DeviceNet Controllers

DeviceNet Controllers Selection Guide

What is a DeviceNet Network?

DeviceNet is an application-level network protocol used in industrial automation to facilitate data exchange by interconnecting multiple control devices. It uses the Common Industrial Protocol (CIP) – a producer-consumer communication model – over a Controller Area Network (CAN) media layer, the medium by which various device profiles are connected to the DeviceNet network.

In a nutshell, the DeviceNet network is a digital, connection-based, multi-drop fieldbus system that supports communication between higher-level devices like programmable controllers (e.g., PACs and PLCs) and field-level industrial devices such as sensors (level sensors, flow meters, etc.) and actuators (motors, conveyors, etc.).

DeviceNet networks are commonly used in factory automation to provide an open communication link between plant-floor controllers (e.g., PLCs and PC-based controllers) and industrial I/O devices (including sensors, motor starters, panel displays, bar code readers, limit switches, valve manifolds, and photoelectric sensors) as well as electrical drives (e.g. Variable Frequency Drives), Human Machine Interfaces (HMIs), and many other automation systems from multiple vendors.

Benefits of DeviceNet Networks

DeviceNet networks provide a cost-effective networking solution to distribute and manage simple industrial devices throughout the factory architecture, enabling device-level control and information networking using a single cable for power and signal transmission. They also allow users to connect industrial I/O devices directly to plant-floor controllers without hard-wiring each control device into an I/O module. This eliminates costly and time-consuming hard wiring, allowing for a reduction in network installation costs.

In addition, the direct connectivity offered by DeviceNet networks provides improved information exchange between the interconnected control devices and crucial device-level diagnostics that are unavailable or easily accessible via hard-wired Input/Output interfaces.

DeviceNet Architecture

The DeviceNet protocol follows the OSI (Open Systems Interconnection) conceptual model, which describes seven layers that industrial control devices use to communicate over the network. The seven layers include application, presentation, session, transport, network, data link, and physical layer. As previously mentioned, DeviceNet is based upon the Common Industrial Protocol (CIP) – a media-independent, object-oriented protocol that provides a mechanism for organizing, representing, and sharing data in industrial control devices on a network.

The DeviceNet network implements the CIP technology at the three upper layers of the OSI conceptual model, namely the Session, Presentation, and Application layers, while the bottom four layers (Transport, Network, Data Link, and Physical layers) are adapted to the DeviceNet control application. The diagram below illustrates the DeviceNet architecture.

Transport and Network Layers: These layers establish a communication link with an industrial control device using connection Identifiers (IDs) for the DeviceNet nodes. The Identifiers comprise a Message ID and the control device's MAC (Media Access Control) Address.
Data Link Layer: In DeviceNet, this layer uses the Control Area Network (CAN) – a highly integrated message-based serial bus system– to handle all messaging between programmable controllers and industrial I/O devices on the DeviceNet network.
Physical Layer: This layer of DeviceNet includes a combination of termination resistors, ports, cables, connectors, taps, and nodes in a trunkline/drop-line topology.

Planning a DeviceNet Network

When planning to install a DeviceNet network, you should consider the following:

1. Topology

The DeviceNet cable system supports a trunkline/drop-line topology. You can branch or daisy-chain the network nodes along the drop lines up to 20 feet (6 meters) maximum. The trunk line should be terminated at both ends with 121 Ω (Ohm), 1% (tolerance), 1/4 Watt, or bigger terminating resistors.

2. Number of Nodes

A single DeviceNet network can support a maximum of 64 nodes; hence, you can include one control device on each node address beginning from 0 – 63. Node 00 is reserved for the master DeviceNet scanner, while Node 63 is set aside as a default node number, leaving the other 62 nodes available for connecting industrial I/O devices. Most Allen-Bradley controllers can support several DeviceNet networks, giving users the flexibility to add more nodes if necessary.

