Industrial Networking

The challenge with industrial controls as well as with other electronic devices intended for use in industrial environments is to have them function reliably in spite of adverse conditions... 

Industrial environments present much harsher conditions than are found in typical office environments. They not only often have extremes of temperatures, humidity, dirt, and corrosive materials, they may also contain devices such as motors and mechanical switches, which cause a large amount of electromagnetic interference (EMI).
The challenge with industrial controls as well as with other electronic devices intended for use in these environments is to have them function reliably in spite of adverse conditions. This may mean using a device that’s built to withstand harsh conditions, protecting the device in a specialized cabinet, or both. Industrial networking solutions are suitable for use in:

• Agriculture
• Military applications
• Factory environments
• Manufacturing
• Oil/gas drilling and mining
• Public utilities
• Traffic control
• Transportation

Extended temperature range

Many industrial devices are installed outdoors in unventilated sealed enclosures, which freeze in the winter and heat to extremely high temperatures in the summer. They and their power supplies are expected to perform over a wide temperature range. Typically they’re rated so you can select one appropriate toyour environment. Operating temperature tolerances are defined as:
• Standard: 0° to +40° C (32° to 104° F)
• Hardened: -25° to 60° C (-13° to +140° F)

  • Extreme: -40° C to +75° C (-40° to +167° F)
    Because industrial components are sealed against contaminants and also because they’re often installed inside enclosures, they rely on air convection rather than fans for cooling.


    Mounting

     Components for office or data center use are usually either freestanding or mounted on 19″ rails in a cabinet or rack. Industrial devices, on the other hand, are usually panel mounted by bolting them to a flat surface, or they may be DIN rail mounted. DIN rail is an industry-standard metal rail that is used both wall-mounted and rack-mounted. Industrial devices mount directly on the rail or may come with separate DIN rail brackets.

Power supplies

The power supplied to industrial sites can vary tremendously. AC power varies anywhere from 60 VAC to 960 VAC, and often only DC power is supplied, with 24 VDC or 48 VDC being common. Industrial power may be three-phase power, which is used for power transmission across power grids and is favored for large motors and heavy loads at industrial site. It’s also frequently “dirty” power, subject to noise, voltage fluctuations, and spikes. This inconsistent power is hard on the electronic components in industrial devices and can cause equipment damage or data loss.

Because of this variability, industrial control devices are either sold entirely separately from their power supply or are available with a choice of power supplies. Unlike ordinary networking devices, industrial controls require you to choose the correct power supply for both device and application. Industrial power supplies must be matched to both the type of power input they’ll be receiving from the power grid and the power output they’ll be expected to provide to the industrial control device.

EMI protection

Industrial areas are also prone to electromagnetic interference (EMI) and radio-frequency interference (RFI). Interference and noise from EMI/RFI creates unwanted signals that may interfere with network performance.

Devices for industrial applications are usually built to withstand higher EMI than those intended for office or data center use. Chassis are usually shielded, and EMI signals can be absorbed by using capacitor-based circuits or through special coatings as well. Resistance to moisture and contaminants Moisture is the enemy of electronic components, and industrial devices are often subject to water in all its forms, from high humidity and condensation to drips and splashes. Industrial devices are also often subject to dirt, dust, oil, salt spray, and chemicals when they’re installed outdoors or indoors in an environment such as a factory floor.

For these reasons, industrial components are usually housed in hardened metal cases that are sealed against contaminants, including particulates such as airborne dust, as well as moisture, and sometimes chemicals. One way to protect industrial devices from their environment is with an enclosure designed to seal out contaminants such as dust and moisture. These enclosures are usually NEMA rated to describe the amount of protection they provide.

Ingress protection ratings

Once limited to networks in office environments, Ethernet has also proven to be a robust alternative to the RS-232 interfaces traditionally used with industrial devices such as programmable logic controllers. Ethernet brings speed, versatility, and cost savings to industrial environments. The requirements of industrial environments are different from those of offices, and there have been a proliferation of industrial standards. The most commonly accepted are the Ingress Protection (IP) ratings developed by the European Committee for Electro technical Standardization (CENELEC), which specify the environmental protection an enclosure provides. IP ratings consist of two or three numbers. The first number refers to protection from solid objects or materials; the second number refers to protection from liquids and the third number, commonly omitted from the rating, refers to protection against mechanical impacts.

