Showing posts with label wireless network. Show all posts
Showing posts with label wireless network. Show all posts

Wireless Communication Terminology and Definitions

Wireless Communication Terminology and Definitions

Antenna – A device that converts electrical energy into propagating electromagnetic waves or the reverse.

Antenna Polarity – The orientation of the directionality of electromagnetic waves produced by an antenna. Common polarities are vertical, horizontal, and circular. Receive antennas should be oriented such that its polarity matches that of the transmitting antenna polarity.

Bandwidth – The amount of spectrum occupied by a signal. For example, a standard IEEE 802.11g transmission will use a nominal 22 MHz of bandwidth. An IEEE 802.15.4 transmission on which ZigBee, WirelessHART, and ISA100 Wireless are designed will use a nominal 5 MHz of bandwidth.

Carrier – A single frequency sinusoidal signal represented by a vertical line or spike in frequency.

Channel – A term used to identify a physical communications link and includes the characteristics of the entire path of information flow from transmitter to receiver. A channel is defined by electrical and electromagnetic characteristics of the transmission medium such as bandwidth and distortions.

Interference – RF power, typically in the RF band of interest, that disrupts communications by inhibiting the ability of a receiver to decode a transmission. Sources of interference could include anything that radiates electromagnetic (EM) energy such as machinery and undesirable radio devices.

Signal-to-Noise Ratio (SNR) – Ratio of signal power to naturally occurring emissions such as thermal noise and cosmic background radiation. Maximizing SNR is the primary goal of wireless communications.

Signal-to-Noise-And-Interference Ratio (SNIR) – Ratio of signal power to the sum of naturally occurring noise power and interference power. Minimizing the contribution of interference to SNIR is an important goal of a wireless communications system.

Power Decibels – A logarithmic representation of a voltage or power relative to a reference. Power is converted to decibels by the equation 10 P  10log p . The notation dBW and dBm represent power levels relative to 1 Watt and 1 milliwatt, respectively. The notation dB denotes a ratio of two numbers and should not be used to denote power.

Link Budget – Calculations that predict the probability that a transmission will be successfully detected and decoded by the receiver. A link budget will account for transmission power, signal formatting, noise, signal distortions, interference, receiver characteristics, and the link reliability requirements.

Link Margin – The difference in decibels (dB) between the ability of a receiver to successfully receive a transmission and the expected minimum received power. A link margin of 10 dB indicates that a signal could be attenuated by an additional factor of 10 before it can no longer be received. A link margin should accommodate reasonable unexpected attenuations, distortions, and interference not directly addressed by the link budget.

Transmitter – The device responsibility for transmitting information wirelessly.

Transmit Power – the average amount of RF energy per unit power emitted by the transmit antenna. This is typically specified in Watts, dBW, or dBm.

Bit Rate – The average or peak amount of data transmitted during an interval of time. This is represented as bits per second (bps).

Duty Cycle – The percentage at which a transmitter is active.

Modulation – The method by which information is used to modify the behavior of an RF carrier. Different modulations exist such as amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). Digital modulations are discrete versions of the above modulations. Common modulations used in industrial communications include binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), and quadrature amplitude modulation (QAM), among others. Wi-Fi uses a combination of BPSK, QPSK, and QAM depending on channel quality.

Error Control Coding (ECC) – A method to increase reliability of a communications link by adding data redundancy that can detect and correct errors produced by the channel. ECC increases the amount of bandwidth requirements or decreasing the amount of useful information over a channel.

Frequency Hopping (FH) – A process by which the carrier frequency is changed during or between transmissions accordingly to a pre-defined synchronized method. With FH, transmitter and receiver must tune to the same frequency at precisely the same time. FH hopping adds a layer of complexity to a system but also makes interception or disruption of the wireless system more difficult, thereby making the system more reliable.

Spread Spectrum – A process of spreading RF energy beyond what is needed to transmit information for the purpose of improved medium access, better interference immunity, or minimization of signal detection.

Payload – The information being transmitted. The size of the payload factors into transmission duration. All communication systems have a limit to the size of a payload before fragmentation is required. Not all communication systems support fragmentation. At the lowest layers of a communication system, the payload includes all data encoding and framing.

Receiver – The device responsible for decoding incoming transmissions in accordance with an established protocol.

Received Signal Strength Indicator (RSSI) – A measurement of received signal power.

Received Signal Quality Indicator (RSQI) – A measurement of the quality of the received signal

Sensitivity – The minimum signal strength, SNR, or SNIR required by a receiver to decode an incoming transmission.

Adjacent Channel Interference (ACI) – RF energy that is adjacent to the channel containing a desired signal.

Adjacent Channel Rejection (ACR) – The ability of the receiver to suppress ACI.