3. Type of Physical Media

A variety of DeviceNet physical media are available from which you can choose to meet all your application needs. These include:

A) Round Media

The Round Media contains five wires in a single cable. The five wires are one twisted pair (white and blue) for signal transmission, one twisted pair (black and red) for 24V DC power, plus a drain wire (bare colored). Round media is available in two different cable types, namely:

Thick Cable: This cable has an outer diameter of 0.48 inches (12.2 mm). It is primarily utilized as the trunk line on any DeviceNet network.
Thin Cable: This cable has an outer diameter of 0.27 inches (6.9 mm). It is mainly used as the drop line linking industrial I/O devices to the DeviceNet trunk line via DevicePort or DeviceBox taps, but you can also use it as the DeviceNet trunk line.

The round media (both thin and thick cable types) is typically used for standard DeviceNet installations when:

Distances between the control devices (nodes) to be connected on the DeviceNet network are known and fixed.
A larger overall network distance is needed.
It is preferable to daisy-chain the control devices at the trunk line (i.e., drop lines are not required).

B) Flat Media

The Allen-Bradley KwikLink Flat Media system includes a four-wire flat cable made of one twisted pair (white and blue) for signal transmission and one twisted pair (black and red) for 24V DC power. It’s a modular cabling system, with each flat media connection consisting of the 4-wire flat cable, a hinged tap, Insulation Displacement Connectors (IDCs), and an interface module with a choice of unsealed or sealed micro-QD, and an open-style terminal connection or a terminating resistor.

The KwikLink system is designed to offer maximum network simplicity with 50% savings in installation costs while still supporting up to 64 control devices (nodes). It accomplishes this by allowing quick and easier addition of control devices to the DeviceNet network without stripping or cutting the trunk line. The 4-wire flat cable is also easy to mount, and it’s physically keyed to avoid wiring mishaps.

The KwikLink flat media system is typically used for more modular DeviceNet applications when:

Distances between the nodes (control devices) are less known and are likely to change.
All network wiring is to be carried out on-site.
Future addition of nodes to the DeviceNet network is anticipated.
Drop lines of 0-6 meters (20 feet) each are required.
Bridges/Repeaters are used to provide overall network distances of up to 3 km.

C) DeviceBox Taps

These DeviceNet taps provide a direct connection to a Round Media trunk line. They can connect up to eight (8) nodes to the trunk line using thin cable drop lines, thereby providing terminal strip connections.

D) DevicePort Taps

These multi-port DeviceNet taps connect to a Round media or KwikLink Flat media trunk line via drop cables. They can connect up to eight (8) industrial devices to a DeviceNet network using micro or mini quick disconnects.

E) Pre-terminated Cable

Pre-terminated DeviceNet cables provide connections to ArmorBlock I/O and power supply modules. They are offered in a wide selection of cable lengths and connection configurations.

F) Insulation Displacement Connectors (IDCs)

The IDCs interface DeviceNet drop line cables to a Flat Media trunk line with enhanced plug-and-play capabilities at minimal cost. Their 2-piece hinged base snaps snugly around the 4-wire flat cable at any point along the KwikLink trunk line.

4. Distances

When planning a DeviceNet cabling system, be sure to consider the distance/length of the:

Trunk line
Dropline
The overall distance of all the drop lines in the DeviceNet network

The required data transfer rate and the selected trunk line cable type determine the maximum achievable DeviceNet network distances. In many instances, the maximum network distance is usually the measurement between the trunk line terminating resistors. Refer to the specification charts provided with DeviceNet physical media to determine the maximum cable length you can install without compromising the performance of your network.

5. Scanner Memory

Instead of an Allen-Bradley programmable controller communicating directly to discrete I/O devices on a DeviceNet network, a DeviceNet Scanner module is used to facilitate communication. In a typical DeviceNet configuration, the DeviceNet scanner functions as a communication interface between the programmable controller and DeviceNet Input/Output devices.

The processor writes I/O control data to the memory of the DeviceNet scanner module. But depending on the total number of Input/Output devices connected on a DeviceNet network, the aggregate input and output data sizes can exceed the memory capability of a given DeviceNet scanner module. In such cases, an additional DeviceNet scanner will be required for the control platform.

Hence, ensure that you check the specified input and output sizes of the DeviceNet scanner you intend to use against the total input and output data sizes of your DeviceNet I/O devices to determine if you need additional scanner modules.

