Process Control and Wireless Networks

Industrial plants, factories and process automation systems are increasingly deploying information and communications technologies to facilitate data sharing and analysis in integrated control networks. Despite the harsh process control environment, signal propagation loss and radio frequency (RF) interference, wireless connections provide fast and easy access to a variety of field instruments and reduce network installation costs and ongoing maintenance outlays. This serves as an incentive for the adoption of industrial wireless networks based on industry standards such as ISA100.11a, a wireless networking technology standard developed by the ISA (International Society of Automation) and the WirelessHART, a wireless sensor networking technology based on the Highway Addressable Remote Transducer Protocol (known as HART). Wide-scale adoption proceeds cautiously though, as industrial environments vary widely and process control systems exhibit a multitude of critical wireless networking requirements, such as:
  • Deterministic transmissions in shared wireless bandwidth.
  • Low-cost operation.
  • Long-term durability.
  • High reliability in the harsh radio propagation environment.
Wired connections have proven themselves effective in supporting reliable, point-to-point communications between the controller and the field instruments. A problematic limitation exists with wired connections though - they are unable to accommodate the growing demands and future requirements to support adaptive network topology and rapid reconfiguration encountered in new process control systems.

In lieu of laying down miles of cables to connect hundreds of field instruments, industrial wireless communication networks provide wireless connections with customized network topology, allow for plug-and-play configuration, and offer lower installation and maintenance costs.

Compared with the requirements of standard Internet data services, wireless in the process control environment has stricter quality of service (QoS) requirements. These include more highly reliable transmissions in mobile use cases as well as centralized data analytics, tighter message latency, and lower power consumption.

Hazardous Area Antennas

Gathering information in hazardous areas is critically important for plants to access. Wireless communications is vital for improved efficiencies, real-time monitoring of machinery and equipment, and the safety and well-being of personnel.

Hazardous area antennas from Analynk Wireless are designed and constructed for very rugged industrial applications. Furthermore, all Analynk hazardous area antennas  are UL  listed for Class 1, Groups C & D and have ATEX/IECEx Certification. Finally, a range of frequencies are available from 900MHz, 2.4GHz, Cellular, GPS, Iridium and dual bands.



Adapting Wireless Access Points to Hazardous Areas

Cisco 3602E and Hazardous Enclosure
Cisco 3602E and Hazardous Enclosure
Wireless technologies are not new in industrial process control, and are increasingly used for real-time control and critical applications. One key piece of hardware is the wireless access point (AP). Wireless access points are networking devices that allows a Wi-Fi device to connect to a wired network.

In autonomous architectures, standalone wireless access points are used to implement all WLAN (wireless local area network) functions. They  have to be configured and managed individually and are typically used in smaller installations or stand-alone applications.

Aruba-AP70 and Hazardous Enclosure
Aruba-AP70 and Hazardous Enclosure
Unified architecture (UA) is preferred in large-scale, plant-wide wireless deployments because of its ability to handle a variety of clients and applications. Unified architecture offers guest systems, intrusion protection and facilitates plant-wide mobility. Centralized control and easy configuration are delivered through light-weight access points (LWAP) and wireless LAN controllers (WLC).

Well Known Manufacturers of Access Points


Meru-AP-1020e and Hazardous Enclosure
Meru AP-1020e and Hazardous Enclosure
Cisco Systems, Inc. develops, manufactures and sells networking hardware, and telecommunications equipment. Cisco specializes into specific tech markets, such as Internet of Things (IoT), domain security and energy management.

Miraki72 and Hazardous Enclosure
Miraki MR72 and Hazardous Enclosure
Aruba, a Hewlett Packard Enterprise Company, brings Wi-Fi wireless LAN mobility solutions to enterprise networks. Its core products are wireless Access Points (APs), wired switches, mobility controllers, and network management software.

Meru Networks is a supplier of wireless local area networks (WLANs) to healthcare, enterprise, hospitality, K-12 education, higher education, and other markets.

Zebra-AP7532 and Hazardous Enclosure
Zebra-AP7532 and Hazardous Enclosure
Meraki was acquired by Cisco Systems in December 2012 and is an equipment and tech company who's solutions include wireless, switching, security, EMM, communications, and security cameras, all centrally managed from the web.

Zebra Technologies/Motorola manufactures computer systems that include printing, barcode, communication, mobile computing and advanced data capture communications technologies to the manufacturing supply chain, retail, healthcare and government sectors.

Adapting Access Points for Hazardous Area Use


In industrial facilities, hazardous areas are defined as areas where flammable liquids, gases, vapors or combustible dusts exist in sufficient concentration to produce an explosion or fire. In order to locate access points in hazardous areas, specialized access point enclosures fitted with explosion-proof antennae must be used. These enclosures provide UL listed, Class 1, Division 1, Groups C &; D, Zone 1, ATEX Zone 1 antennas (2.4GHz and 5.0GHz), mountings brackets and hardware.

Analynk, a manufacturer of wireless instrumentation in Columbus, OH, offers a wide variety of hazardous area access point enclosures as well as explosion-proof antennas.  Contact them by visiting https://analynk.com or calling 614-755-5091.