Dynamic Range – The difference between the maximum and minimum received signal power. A large dynamic range is particularly helpful in accommodating strong ACI that leaks past RF filtering.

Selectivity – The ability of a device to decode a transmission on one frequency without interference from transmissions on other frequencies.

Reprinted from Guide to Industrial Wireless Systems Deployments by the National Institute of Standards and Technology.

Analynk Wireless
(614) 755-5091

Wireless Process Instrumentation and Cloud-based Solutions

Wireless technologies and cloud computing systems are changing industrial communications. Industrial wireless networks and cloud-based tools, simply stated, allow manufacturing plants to do more with fewer people.

This two-part article delves into the recent trends in the use of cloud-based tools and wireless networks to help plant operators improve their application validation, improve their diagnostic selection of instrumentation, and improve device commissioning.

The benefits of wireless and mobile communications is clear. Engineers and other factory personnel can input data wirelessly via a smart phone, or a laptop computer so they can have their specific requirements recorded. Collaboration with other team members is possible, through the cloud, to determine the optimum set up for the project devices to streamline engineering decisions (and to avoid expensive mistakes upfront in the project). Information in the cloud may also be equipped for instant duplication, so projects that have many identical device configurations can be rapidly repeated.

Using a cloud-based and wireless network approach improves success in installing large numbers of new field instruments, which is common for unit expansion. Other benefits of adapting cloud-based services and wireless networks for prices control include:
  • A convenient way to share and collaborate in real-time. Multiple users can visualize the transmitter configuration though a link. This saves staff time and reduces travel time for support people. 
  • If a beginning user has an underdeveloped knowledge of the application, the cloud can provide readily accessible information such as compatibility charts, specification sheets, code requirements, etc … . 
  • Generation of a standard data sheet so engineers don't have to spend as much time on data entry. The data sheet can be stored to support the user's necessary documentation and audit trail. 

The paradigm for instrumentation setup is changing dramatically. Cloud-based tools and wireless communications are optimizing manufacturing operations and delivering capital projects cost effectively, efficiently, and as rapidly as possible.

Under increasing pressure for improved quality, safety, and profits companies are migrating toward cloud-based application, data storage and wireless networking. These new technologies are playing a key role in improving safety, lowering operating costs, providing real-time performance data, and continuously monitor processes.

Glossary of Terms in Wireless Networks in Process Control

Below is a list of terminology, abbreviations, and acronyms used in wireless network technology applied to process control.
  • 6LoWPAN
    • IPv6 Low power Wireless Personal Area Networks
  • ARPA 
    • Advanced Research Projects Agency 
    • Refers to Aruba Wireless Networks, now a Hewlett Packard Enterprise company.
  • BLIP 
    • Berkeley Low-power IP stack
  • CAP 
    • Contention Access Period
  • CFP 
    • Contention Free Period
    • A company that develops, manufactures and sells networking equipment.
  • CSMA-CA 
    • Carrier Sense Multiple Access with Collision Avoidance
  • DAO 
    • Destination Advertisement Objects
  • DIO 
    • DAG Information Object
  • DIS 
    • DAG Information Solicitation
  • DODAG 
    • Destination Oriented Directed Acyclic Graph 
  • DSN 
    • Distributed Sensor Network
  • ETX 
    • Expected Transmission count
  • GTS 
    • Guaranteed Time Slot
  • HBN 
    • Hydrobionet
  • ICMP 
    • Internet Control Message Protocol
  • LLN 
    • Low power Lossy Networks
  • MAC 
    • Media Access Control
  • MBR 
    • Membrane Bioreactor
  • MEM 
    • Micro electromechanical
  • MERU
    • Refers to Meru Networks, a supplier of wireless local area networks (WLANs).
    • A company that designed and sold wireless network equipment.
  • MRHOF 
    • Minimum Rank Objective Function with Hysteresis
  • NCS 
    • Network Controlled System 
  • OF 
    • Objective Functions
  • OS 
    • Operating System
  • PID 
    • Proportional-integral-derivative controller
  • PRR 
    • Packet Reception Ratio
    • Device that takes an existing signal from a wireless router or wireless access point for rebroadcasting.
  • RPL 
    • Routing Protocol for Low-Power and Lossy Networks 
  • RSSI 
    • Received Signal Strength Indication
  • WBN 
    • Wireless Biosensor & Actuator Network 
  • WIFI
    • Technology for radio wireless local area networking of devices based on the IEEE 802.11 standards.
  • WINS 
    • Wireless Integrated Network Sensors
    •  A networking device that allows a Wi-Fi device to connect to a wired network to create a second network.
  • WSN 
    • Wireless Sensor Network
    • Popular, low-cost, low-power wireless mesh networking standard.
  • Z-WAVE 
    • Tightly controlled mesh network that caters to the smart home and smart building space.