6. Communication Interfaces

A wide variety of DeviceNet Connected products are available for almost every industrial automation application, from programmable controllers, operator terminals, and I/O modules to motor controllers to AC & DC drives and energy management systems. These products have an integral DeviceNet interface or connect to the DeviceNet network via an external communication interface. Some of these optional DeviceNet communication interface modules include:

A) Controller Interfaces

Rockwell Automation offers DeviceNet connectivity to the following Allen-Bradley programmable controller platforms: CompactLogix L4x, CompactLogix 5370, Compact GuardLogix L4xS, ControlLogix 5570, CompactLogix L3x, SoftLogix 5800 controllers, MicroLogix 1100/1200/1400/1500 Controllers, and the SLC 500 control platform (SLC 5/02, 5/03, 5/04, and 5/05 Series).

Various controller interfaces are available for connecting the Allen-Bradley controllers to a DeviceNet network. They include:

DeviceNet Interface (DNI) Module: This is a standalone, panel or DIN-rail mounted, DeviceNet-to-DF1 (full-duplex) protocol-conversion device that enables existing DF-1 full-duplex devices, various Allen-Bradley programmable control platforms, and UCMM (Unconnected Message Manager) capable DeviceNet-connected products to communicate over a DeviceNet network. It can function in either peer-to-peer or DeviceNet Slave operating modes. The DeviceNet Interface module is developed for use with MicroLogix 1100/1200/1400/1500 controllers and DF-1 Full-Duplex compliant devices such as PLC-5 programmable controllers, SLC 500 (SLC 5/03, 5/04, and 5/04) processors, and operator interface devices.
DeviceNet Scanners: DeviceNet scanner modules interface between DeviceNet-connected I/O devices and various Allen-Bradley Programmable Logic Controllers (PLCs) and SLC 500 controller platforms. They provide I/O control between a programmable controller and the DeviceNet devices. Also, these scanner modules provide bridging and pass-through capabilities for data collection and configuration of DeviceNet I/O devices while connected to a higher-level control network like Data Highway Plus (DH+), ControlNet, and Ethernet.
DeviceNet Bridge Module (Catalog No. 1756-DNB): This controller interface is an element of the ControlLogix Gateway. It allows communication between several DeviceNet networks over the same communication backplane or among different networks supported within the ControlLogix Gateway. For instance, a device on one DeviceNet network can communicate with a device on another DeviceNet network through the ControlLogix Gateway. Also, a DeviceNet Bridge interface within the ControlLogix Gateway allows communication between a DeviceNet industrial device and a device on another network, such as on Data Highway Plus (DH+), ControlNet, or Ethernet.

B) Operator Interfaces

You can customize your DeviceNet networks for better status and fault reporting with a variety of Allen-Bradley operator interface offerings, including PanelView Standard graphic terminals (Bulletin 2711), PanelView Plus graphic terminals (Bulletin 2711P), PanelView Plus CE graphic terminals (Bulletin 2711P), InView Message Displays (Bulletin 2706), Control Tower Stack Lights (Bulletin 855T), and Push Button Stations (Bulletin 800E).

While PanelView 300, 1000, 600, and 500 Standard operator terminals from Rockwell Automation include a built-in DeviceNet option, other Allen-Bradley PanelView operator terminals require an external DeviceNet communication interface to access the DeviceNet network. Examples of communication interfaces for such PanelView operator terminals include:

2711P-RN10C: This is a DeviceNet communication interface for PanelView Plus 600 and PanelView Plus 400 graphic operator terminals.
2711P-RN10H: This DeviceNet communication module enables PanelView Plus 1500, 1250, 1000, and 700 graphic operator terminals to access a DeviceNet network. It is also compatible with Allen-Bradley PanelView Plus CE models – PanelView Plus CE 1500, 1250, 1000, and 700 graphic operator terminals.

