Fresnel Zones and Industrial Wireless Connections

Industrial wireless connections established outdoors across
long distances have to consider transmission path geometry.

A Fresnel zone, of which there an infinite theoretical number, is an ellipsoid shaped area extending between radio signal transmission and receiving antennas. Having a basic understanding of their impact on successful implementation of a lengthy wireless process signal connection will prove useful.

Wireless transmission of process signals in industrial settings becomes more prevalent every year, and should continue to do so for quite some time. Many installations are part of networks operating similarly to the wifi you may have in your home, with multiple points communicating via a network control scheme of some sort. The facility is flooded with signal coverage through multiple access points, so there may not be much need to consider signal propagation. This is an oversimplification, but as an operator or implementer, making the actual signal connection is probably not going to be an issue in most cases.

What about the other cases?

Antennas with three Fresnel zones depicted and
obstruction that is outside the primary Fresnel zone
Courtesy Wikipedia

An extended transmission distance across an outdoor area requires more understanding of signal propagation and factors that impede successful delivery of process data from transmitter to receiver. One concept that comes into play is the Fresnel zone.

Let's avoid an overly technical approach to Fresnel zones. The purpose of this post is to provide those with limited radio expertise familiarity with the subject of Fresnel zones at a level enabling visualization of the concept, and also to recognize its potential impact on achieving a successful wireless process connection.

We often consider the transmission path between two points to be the familiar "line of sight", an unobstructed straight line between transmitter and receiver. In practice, radio frequency transmission is more accurately characterized by Fresnel zones. Being aware of the shape of the first, or primary, Fresnel zone for your application is an important element in identifying potential obstructions. A general practice is to keep the primary Fresnel zone at least 60% clear of signal obstructions, in order to maintain high wireless link performance.

There are numerous sources of Fresnel zone calculators online, but a strong recommendation to consult with your selected wireless equipment provider is in order here. Combine their expertise at applying their products with your application knowledge to leverage an effective solution.

Expand Industrial Wireless I/O Capacity With A16000

The A16000 increases the I/O capacity of a dedicated
transmitter and receiver.

Modern industrial radio frequency (RF) communications gear enables the establishment of process signal connections across very small or very large distances. The advantages of implementing cost effective connections within a very short time frame makes wireless connections a popular option in industrial settings. A misconception arises, from time to time, that it is necessary to have a dedicated transmitter and receiver for each process signal. Analynk has a solution that provides for delivery of up to sixteen process signals over a single transmission path.

Analynk provides hardware that easily allows the transmission and reception of up to 16 I/O points using single transmission and reception point devices. The A16000 Expansion Module can be configured with up to four internal cards that accommodate various types of input and output signals. The configuration process is similar to setting up the I/O on a PLC. Connect the process signals to the A16000, and the A16000 to one of Analynk's transmitter or receiver devices. Setup is straight forward and allows the installation to be operable in a very short time frame. The A16000 can also be used to expand existing installations as process I/O points increase.

Share your wireless communications and signal transmission challenges with the experts at Analynk and get recommendations on how to best implement workable solutions.

Analynk Model A16000 RF Expansion Module from Analynk Wireless, LLC

Hazardous Area Wireless Access Point Enclosure for Aruba AP 274

This version of the AP617 Hazardous Area Wireless Access
Point Enclosure accommodates six explosion proof antennas.

The Aruba AP-274 wireless access point carries a description of it's operating environment range that says "Purpose-built to survive in the harshest outdoor environments, 270 series APs withstand exposure to extreme high and low temperatures, persistent moisture and precipitation, and are fully sealed to keep out airborne contaminants. All electrical interfaces include industrial strength surge protection." While the access point can withstand outdoor environments, maybe even some industrial environments, there is a large class of industrial settings where it is just as important to protect the environment from the device as it is to protect the device from the environment. Hazardous atmospheres require isolation and special housing of electrical gear that have potential to be source of ignition.

Analynk manufactures enclosures for industrial wireless access points, facilitating their installation in hazardous locations. Each access point enclosure is specifically targeted and designed to provide easy installation of specific wireless access points from a range of manufacturers. Every model is provided with UL listed explosion proof antennas, a mounting bracket designed for the target access point, and RF cables to make the antenna connections. Enclosures have penetrations specifically located to accommodate the target access point.The current offering accommodates a range of units from Symbol, Cisco, Meru, Aruba, HP, and Motorola, with more models added regularly to accommodate additional wireless access points.

The website has a newly added data sheet for the AP617, specifically designed for the Aruba AP-274 dual band access point. Analynk Wireless specializes in industrial wireless communications. Your wireless communication challenges are welcome at Analynk, so make contact and share your application requirements. Combining your own knowledge and experience with Analynk's industrial wireless application expertise will produce an effective solution.

The new datasheet for the AP617 is provided below. You can see all the models and their companion access points on the Analynk site.

AP 617 Hazardous Area Wireless Access Point Enclosure from Analynk Wireless, LLC

Load Cells in Process Measurement

Strain gauges and load cells are found throughout
industrial processing applications.

In industrial application of process measurement and control, principles of the physical sciences are combined with technology and engineering to create devices essential to modern high speed, high accuracy system operation. Years of research, development, and the forward march of humanity’s quest for scientific knowledge and understanding yield packaged devices for process measurement that are easily applied by system designers and operators.

