Thursday, August 22, 2019

Applications and Industries Using the ABB LMT Magnetostrictive Level Transmitter


This video outlines the primary industries and applications where the ABB LMT Series of level transmitters are used.

The ABB LMT Series of level transmitters is a modular range of field mounted, advanced microprocessor-based electronic transmitters, utilizing multiple sensor technologies. Accurate and reliable measurement of liquid level and interface are provided in even the most difficult and hazardous  industrial environments. The LMT100 is also available with optional temperature measurement.

For more information on the ABB LMT series, contact Hile Controls of Alabama by calling 800-536-0269 or visit https://hilealabama.com.

Tuesday, July 23, 2019

Understanding Cascade Control Loops

Cascade with feedforward
Cascade with feedforward (image courtesy of Eurotherm).

Cascade control is a technique used to enable processes with long lags to be controlled with the fastest possible response to process disturbances including setpoint changes, while still minimizing the potential for overshoot. This is achieved by controlling a secondary, more responsive process that influences the main process. The main process is controlled using a master PID loop, the output of which is used to determine the setpoint of the secondary process which is controlled by a second PID loop. This second loop is referred to as the slave loop.

Benefits of Cascade Control:
  • Accurate control of load
  • Compensation for process delays
  • Overheating protection
  • Optimum Process response
For example, in the vacuum heat treatment furnace shown below, the workpiece temperature can be controlled using a cascade configuration where the furnace workpiece temperature is used by the master loop and the the heating element temperature is used by the slave loop.

Cascade with feedforward
Vacuum heat treatment furnace
Vacuum heat treatment furnace.
(Image courtesy of Eurotherm)


Feedforward is an option available when using cascade control. It allows either the master PV, master SP or user defined variable to be fed forward so that it directly influences the slave setpoint (see diagram below).This minimizes the amount of work required from the master PID loop.

Master SP/PV feedforward

In this mode the feedforward limits are set directly in the slave loop’s engineering units, which also adjusts the gain of the feedforward path. In the case of PV feedforward this allows the difference between the master and slave PV’s to be limited and is often called “Delta T control”. This is used on reactor vessels and autoclaves to limit temperature gradients, thus minimizing processing time and ensuring consistent product quality.

Process feedforward
Pasteurization
Pasteurization (image courtesy of Eurotherm).


An example where cascade control with feedforward can be used is in pasteurization heat exchangers. The feedforward signal allows the controller to compensate for rapid variations in inlet flow therefore maintaining a stable outlet temperature.

Cascade Control is ideal for:
  • Heat treatment furnaces
  • Vacuum furnaces
  • Autoclaves
  • Semiconductor diffusion
  • Batch reaction vessels
  • Heat exchangers
  • Crystal growth
  • Distillation columns
For more information regarding applying controllers to any process heating application, contact Hile Controls of Alabama. They can be reached by calling 800-536-0269 or visit their web site at https://hilealabama.com.

Reprinted with permission from Eurotherm.

Tuesday, July 9, 2019

Guided Wave Radar vs. Differential Pressure Level Transmitter

An application guide courtesy of Tek-Trol Technology Solutions and Hile Controls of Alabama.

Differential Pressure (DP) transmitters can be traced back to the 1950s. Since then they have served as one the most popular technologies for fluid level measurement and have left their mark in process industry. The application range is vast and varies from chemical, petrochemical, and refineries to electric power generation and more. Over the years, Differential Pressure transmitters have single handedly dominated the worldwide market of process level measurement instruments with the largest sales volume.

Guided Wave Radar is a revolutionary method of liquid level measurement in which high-frequency electromagnetic waves are guided to travel from transmitter to the material to be measured. It works on the principle of Time Domain Reflectrometry (TDR).

This application guide provides a comparison between traditional Differential Pressure Level Transmitters and Guided Wave Radars for liquid level measurement applications by analyzing the features and benefits of both.



Hile Controls of Alabama
https://hilealabama.com
800-536-0269

Sunday, June 30, 2019

US Power Grids, Oil and Gas Industries, and Risk of Hacking


A report released in June, from the security firm Dragos, describes a worrisome development by a hacker group named, “Xenotime” and at least two dangerous oil and gas intrusions and ongoing reconnaissance on United States power grids.

