The slave's I/O Modules define the information on the network available to the master. As such, it is best to define the all the slaves in a network before creating and configuring the master.

I/O Modules

Right click on a NIM-7 in the hardware interface file and left click on Module properties. The Module properties dialog comes up. Left click on the lower PROFIBUS entry on the left to bring up the dialog in Figure 9.35. Among other things, this dialog indicates to the modules if it should be operating as a Master or Slave. Ensure the NIM-7 is configured as a slave by left clicking on SLAVE in the dropdown box.


Figure 9.35. PROFIBUS Slave Attribute

Recall that the I/O modules are identified as input or output from the master's perspective. The I/O module definitions are configured in the slave memory space, so the dialog for performing that definition is accessed via the slaves' module properties dialog. Left click on IO Modules to bring up the dialog in Figure 9.36 to begin adding data block definitions.

Figure 9.36. IO Modules Before they are Defined

Left click on Add to begin defining the first data transmission. In the example here (Figure 9.37) we wish to transmit 20 words from the slave as input to the master and one byte as output from the master to the slave. Left click on OK to save these definitions.

Figure 9.37. Two I/O Modules Defined

Notice the Delete and Move buttons. They allow rearrangement and removal of slot definitions.


The fields in the IO Module definition dialog are as follows:

• Slot is used to identify the address of a module within a Design Pad slave.
• Size defines the message length in bytes. A Drop Down allows selecting the possible lengths from 0 to 244 bytes.
• Direction specifies whether the message is input module or an output module (recall this is from the perspective of the master).
• Type describes the data as byte (8 bits), word (16 bits) or empty (0), which determines the actual message length.
• Consistence field tells whether the data in this memory block is updated at the same time (True) or that some of it might be out of date.
• Symbolic Name allows for identifying the message with a meaningful name rather than just its slot number

Maximum and Current I/O Modules memory usage information is displayed at the top of the dialog. The maximum column indicates the available data resources on a slave – 368 bytes across 24 I/O Modules. A maximum of 244 bytes can be sent in one type of I/O module and the rest may be used by the other type. The current column shows the calculation of resources used by the slot configuration defined on this slave.

Endianness of Data in the I/O Modules

The standard for PROFIBUS is to store data in Big Endian (most significant byte is stored at the lowest memory location address). All information transferred into I/O Modules using Fairmount Automation equipment will be stored in a Big Endian format.

User Parameter Data

Left clicking on Parameters from Module Properties brings up Figure 9.38.

Figure 9.38. Parameter Octets

These configuration parameters are the slave's User Parameter Data which help indicate some customizable information about this device. There are three bytes allocated to User Parameter Data. These bytes and are predefined as follows in the Fairmount Default GSD file:

Byte 0, Bit 7: DPv1 device (1 = Enabled / 0 = Disabled)
Byte 0, Bit 6: Fail Safe active (1 = On / 0 = Off)
Byte 0, Bits 5 to 0: Not defined

Byte 1, Bit 7: Pull Plug Alarm (1 = On / 0 = Off)
Byte 1, Bit 6: Process Alarm (1 = On / 0 = Off)
Byte 1, Bit 5: Diagnostic Alarm (1 = On / 0 = Off)
Byte 1, Bit 4: Manufacturer Specific Alarm (1 = On / 0 = Off)
Byte 1, Bit 3: Status Alarm (1 = On / 0 = Off)
Byte 1, Bit 2: Update Alarm (1 = On / 0 = Off)
Byte 1, Bits 1 to 0: Not defined

Byte 2, Bits 7 to 3: Not defined
Byte 2, Bits 2 to 0: 3 bits map into the following Alarm Mode selection:

So, the default Design Pad setting of 0x00 for Byte 0, 0xFC for Byte 1, and 0x07 for Byte 2 results in the following User Parameter Settings:

The defined value for any or all of these bits / bytes are fixed for a particular device and cannot be changed.

Now that there are I/O module slots defined, broadcasters and receivers can be added to the slave's schema to exchange information with those I/O module slot definitions.

Adding Broadcasters and Receivers to the Slave's Schema

Right click on empty space in a schema to bring up the Operators menu. Left click on Generic Hardware operators  Networking  PROFIBus  Broadcast to make use of a Broadcast operator (Figure 9.39 and Figure 9.40).

Figure 9.39. Adding a PROFIBUS Broadcast Operator


Figure 9.40. PROFIBUS Broadcast Operator

When the broadcast operator is first added to the schema it defaults to a Boolean value broadcaster. Left double click on the operator to access its properties to change the type of data it transmits (Figure 9.41). In this example, we are selecting a 4 byte IEEE floating point. Note that other formats are available including structures. Also note that you can shift where in the I/O Module memory block that the data will reside by setting the offset parameter.

Figure 9.41. PROFIBUS Broadcast Operator Properties

The PROFIBUS Broadcast Generic hardware operator must be linked to an I/O Module (in this case, an Input Module) in the desired NIM-7. To create the link, right click on the operator to Connect to Hardware (Figure 9.42). All of the slave's input slots available to the broadcast operator are listed in the Network Interface Drop Down list (Figure 9.43). Select the desired Input Module for the particular Broadcast. Like other Generic Hardware operators, the Broadcast operator's color changes when the link is complete. Note in Figure 9.43 if more than one NIM-7 is defined in the module you must choose it before selecting the proper I/O module.

