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Networks

Refer to these sections for information about the networks.

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Networks in S7

Profibus DP Network, DPV1, DPV3

In the S7 world, the principal network type for communication with devices is the Profibus DP network in a variety of implementations. Some higher-range

S7-300 and all S7-400 controllers have built-in Profibus master ports.

Profibus Network - Other

Profibus FMS and FDL are for data communication between controllers. They perform a similar function to the industrial Ethernet network, and the configuration is nearly identical. The differences are that Profibus communication processors are required rather than the Ethernet network, and that Profibus cabling will be used.

Profibus DPv2 can be used to connect to servo drives in the S7-315T and

S7-317T controllers for low end motion control.

Industrial Ethernet Network

Siemens industrial Ethernet network is the Siemens variety of the Ethernet network in an industrial environment. It is used mainly for communication between controllers, and for controller-to-programming computer communication.

Apart from some of recent controllers equipped for Profinet, S7 controllers do not have built-in Ethernet ports. An S7 system using Industrial Ethernet will have communication processors mounted in the racks.

Depending on the communication processor, the following protocols can be used:

• S7 (Proprietary protocol for communication between S7 controllers)

• TCP (Transmission Control Protocol) Raw Sockets

• ISO-on-TCP (Extended TCP with additional checking)

• UDP (User Datagram Protocol) Raw Sockets

Application code is required to manage most aspects of communication on these networks.

In the Rockwell Automation environment, this functionality can be implemented using integrated EtherNet/IP ports, EtherNet/IP Bridge modules and/or EWEB modules.

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Profinet

Profinet provides for similar Profibus DP functionality on an Industrial

Ethernet with the same programming overhead requirements. A network using

Profinet is similar to Profibus except for different cable and connectors, and use Ethernet field interface modules rather than Profibus. Controllers with a built-in Profinet interface or a communication processor that is equipped for

Profinet are used to connect to the network.

Alternatively, an existing Profibus DP network can be bridged to Profinet, either with a proxy or by using the Profibus DP port of a Profinet-equipped controller.

Some Profinet field interface modules have multiple RJ45 ports with an integrated switch, to allow a Profibus-type line bus topology, if required.

Profinet provides these three communication possibilities:

• Profinet CBA (Component Based Automation), which is primarily used for controller to controller communication and uses standard Ethernet hardware and the TCP/IP software stack.

• Profinet IO for scheduled transfers such as Drives or I/O modules and uses standard Ethernet hardware, but bypasses the TCP/IP software stack.

• Profinet IRT (Isochronous Real Time) for motion control applications which uses Profinet specific hardware and also bypasses the TCP/IP software stack and must exist on a protected network segment.

If the Profinet CBA framework is used, then Profibus, Profinet and Industrial

Ethernet networks can be integrated by graphical configuration, with reduced need for additional programming. Rockwell Automation EtherNet/IP networks provide this functionality using standard hardware and the standard

TCP/IP software stack utilizing built-in functions like the Message (MSG) instruction and produced/consumed tags.

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Hardware Conversion Chapter 1

Networks in Logix

NetLinx is the term identifying the Rockwell Automation solution in the area of networking technologies. The following are the primary networks used in

Logix systems:

• EtherNet/IP

• ControlNet

• DeviceNet

These networks have a variety of notable features. All are designed under the

Common Industrial Protocol (CIP), which enables you to control, configure and collect data over any of the NetLinx networks. As a result, data can flow between different networks without any need for protocol translation software or proxies.

An engineer who is becoming familiar with Logix systems may be impressed by the integrated nature and elegance in configuration of Logix networks.

EtherNet/IP Network

The EtherNet/IP network offers a full suite of control, configuration, and data collection services. It uses TCP/IP for general messaging/information exchange and UDP/IP for I/O messaging. It is most often used in these types of configurations:

• General I/O control

• Data exchange among controllers

• Connecting many computers

• Connecting many devices

• Connectivity to enterprise systems

• Integration of Safety devices

• Motion control (future)

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Typical Ethernet/IP Example

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Hardware Conversion Chapter 1

ControlNet Network

ControlNet is a real-time control network that provides transport of both time-critical I/O and interlocking data and messaging data, including upload/download of programming and configuration data on a single physical media link. It is most often used in these types of configurations:

• General I/O control

• Data exchange among controllers

• Backbone to multiple distributed DeviceNet networks

Typical ControlNet Example

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Chapter 1 Hardware Conversion

DeviceNet Network

The DeviceNet network is a solution for low-level industrial device networking. Designed for devices with a low data volume per device for real time operation. It is most often used in these types of configurations:

• Applications containing distributed devices with a few points

• Network of third-party drives and other “simple” third-party devices

• Systems in which devices need to be connected directly to the network with data and power in the same connection

• When advanced diagnostic information is required

Typical DeviceNet Example

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