Load cells are the key components applied to weighing component or processed materials in modern processing. They are utilized throughout many industries related to process management, or just simple weighing operations. In application, a load cell can be adapted for measurement of items from the very small to the very large.

In essence, a load cell is a measurement tool which functions as a transducer, predictably converting force into a unit of measurable electrical output. While many types of load cells are available, the most popular cell in multiple industries is a strain gauge based cell. These strain gauge cells typically function with an accuracy range between 0.03% and 0.25%. Pneumatically based load cells are ideal for situations requiring intrinsic safety and optimal hygiene and, for locations without a power grid, there are even hydraulic load cells, which function without need for a power supply. These different types of load cells follow the same principle of operation: a force acts upon the cell (typically the weight of material or an object) which is then returned as a change in a reference value. Processing the value yields an indication of weight in engineering units. For strain gauge cells, the principle of deformation applies, where extremely small amounts of deformation, directly related to the stress or strain being applied to the cell, are output as an electrical signal with value proportional to the load applied to the cell. The operating principle allows for development of devices delivering accurate, precise measurements of a wide range of industrial products. Advantages of load cells include their longevity, accuracy, and adaptability to many applications, all of which contribute to their usefulness in so many industries and applications.

Analynk manufactures process measurement and control equipment that utilizes strain gauges in their operation, as well as signal alarms and transmitters that will convert strain gauge output signals into common process control signals. Equipment for further establishing wireless connections among measurement and control devices is a specialty of Analynk Wireless. Share your process measurement and connectivity challenges with the industrial wireless experts at Analynk, leveraging your own process knowledge and experience with their specialized application expertise to develop effective solutions.

Wireless Access Point Enclosures for Hazardous Areas

One of  many variants of access point enclosures for
hazardous areas

Wireless access point enclosures for use in areas classified as hazardous are designed and certified for use in those locations within chemical plants, refineries, oil and gas platforms, mining facilities, grain processing, plastics processing and more. These specialized enclosures also provide an additional level of security for wireless access point by preventing tampering, vandalism, and theft.

It can be advantageous for the wireless network gear in the processing or manufacturing section of a facility to conform to certain information technology standards established for the larger scope of the organization. There can be real benefits to standardizing on particular brands or types of hardware. The tasks involved with back end management of network infrastructure are less complex when all the equipment is of the same vendor and product family. Provisioning, which includes initial setup, long term management, and unit loss management, is simplified when all the units are the same. Process engineers and operators pursue the same goal in standardizing on particular transmitters, valves, or other components that have multiple installations throughout a facility. Difficulty can arise when the IT team's chosen wireless access point needs to be installed in an area classified as hazardous due to the potential for ignition of flammable or explosive gases and vapors.

Analynk's industrial wireless access point enclosures are designed for Class 1, Division 1, Hazardous Locations, Groups C & D, ATEX Zone 1. Standard models are available to accommodate Symbol, Cisco, Meru, Aruba, HP, and Motorola access points. Each unit arrives with an enclosure fitted with mounting holes for the required antenna set and cabling, custom interior mounting plate for the designated access point, explosion proof antenna set and cables to connect the antenna set to the access point. Analynk's hazardous area enclosures for wireless access points deliver a ready-made solution for installing wireless access points in hazardous locations.

Analynk Completes 15 Years of Product Innovation

Analynk completed 15 years of successful wireless equipment
innovation and manufacture.

Analynk Wireless, LLC just completed its fifteenth year of operations, designing and manufacturing wireless comunications devices for use in the process control arena. Their simple to use and effective wireless devices can be combined with the company's Telmar line of wired process measurement and control instruments, or combined with instruments and equipment of the customer's choosing, to establish process connections across almost any distance.

Steady innovation and improvement, coupled with curiosity and a genuine desire to help customers meet the challenges of process measurement and control, have contributed greatly to the success of the company. New product versions, as well as expanded options, come in an almost continuous stream as Analynk innovates to meet customer application requests.

Share your process connectivity challenges with the experts at Analynk Wireless, leveraging your own process knowledge and experience with their industrial wireless expertise.

Off The Grid Wireless Communication for Process Measurement and Control

The Analynk preconfigured combination solar and battery
power unit enables simple off the grid implementation.

Remote process stations of almost any type requiring monitoring and transmission of measurement data can be accommodated easily with Analynk's solar power unit. The compact preconfigured unit needs just a selection of process measurement gear and a wireless transmitter to enable simple installation. Analynk has already done the design and assembly. The user installs their measurement gear and an Analynk transmitter, performs a quick setup operation, and the station is up and running.

In addition to the obvious advantage of enabling process measurement and transmission where power is not available, there may be instances where a wireless solution saves time and expense of extending a power circuit to the instrument location. The power supply unit comes complete with solar panel, battery, charge controller, and NEMA 4 enclosure. Options are available to accommodate specific installation requirements and custom units can be assembled for larger power requirements and other special applications.

The data sheet below provides more detail. Share your wireless process measurement and control connectivity challenges with Analynk for effective solutions.

Solar power supply for industrial wireless transmitters from Analynk Wireless, LLC