SensaLynk™ Single & Multi-point Wireless Transmitters, Receivers, and Repeaters

The SensaLynk™ line of industrial wireless products are designed to meet today's increasing demands for greater efficiency, higher reliability and lower cost of ownership. SensaLynk™ wireless technology supports industry standards and protocols and maximizes the flexibility of your process control system while reducing inventory and installation costs.

https://analynk.com
(614) 755-5091

HazaLynk™ Wireless Products for Hazardous Areas

The HazaLynk™ Series incorporates a wide selection of wireless hazardous area devices to suit a variety of industrial applications. The product line includes wireless instruments for hazardous areashazardous area antennas, hazardous area access point enclosures, and hazardous area RF enclosures that simplify the process of installing field instrumentation, while meeting code requirements for hazardous classified and explosive environments.

https://analynk.com
(614) 755-5091


Hazardous Area Classifications

Hazardous AreaWhen electrical equipment is used in, around, or near an atmosphere that has flammable gases, vapors, or flammable liquids, there is always a possibility or risk that a fire or explosion might occur. Those areas where the possibility or risk of fire or explosion might occur due to an explosive atmosphere and/or mixture is often called a hazardous (or classified) location/area.

Currently there are two systems used to classify these hazardous areas; the Class/Division system and the Zone system. The Class/Division system is used predominately in the United States, whereas the rest of the world generally uses the Zone system.

Class/Division System

Hazardous locations per the Class/Division system are classified according to the Class, Division, and Group.
  1. Class - The Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere which may or may not be in sufficient quantities.
    • Class I - Locations in which flammable gases or vapors may or may not be in sufficient quantities to produce explosive or ignitable mixtures.
    • Class II - Locations in which combustible dusts (either in suspension, intermittently, or periodically) may or may not be in sufficient quantities to produce explosive or ignitable mixtures.
    • Class III - Locations in which ignitable fibers may or may not be in sufficient quantities to produce explosive or ignitable mixtures.
  2. Division - The Division defines the probability of the hazardous material being able to produce an explosive or ignitable mixture based upon its presence.
    • Division 1 indicates that the hazardous material has a high probability of producing an explosive or ignitable mixture due to it being present continuously, intermittently, or periodically or from the equipment itself under normal operating conditions.
    • Division 2 indicates that the hazardous material has a low probability of producing an explosive or ignitable mixture and is present only during abnormal conditions for a short period of time.
  3. Group - The Group defines the type of hazardous material in the surrounding atmosphere. Groups A, B, C, and Dare for gases (Class I only) while groups E, F, and G are for dusts and flyings (Class II or III).
    • Group A - Atmospheres containing acetylene.
    • Group B - Atmospheres containing a flammable gas, flammable liquid- produced vapor, or combustible liquid- produced vapor. Typical gases include hydrogen, butadiene, ethylene oxide, propylene oxide, and acrolein.
    • Group C - Atmospheres containing a flammable gas, flammable liquid- produced vapor, or combustible liquid- produced vapor. Typical gases include hydrogen sulfide, ethyl either, ethylene, and acetaldehyde.
    • Group D - Atmospheres containing a flammable gas, flammable liquid- produced vapor, or combustible liquid- produced vapor. Typical gases include acetone, ammonia, benzene, butane, ethanol, gasoline, methane, natural gas, naphtha, and propane.

Zone System

Hazardous locations per the Zone system are classified according to its Zone. For gas atmospheres electrical equipment is further divided into Groups and Subgroups.

The Zone defines the probability of the hazardous material (gas), being present in sufficient quantities to produce explosive or ignitable mixtures.
  • Gas
    • Zone 0 - Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time.
    • Zone 1 - Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions.
    • Zone 2 - Ignitable concentrations of flammable gases or vapors which are not likely to occur under normal operating conditions and do so only for a short period of time.
  • Group - Electrical equipment used in gas atmospheres is divided into two groups.
    • Group I - Equipment used in mines with atmospheres containing methane or gases and vapors of equivalent hazard. (Note: Group I does not apply to offshore and is shown for information purposes only).
    • Group II - All other equipment; which is further subdivided into three subgroups.
      • Group IIA - Atmospheres containing propane, or gases and vapors of equivalent hazard.
      • Group IIB - Atmospheres containing ethylene, or gases and vapors of equivalent hazard.
      • Group IIC - Atmospheres containing acetylene or hydrogen, or gases and vapors of equivalent hazard.
Reprinted from The Bureau of Safety and Environmental Enforcement
https://www.bsee.gov

The Move Toward Industrial Wireless Control

wireless instrumentation Demands for safety, reliability, efficiency, and quality put manufacturing plants under tremendous pressure. Unexpected shutdowns and outages have devastating effects on plant performance. Lost production, increased energy costs, unplanned maintenance costs, and augmented safety concerns are outcomes of equipment failure. Tomorrow's technologies must mitigate these process control realities.

Wireless technology is a serious contributor in the effort to improve plant efficiency, lower risk, and increase productivity. Wireless transmitters are available for monitoring virtual all process variables such as pressure, temperature, level, flow, and density. In harsh environments these devices provide critical performance data transmission around the clock.

Wireless instrumentation provides a compelling argument when you consider installation cost savings and convenience.  The cost savings associated with the elimination of wires and cables is estimated to be as high as 70% when compared to the cost using cables for the same application. Furthermore, wireless instruments keep personnel out of hazardous areas, providing additional safety and compliance benefits.

All industries face cost cutting realities as they strive for continuous process improvement.  The need to build a better mousetrap is always present. Before widespread adoption of wireless occurs, concerns about reliability, acclimation, and integration must be overcome. But, as deployment costs are reduced, maintenance costs are reduced, employee safety is improved, and environmental compliance is advanced, wireless instrumentation adoption with continue to accelerate in modern process control installations.