io = (ITcSmTreeItem)sysman.LookupTreeItem("TIID");

Code Snippet (Powershell):

$project = $sln.Projects.Items(1)
$sysman = $project.Object 
$io = $sysman.LookupTreeItem("TIID")

To add a Profibus master, use ITcSmTreeItem:CreateChild method.

Code Snippet (C#):

ITcSmTreeItem5 profi_master = (ITcSmTreeItem5)io.CreateChild("Device 2 (EL6731)", 86, "", null);

Code Snippet (Powershell):

$profi_master = $io.CreateChild("Device 2 (EL6731) ", "86", "", $null)

For other Profibus Masters, enter the correct ItemSubtype listed here. This will add the new device as shown in the screenshot:

Creating and handling Profibus devices 2:

Searching and claiming a Profibus Master device from the list:

It is necessary to configure the newly added Profibus master, which is usually done in TwinCAT by pressing the search button and selecting the correct device from the list:

Creating and handling Profibus devices 3:

This can be done via Automation Interface:

Code Snippet (C#):

string availableMaster = profi_master.ResourcesCount;
profi_master.ClaimResources(1);

Code Snippet (Powershell):

$availableMaster = $profi_master.ResourcesCount
$profi_master.ClaimResources(1)

The ITcSmTreeItem5:ResourcesCount gives out the number of compatible Profibus master devices, and the ITcSmTreeItem5:ClaimResources takes the index of the CANOpen device to be configured as the master.

Creating and adding a Profibus slave

A Profibus slave can be added to the current configuration as shown below:

Code Snippet (C#):

ITcSmTreeItem5 profi_slave = (ITcSmTreeItem5)io.CreateChild("Device 3 (EL6731-0010)", 97, null);

Code Snippet (Powershell):

$profi_slave = $io.CreateChild("Device 3 (EL6731-0010)", "97", "", $null)

Searching and claiming a Profibus slave

Similar to Profibus master, number of Profibus slaves can be published by following code:

Code Snippet (C#):

string availableSlaves = profi_slave.ResourcesCount;
profi_slave.ClaimResource(1);

Code Snippet (Powershell):

$availableSlaves = $profi_slave.ResourcesCount
$profi_slave.ClaimResources(1)

The last line in code claims the EL6731-0010 as the Profibus slave, similar to the dialog box that appears in TwinCAT user interface.

Creating and handling Profibus devices 4:

Changing fieldbus address

To change the the fieldbus address (station no.) of a profibus box in a configuration, an instance of the TwinCAT System Manager has to be created and the configuration has to be opened. The LookupTreeItem method of the ITcSysManager interface returns a ITcSmTreeItem interface pointer implemented by the tree item referenced by its pathname. This interface contains a ConsumeXml method of the tree item.

Procedure

The Procedure to create the ITcSysManager interface (the 'sysMan' instance here) is described in the chapter Accessing TwinCAT Configurations. This interface has a LookupTreeItem method that returns a ITcSmTreeItem pointer to a specific tree item given by its pathname. To change the the fieldbus address (station no.) of a profibus box "TIID^Device 1 (FC310x)^Box 1 (BK3100)" to 44 the following code can be used:

Code Snippet (C#): 

ItcSmTreeItem item = sysMan.LookupTreeItem("TIID^Device 1 (FC310x)^Box 1 (BK3100)");
item.ConsumeXml("44");

Code Snippet (PowerShell): 

$item = $sysMan.LookupTreeItem("TIID^Device 1 (FC310x)^Box 1 (BK3100)")
$item.ConsumeXml("44")