An IP67 rating means that the connector is totally protected from dust and is protected from the effects of immersion in 15 centimeters to 1 meter of water for 30 minutes.

Security and Surveillance
Keeping an eye on things

Protect your property and assets, and ensure the safety of employees, with a security and surveillance system. Whether you have one building or a large campus, implementing a security network might be easier than you think — especially if you don’t have to run all new cabling.

In this campus scenario, the security surveillance system combines new and existing technologies and cabling.

  • The operations center houses the data center and security command center.
  • When first built, the guard station had an analog phone, which was connected to the operations center via twisted-pair cabling. As technology evolved, new security requirements mandated that the guard station include a PC, security camera, and an IP phone. To achieve this, the company could have trenched a new fiber cable to the guard station for IP connectivity, but opted instead for a much faster and much more economical route. They decided to deploy a pair of LB300 Series EthernetExtenders (page H26) over the existing twisted-pair cabling. The basement of the operations center building houses the company’s security center. The company wanted to mount IP security cameras on the roof of the building. Because the cameras would be more than 300 feet from the security center, the company decided to run fiber to the cameras. To convert the fiber to copper CAT6 cable and to power the cameras, the company installed LEH1000 Series Hardened PoE Switches
  • Fiber cable was trenched to connect the operations center to the company’s second building.
  • The company recently upgraded its parking lot security cameras from analog to digital. The old analog cameras were connected via coax cable. To provide IP connectivity to the new digital cameras over the existing coax cable and to eliminate costly fiber trenching and disruption, the company used the multidrop Industrial LB532 Series Ethernet Extenders
  • While upgrading its rooftop security cameras, the company also added a security camera to the electrical/generator building. As there was no IP connection between the buildings, the company decided to use a pair of LWE200 Series 5-GHz Wireless Ethernet Extenders with PoE to connect the cameras.

Analog cameras vs. IP cameras

An analog camera is a traditional CCTV camera. It sends video over coax or UTP cable to a digital video recorder (DVR). While analog cameras perform well, they are limited to resolutions of the NTSC/PAL standards of 720 × 575 pixels or 0.4 megapixel. Analog camera resolutions range from 420 to 700, which at the high end can produce sharp images. IP cameras are digital cameras. One of the biggest advantages of IP cameras is their resolution that can range from 1.3 megapixels to 5 megapixels (2592 x 1944) or above. Generally, IP cameras give resolutions 6 to 20 times higher than analog cameras. IP cameras traditionally provide better zoom-in images than analog cameras as well.In addition, most IP cameras are intelligent and can perform additional security tasks, such as sending a message when they detect motion. Many systems today are hybrid systems incorporating both analog and IP cameras.

Extender Ethernet connections over existing twisted pair.

Black Box LB532A Series Industrial Ethernet Extenders, G-SHDSL

• Extends industrial 10/100BASE-TX Ethernet connections at speeds up to 5.7 Mbps.
• Use to connect industrial Ethernet devices and remote LANs up to 6.9 km apart.
• Use as a repeater in multi-drop applications.
• Tough—meets IP40 specs and withstands temperatures of -40° to 85° C.
• Includes a built-in, four-port, autosensing 10-/100-BASE-TX switch.

      

The scalable switch you can customize with copper and fiber ports.

Black Box LE2700 Series Hardened Managed Modular Switch

• Scalable, flexible, cost-effective modular design enables you to add capacity as demand increases.
• Modular Chassis supports 10/100/1000BASE-T, 100/1000-Mbps SFP, 100-Mbps SC/ST, or 10-GbE SFP+ modules.
• Choose from 4- and 8-port switch modules.
• Optional SFP/SFP+ modules for choice of fiber ranges and speed.
• Withstands extreme temperatures of -40 to +185° F (-40 to +85°C).