Multiple ICS (Industrial Control Sectors) sectors now face the XENOTIME threat; this means individual verticals – such as oil and gas, manufacturing, or electric – cannot ignore threats to other ICS entities because they are not specifically targeted.

The Dragos researchers have termed this threat proliferation as the world’s most dangerous cyberthreat since an event in 2017 where Xenotime had caused a serious operational outage at a crucial site in the Middle East. 

The fact that concerns cybersecurity experts the most is that this hacking attack was a malware that chose to target the facility safety processes (SIS – safety instrumentation system).

For example, when temperatures in a reactor increase to an unsafe level, an SIS will automatically start a cooling process or immediately close a valve to prevent a safety accident. The SIS safety stems are both hardware and software that combine to protect facilities from life threatening accidents.

At this point, no one is sure who is behind Xenotime. Russia has been connected to one of the critical infrastructure attacks in the Ukraine.  That attack was viewed to be the first hacker related power grid outage.

This is a “Cause for Concern” post that was published by Dragos on June 14, 2019

“While none of the electric utility targeting events has resulted in a known, successful intrusion into victim organizations to date, the persistent attempts, and expansion in scope is cause for definite concern. XENOTIME has successfully compromised several oil and gas environments which demonstrates its ability to do so in other verticals. Specifically, XENOTIME remains one of only four threats (along with ELECTRUM, Sandworm, and the entities responsible for Stuxnet) to execute a deliberate disruptive or destructive attack.

XENOTIME is the only known entity to specifically target safety instrumented systems (SIS) for disruptive or destructive purposes. Electric utility environments are significantly different from oil and gas operations in several aspects, but electric operations still have safety and protection equipment that could be targeted with similar tradecraft. XENOTIME expressing consistent, direct interest in electric utility operations is a cause for deep concern given this adversary’s willingness to compromise process safety – and thus integrity – to fulfill its mission.

XENOTIME’s expansion to another industry vertical is emblematic of an increasingly hostile industrial threat landscape. Most observed XENOTIME activity focuses on initial information gathering and access operations necessary for follow-on ICS intrusion operations. As seen in long-running state-sponsored intrusions into US, UK, and other electric infrastructure, entities are increasingly interested in the fundamentals of ICS operations and displaying all the hallmarks associated with information and access acquisition necessary to conduct future attacks. While Dragos sees no evidence at this time indicating that XENOTIME (or any other activity group, such as ELECTRUM or ALLANITE) is capable of executing a prolonged disruptive or destructive event on electric utility operations, observed activity strongly signals adversary interest in meeting the prerequisites for doing so.”

Thursday, June 20, 2019

The Jordan Mark 75 Sliding Gate Control Valve: Better Control, Lower Total Installed and Operating Cost


Looking for outstanding control and high flow in a small package? Say hello to the Jordan Valve Mark 75 Sliding Gate Control Valve! The wafer style body and the unique Sliding Gate seat design combine to provide accurate control in a very small package. 

Mark 75 Features / Benefits
    Jordan Valve Mark 75 Sliding Gate Control Valve
  • Smaller Envelope Dimensions
  • Save on material cost
  • Save on shipping cost
  • Save on installation cost
Sliding Gate Seat
  • Shorter Stroke = smaller actuators – Save on air
  • Easy maintenance
  • Quiet operation
  • High turndown
Available in a Variety of Materials
  • Carbon Steel, Stainless Steel, Monel, Duplex, Hastelloy, and more
  • Stainless Steel Yoke
  • Namur compliant yoke allows mounting of positioners and other accessories
For more information, contact Hile Controls of Alabama. Call 800-536-0269 or visit https://hilealabama.com.

Wednesday, June 5, 2019

Understanding Guided Wave Radar Transmitters

Guided wave radar transmitter
Guided wave radar
Transmitter (ABB)
Guided wave radar transmitters are widely used across different industries. These devices with their simple installation and trouble-free operations help industrial companies save time and money. They are ideal for a large number of process applications ranging from simple to complex.

How Do Guided Wave Radar Transmitters Work?


Guided wave radar transmitters rely on microwave pulses. Since microwaves are not affected by dust, pressure, temperature variations, and viscosity, this type of transmitter produces highly accurate results. 

A low-energy microwave pulse is sent down a probe, and a part of it is reflected back when the pulse hits the process media. The liquid level is directly proportional to the time-domain reflectometry. The time when the pulse is launched and received back is measured to determine the distance from the surface of the media. 