Figure 9.42. Link the Broadcast Operator to Hardware

Figure 9.43. Select the I/O Module for the Broadcast Operator

If the slave receives information from its master(s), add PROFIBUS Receiver operators as required in much the same way as broadcast operators. Right click on empty space in a schema to bring up the Operators menu. Left click on Generic Hardware operators  Networking  PROFIBus  Receiver to make use of a Receiver operator (Figure 9.44).

Figure 9.44. Add a Receiver Operator

Adjust the operator's properties as required and then right click on the operator to connect it to a hardware resource. All of the slave's Output Module slots available to the receiver operator on the selected NIM-7 are listed in the Network Interface Drop Down list (Figure 9.45). Select the appropriate I/O module for the particular receiver.

Figure 9.45. Selecting a PROFIBUS Receiver's Output Slot

Hardware Connections and Network Signal View

Right click on a NIM-7 in the hardware interface file and left click on Hardware Connections. A dialog similar to Figure 9.46 comes up. This dialog lists the names of all the broadcast and receiver operators connected to the I/O Modules in the device.

Figure 9.46. NIM-7 Hardware Connections

Left click on the Workspace Network View and expand the tree for a NIM-7 by left clicking the plus sign to see the message traffic assigned to each NIM-7 (Figure 9.47).


Figure 9.47. PROFIBUS I/O Modules in Network View

Network Station ID

Assign a Station ID to a slave by right clicking on PROFIBUS in the Network View and left clicking on Properties. The Configure Network dialog (Figure 9.48) appears, allowing assignment of a Station ID to each module (NIM-7) on the network. Even if the Fairmount Automation devices on the network are exclusively slaves, they still must have station IDs assigned to them. Design Pad G4 automatically adds a sequential station ID to each module as it is linked to the network. Note that station IDs between one and ten are traditionally reserved for masters on a PROFIBUS network.

Figure 9.48. Station ID Assignment in Network Configuration Dialog

External (3^rd Party) Devices on the PROFIBUS Network

When Fairmount equipment is the master of a network consisting of other manufacturer's PROFIBUS slave devices, those devices need to be represented in Design Pad. In these cases, add an external device module to its own HWI file and link it to the RS-485 PROFIBUS network in the workspace. Then the slot definitions can be configured, or, more likely, the device vendor will supply a GSD file defining the necessary data. Follow these steps to accomplish this:
Configure the external device so it can make use of an RS-485 network. Right click on the external device in the HWI and select Manage Hardware Resources. The dialog allows you to add networking hardware to the device's capabilities. Select RS-485, click on the left arrow to add it to the hardware resource list and press OK to make the assignment.

Figure 9.49. Add RS-485 Capability to a PROFIBUS External Device

Next right click on the device and left click on Module Properties  PROFIBUS to enable the device on the protocol and, optionally, import the GSD file for that device. Don't forget to link the device to the PROFIBUS network using the Attach Network interfaces dialog in the File View Assign Network selection, similar to Figure 9.32.


Figure 9.50. Enable an External Device for PROFIBUS Usage

To import the device GSD file, left click on the Import GSD button, respond to the warning and choose the correct file from the list to complete the device configuration.

You can simulate the external device's functionality and communications activities by linking and programming a schema to it as with any other Fairmount Automation module (Figure 9.52).

Figure 9.51. Adding a Schema for an External Device

Fairmount Automation provides a GSD file (see Appendix A) for use when a Fairmount device is a slave on a network with another manufacturer's device as master. There is also a GSD file for Fairmount devices configured as masters. Both files are available for download from the Fairmount Automation website.

Figure 9.52. Importing a GSD File

PROFIBUS Slave Alarm Broadcast

The Alarm Broadcast operator allows a slave to send several different types of event notifications to its master. The operator provides functionality for the following alarm types:

Diagnostic: A diagnostic alarm signals an event within a defined I/O module slot, for example over-temperature, short circuit, etc. From "Specification for PROFIBUS, Device Description and Device Integration, Volume 1: GSD" , Version 5.1 July 2008.

Process: A process alarm signals the occurrence of an event in the connected process, for instance upper limit value exceeded. ³

Pull: A pull alarm signals the withdrawal of a module at a defined I/O slot. ³

Plug: A plug alarm signals the insertion of a module at a defined I/O slot. From "Specification for PROFIBUS, Device Description and Device Integration, Volume 1: GSD" , Version 5.1 July 2008.

Status: A status alarm signals a change in the state of an I/O module, for instance run, stop or ready. ³

Update: An update alarm signals the change of a parameter in a defined I/O slot, for example, by a local operation or remote access. ³
A detailed overview of Design Pad operator functionality (including PROFIBUS operators) is described in the Design Pad Operator Reference, publication PDG-TR-2011/13.

Defining and Linking to PROFIBUS Communication Networks