Setting parameters for the PROFIBUS interface - TIA Portal

Changing the parameter settings of the PROFIBUS interface

The network-related parameters and bus parameters for the PROFIBUS network can be adapted more precisely. You should first select a default setting and then adapt this to the specific situation.

Requirement

The interface is not assigned to a subnet. If you assign a subnet in the properties of the interface, the settings for the subnet in the project take precedence. In this case, the interface configuration cannot be changed.

Setting defaults for the PROFIBUS interface

To adapt the parameters of the PROFIBUS interface, follow these steps:

1. Select the interface in the project tree.

2. Select the "Properties" command in the shortcut menu of the interface.

   The dialog for configuring the interface opens.

3. Go to "General > Assignment" and select the subnet with which you want to connect the interface in the "Connection to subnet" drop-down list.

4. Under "General > Configuration", select a default for the device and network-related parameters. The defaults are suitable for most configurations. Select one of the following settings:

   • Automatic protocol detection

     You can connect the programming device to MPI or PROFIBUS without having to set bus parameters. At a transmission speed lower than 187.5 Kbps, you may, however, have waiting times of up to one minute. Prerequisite for the automatic detection is a connection to the bus master, which distributes the bus parameters cyclically. With PROFIBUS subnets, cyclic distribution of bus parameters may not be deactivated (default PROFIBUS network setting).

   • MPI

     The "MPI" transmission protocol is selected. Typical parameters are set that are adequate for most configurations. You can change the parameters to your needs, however.

   • PROFIBUS

     The "PROFIBUS" transmission protocol is selected. Typical parameters are set that are adequate for most configurations. You can change the parameters to your needs, however.

Changing the default parameter settings

To adapt the default settings to your requirements, change the parameter setting where necessary in "Configurations > PROFIBUS".

You can set the following device-related parameters:

• Is only master

  An additional verification function to prevent bus disruptions when connecting the PG/PC to the network is disabled because the programming device or PC is the only master on the bus.

  • Do not enable this option unless you have only connected slaves to your programming device or PC.

  • If the "Is only master" check box is enabled, it is not possible to identify the directly connected device in the "Accessible devices" window.

• Own address

  This setting relates to the programming device or PC on which you call up the parameter settings of the interface. Set the local device address of your programming device or PC here.

  • This address must be unique throughout the network.

  • The programming device or PC is addressed using this address in the PROFIBUS network.

• Check

  This enables an additional safety function to prevent bus disruptions when connecting the PG/PC to the network. The driver checks whether the local address is already being used by another station. Active as well as passive stations are taken into consideration in this case. The driver monitors this on the PROFIBUS. The connection of the PG/PC to the network will take longer with the automatic check. To use the check, the driver must support the function. Furthermore, the "Is only master" option must not be selected.

• Timeout

  Set a higher timeout value if, for example, you have problems with long response times on the network.

You can set the following network-related parameters:

• Highest address:

  Select the configured highest device address. Make sure that the same highest station address is set for all devices of a PROFIBUS network.

• Transfer rate:

  Here, you select the transmission speed to be used on the PROFIBUS network.

• Profile:

  You have a choice of four alternatives for the PROFIBUS settings. "DP", "Standard" and "Universal (DP/FMS)" are predefined settings that you cannot change. If you select "User-defined", you can adapt the bus parameters yourself.

  • If you have selected "User-defined", go to "Configurations > PROFIBUS > Bus parameters" in area navigation.

  • If you have selected one of the defaults (DP, Standard or Universal (DP/FMS)), you should select the "Include" check box in "Configurations > PROFIBUS > Bus parameters > Additional parameters". You can then set the number of masters and slaves on the bus. This allows a more precise calculation of the bus parameters and potential bus disruptions can be prevented. The option cannot be selected with a user-defined profile.