Types of Guided Wave Radar Level Transmitters


Guided wave radar transmitterGuided wave radar level transmitters are available in different probe configurations. Selecting the right probe is important for successful implementation of the device. While manufacturers offer a range of guided wave radars, most are derived from the three basic probe configurations: single element, twin element, and coaxial.

Single element probe — The single element probe is the most widely used and least efficient device. The device is popular since it is more resistant to the coating of the liquid. 

Twin element probe — The twin element probe is a good, general purpose probe that is generally used in long-range applications. They are ideal in situations where flexible probes are important for successful reading. 

Coaxial probe — The coaxial probe configuration is the most efficient guided wave radar level transmitters. The probes are used in more challenging low-dielectric applications. 

Benefits of Guided Wave Radar Level Transmitters


Guided wave radar level transmitters provide a range of benefits in different applications. The concentration of the measuring signal is strong and clean. This is due to the narrow path of the signal propagation that reduces the chances of impact by stray signals due to obstacles or construction elements inside the tank. 

Another benefit of guided wave radar level transmitters is that they are easy to install. No mounting holes are required to install the device. This results in cost savings for the organization. The waveguide can be formed to follow the tank’s contours or mounted at an angle. 

The device is ideal in situations where an interface measurement is required. The measuring signals can penetrate the medium deeply, resulting in more accurate results. The waveguide technology is suitable for applications where the medium is subjected to heavy vapors, foam, and dust. 

Guided Wave instruments can detect changes in dielectric consents on the boundary of a property. The device can be configured to detect level at both the top and the bottom of a layer of emulsion. 

Industrial Application of Guided Wave Radar


Guided wave radar level transmitters are increasingly being used in process industries. The sensors are used in situations that previously employed ultrasonic, hydrostatics, and capacitance. The accuracy specification of the basic model range is up to ±5mm, while the accuracy of the advanced models is up to ±2mm. 

The device is generally used in industries to take level readings. The readings are used for local indication and visualization in control systems. 

Moreover, guided wave radar level transmitters are also used for managing liquid inventory, determining safety limits, dry run protection, and leak detection. Other applications of guided wave radar level transmitters include communicating low limits to suppliers, automated ordering systems, and streamlining the logistics process. 

Guided radar level measurement is also suitable for bulk solids. The surface type is not restricted to liquids since the reflected waves are guided easily through any medium. Foam formation and turbulent liquid surfaces and different angled surfaces (as is the case with bulk solids) don’t influence the accuracy of the reading.

Selection of Guided Wave Radar Level Transmitters


Selection of guided wave radar level transmitters should be based on the requirements of the task. Generally, the rigid single element probe configuration is ideal for angled installations for flowing liquids. The dual flexible wire probe is suitable for most other common applications. 

A coaxial probe configuration is recommended for liquids that are cleaner with low dielectric constant and with turbulence on the product’s surface. This type of guided wave radar device is also recommended for installations where the probe is near the tank wall or other obstacles. 

Make sure that the device can withstand the range of temperature within the tank. Most GWR devices are rated up to 850 deg F or 450 deg C. You should select a device with added signal strength since this will result in increased reliability and accuracy of the devices. 

Guided wave radar level transmitter with dynamic vapor compensation is recommended where a high level of accuracy is required under a high-pressure environment. The measurement taken from the device can compensate for changes in vapor dielectric, which results in improved accuracy. 

Other factors that should be considered include mounting and proximity. Single probe configuration can be installed almost anywhere. But the single probe configuration can only to apply to specific situations. 

Lastly, the probe length of the device should be of the right length. The length should be according to the measurement rate. This is an important consideration as it can help in ensuring accurate reading with minimum chances of an error. 

Guided Wave radar level transmitters can also be used with an agitator. However, certain things must be considered prior to use the device. The probe must be prevented from contacting the agitator blades. Make sure that you confirm the ability of the probe to withstand the force inside the medium. This is important since turbulent on the surface may decrease the accuracy of the measurement. You can install the device in a bypass chamber or stilling well for an agitated tank.

The consultation with an applications expert is strongly suggested before any specification or application is configured. Doing so will assure a safe and efficient operation.

For more information about guided wave radar level transmitters, contact Hile Controls of Alabama. Call 800-536-0269 or visit https://hilealabama.com.