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.

Analynk Expands Offering of Wireless Access Point Enclosures For Hazardous Areas

industrial wireless access point enclosure
Industrial Wireless Access Point Enclosure For
Hazardous Area
Analynk Wireless has developed a range of industrial wireless communications products suitable for use in hazardous areas. One product line, Hazalynk, includes enclosures for wireless access points that can be installed in hazardous areas. The company has recognized the special adaptations needed for installing wireless access points within hazardous areas in industrial process settings, and tailored the products to show their recognition of the needs of those responsible for providing industrial wireless communications in these specialized zones.

The Hazardous Area Access Point Enclosures are designed to accommodate the customer's selected access point device. Preconfigured models accommodate units from Cisco, Symbol, Meru, Aruba, Hewlett Packard, Motorola, and other brands. Custom arrangements are possible to accommodate most brands and models.

The matching enclosure for an access point will have:
  • Custom mounting bracket mating to the customer's access point.
  • UL listed enclosure for subject hazardous area, including antenna locations coordinated with access point device arrangement.
  • UL listed explosion proof antenna, one or more as need for the subject access point.
  • All hardware, mounting plate, and RF cables to simplify installation and startup
A product specialist can help you with the latest available information. Contact them to discuss your application and how to best fulfill your hazardous area wireless communication requirement. Watch the short video.

Out of the Box Thinking Delivers Benefits with Industrial Wireless Test Station

Industrial Tire
Tire manufacturer used wireless technology
to improve output
Wireless network communication has enjoyed continuously increasing rates of adoption in the industrial process control field for a number of years. Protocols and methodologies are generally well established and a wide range of products are available, making it less challenging to configure an application solution. As the manufacturers of industrial wireless devices have gained production efficiency and responded to an increasingly competitive market, the cost of implementing a wireless solution has become less of a barrier. Truly, industry is now in a phase where creativity and ingenuity will bring changes to traditional process and production operations to take full advantage of the untethering of many common measurement and control devices.

Traditionally, most measurement and control instrumentation was fixed in place by piping or cabling. While that is still the case throughout much of the industrial sector, opportunities are continuously emerging for wireless technology to provide improvement in performance and efficiency. I came across an example of how one manufacturer of tubeless tires devised a wireless test station to replace their existing wired version to:

  • Reduce maintenance by eliminating signal cables and power cables. No more cable damage from moving wired transmitters around the tire test area. 
  • Replace manual data logging with remote automatic data logging. 
  • Maintain or increase the accuracy of each measurement point. 
  • Allow a single test station to be employed easily at multiple locations throughout the factory. 

This was accomplished using readily available pressure transmitters, wireless transmitters, access points, receivers, and related hardware to provide a complete measurement system delivering test and measurement data to a remotely located data logger.

Use your creativity, your ingenuity. Get outside the box and examine your industrial process or production operation. Look for opportunities to sharpen your efficiency and improve outcomes. The prospects are good that there may be more gained from a wireless installation than the mere absence of cabling. Discuss your ideas with a wireless product manufacturer, solicit their recommendations, and evaluate the potential benefits to your operation.

Explanation of Explosion Proof Enclosures

Explosion Proof Access Point Enclosure
Explosion Proof
Access Point
This is a short video that explains what an explosion-proof enclosure is, what defines it as “explosion-proof”, and the principle behind why its safe to use in explosive or combustible atmospheres.

“Explosion-proof" doesn't mean the enclosure can withstand the forces of an external explosion. It means that the enclosure is designed to cool any escaping hot gases (caused by an internal ignition) sufficiently enough as to prevent the ignition of combustible gases or dusts in the surrounding area.

Analynk provides hazardous area wireless access point enclosures are designed and certified for use in hazardous locations. For more information, contact:

Analynk Wireless, LLC
790 Cross Pointe Road
Columbus, OH 43230
614-755-5091 phone
614 -755-5093 fax

Hazardous Area Access Point Enclosures for Explosive Atmospheres

Hazardous area wireless access point enclosures are designed and certified for use in hazardous locations such as chemical plants, refineries, oil & gas platforms, mining facilities, grain processing, and plastics processing. These enclosures also provide an additional level of security for your wireless access point by preventing tampering, vandalism, and theft.

Industrial wireless access point enclosures designed for Class 1, Division 1, Hazardous Locations, Groups C & D, ATEX Zone 1. Available for Symbol, Cisco, Meru, Aruba, HP, and Motorola access points.
  • Designed for Class 1, Division 1,  Hazardous Locations 
  • 802.11 b/g 
  • Available for Symbol, Cisco, Meru, Aruba, HP, and Motorola access points 
  • Explosion proof antennas 
  • ATEX certification for Explosion Proof enclosure and antennas available