C) Computer Interfaces

PC-ready DeviceNet interface options provide DeviceNet communication for monitoring, configuring, and general programming of industrial devices via PC-based controllers, i.e., an industrial or desktop computer. They include:

DeviceNet PCI Bus Scanner Card (Catalog No. 1784-PCIDS): This is a DeviceNet universal PCI open-bus scanner card that provides users with the capability to link PCI-bus computers to a DeviceNet network for general communication, DeviceNet monitoring & configuration, I/O scanning, and explicit messaging. It is designed for the standard PCI (Peripheral Component Interconnect) bus used in most Personal Computers (PCs) manufactured today.
DeviceNet CompactPCI Bus Scanner Card (Catalog No. 1784-CPCIDS): This DeviceNet communication interface card is designed for the CompactPCI bus used in many industrial computers.
DeviceNet PCD Interface Card (Catalog No. 1784-PCD): This is a Type II PCMCIA form-factor communication interface card that provides an interface between a PCMCIA 2.1-compliant personal computer and the DeviceNet network.
DeviceNet RS-232 PC Interface Module (Catalog No. 1770-KFD): This portable communication interface module enables users to connect a host computer to the DeviceNet network. It connects to the network through a DeviceNet cable and to the host computer via a standard RS-232 serial communication port. Once connected to a given DeviceNet network, the host computer is established as a DeviceNet node.

Available DeviceNet Controller Units

Several DeviceNet controller units are utilized as communication interfaces between Allen-Bradley programmable controllers and various I/O devices connected to a DeviceNet network. This allows device-level I/O control and information networking over the DeviceNet network.

Available DeviceNet controller units include:

A) 1753-DNSI DeviceNet Scanner Module

The 1753-DNSI is a DeviceNet Safety Scanner (communications adapter) for Allen-Bradley GuardPLC Safety Controllers (Bulletin 1753). The scanner module supports safety connections of up to 32 safety Input/Output DeviceNet nodes and a maximum of 63 DeviceNet nodes for standard connections.

Essentially, the 1753-DNSI Safety scanner provides DeviceNet access for GuardPLC 1800 and

GuardPLC 1600 safety controllers. These Allen-Bradley safety controllers support interactive communications (data exchange) via the High-Speed Safety Protocol (HSP). The 1753-DNSI Safety scanner communicates with DeviceNet I/O devices over the network to monitor their status, read inputs, and write outputs. It then exchanges the aggregated data from the DeviceNet nodes with the GuardPLC above safety controllers via HSP.

In addition, the 1753-DNSI Safety scanner module supports communication rates of 125 Kbps (Kilobits per second), 250 Kbps, and 500 Kbps. It has an isolation voltage rating of 30 Volts (continuous). It includes a 1753-CBLDN HSP (High-speed Safety Protocol) cable and an Open-Type enclosure, and it can be panel mounted or installed on a DIN rail.

B) 2711P-RN10C DeviceNet Communication Module

The 2711P-RN10C is a DeviceNet communication interface that lets Allen-Bradley PanelView Plus 600 and PanelView Plus 400 graphic operator terminals connect to a DeviceNet network. The two operator terminals can support scheduled DeviceNet I/O communications with this DeviceNet communication module.

The 2711P-RN10C communication module includes three indicators, namely:

I/O Status Indicator: This is a bi-color (red/green) LED that provides status information of the DeviceNet input and output devices.
Module (MOD) Status Indicator: This is also a bi-color (red/green) LED indicator that provides information on the status of the 2711P-RN10C module. It shows whether or not the 2711P-RN10C communication module has power and whether it is functioning correctly.
Network (NET) Status Indicator: This indicator is a bi-color (red/green) LED that reports the communication link status between a PanelView Plus 400 or PanelView Plus 600 operator terminal and the DeviceNet devices.

C) 1485C-P1-C600 DeviceNet Round Media

The 1485C-P1-C600 is a DeviceNet Round Media–Thin Cable type–with a spool length of 600 meters (1968 feet). It is designed as the trunk line or drop cable in DeviceNet networks.

This Thin Cable system includes a yellow outer jacket made of Chlorinated Polyethylene (CPE) material, which provides superior chemical resistance. It features a voltage rating of 250 VDC and a maximum current rating of 4 Amperes. It is available with a cable diameter of 6.9 mm (0.27 inch.), and its bend radius is 10x the cable diameter. The 1485C-P1-C600 thin cable is also CSA-certified and UL-listed, with an IP67 environmental rating.