Built tough

The LE2700 Series Hardened Managed Modular Switch system is designed for demanding applications such as:
• Oil/gas well and pipeline control and monitoring.
• Municipalities for public safety and traffic control.
• Security and surveillance providers for backhauling IP camera video and alarms.
• Utilities, including electric substations and water/waste water.
• SCADA/PLC/M2M systems for remote/automated communications.
• HVAC systems remote control and monitoring.

Scalable, flexible, cost-effective

This switch system is more than just tough. It’s extremely versatile with a range of interface options. The modular design gives you the ability to add the right quantity, speed, and type of interfaces you need. If your needs change in the future, you can just swap out modules. Choose from copper and fiber modules, including a 10-GbE SFP+ module.

Ensure 100% uptime

With dual power supplies, the switch is designed for redundancy. Set it up in a ring topology. If a link fails, the switch automatically falls over in less than 30 milliseconds. The switch is also compatible with redundant switches from other manufacturers.

Very manageable

This switch includes extensive management software enabling you to manage it locally or remotely eliminating costly and time-consuming truck rolls. Software includes: SNMP, QoS, VLAN, IGMP Snooping, DHCP, MSTP, and more.

SFP customization

By plugging in different SFPs, you can customize the switch to the distances and connectors you need. Use the LFP400 Series SFP transceivers with all modules except the LE2731C. Use the SFP+ transceivers (LSP420 Series) with the 10-GbE module (LE2731C).

Keep Network Traffic Flowing

Spanning Tree and Alpha-Ring

Spanning Tree Protocol (STP)

The Spanning Tree Protocol (standardized as IEEE 802.1d) specifies a network design with redundant links to provide automatic backup paths if an active link fails. STP also avoids the creation of bridge loops that cause broadcast storms. Without STP, Ethernet switches with redundant links have no standardized way to keep from looping data over and over again to the other switches in the network, eventually disabling the network’s ability to pass data. The idea behind a Spanning Tree topology is to enable switches to automatically discover a subset of the network topology that is loopfree, i.e., a tree. With STP turned on, the switches will perform the spanning tree algorithm when they are first connected, as well as any time there is a topology change, and automatically communicate with each other in a loop-free mode. Then, should a failure of one of the active links occur, STP unblocks the redundant links to enable the network to continue transmitting traffic.

The Alpha-Ring Protocol

The Alpha-Ring protocol is a proprietary protocol designed to provide a faster network recovery time after a failure than standard STP. As the name suggests, Alpha-Ring enables the switches to be organized in a ring arrangement. During normal operation, the backup path for the Alpha-Ring is blocked, and data follows the other links around the ring. If, however, one of the active links fails, the Alpha-Ring protocol unblocks the backup path to enable data to keep flowing. Typical failover for Alpha-Ring protocol is less than 30 milliseconds. In addition, unlike STP, Alpha-Ring does not operate using any bandwidth-consuming packets to check the ring status. The ring port connections are monitored by each switch individually without the need for test packets to be generated and transmitted around the ring.

Ethernet Ring Protocols

Although Ethernet is usually thought of as having a star or bus topology, it’s also possible to build an Ethernet network as a ring. This configuration has the advantage of providing a redundant pathway if a link goes down. A ring topology is often used in applications such as traffic signals and surveillance where long distances may make it difficult to run links in a star formation from a central switch and where downtime must be limited.

Generally speaking, ring architectures have these advantages:

1. They have fast failover times, typically sub-50ms.
2. They require a decreased number of ports. Fewer ports are needed to provide the same amount of resiliency as            centralized switched networks with redundant paths. This results in decreased initial investment and lower ongoing           maintenance costs.
3. They are scalable and enable a step-by-step network rollout. More switches can be added to the ring incrementally.       The full traffic does not need to traverse a main/distribution switch.
4. They use bandwidth efficiently; dedicated paths are not required.
5. They simplify configuration. Predefined paths between the switches that are connected to the ring are not needed.


Priyanka Kharkar
Marketing Executive – India
Black Box Network Services

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