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Instrumentation refers to the tools or means by which investigators attempt to measure variables or items of
interest in the data-collection process. It is related not only to
instrument design, selection, construction, and assessment, but
also the to conditions under which the designated instruments are administered—the instrument is the device
used by investigators for collecting data. In addition, during the
process of data collection, investigators might
fail to recognize that changes in the calibration of the measuring instrument(s) can lead to biased results.
Therefore, instrumentation is also a specific term with respect to a threat to internal validity in research.
This entry discusses instrumentation in relation to the data-collection process, internal validity, and
research designs.


Positioners usually mount to the control valve actuator and connect
mechanically to the valve stem for position indication. A positioner
is a type of air relay, which acts to overcome hysteresis,
packing box friction, and effects of pressure drop across the valve.

It assures exact positioning of the valve stem and provides finer control.
There are many types of positioners. The basic principles of operation are similar
for all types. The instrument pressure (from an I/P, for example)
acts on the input module, which controls the flapper-nozzle system of the relay.
Supply pressure applies to the relay and the output
pressure of the relay goes to the control
valve actuator.


Most positioners can set up and function for direct
or reverse action. For a direct-acting positioner, increasing the instrument pressure
causes the input module to pivot the beam. The beam pivots the flapper and restricts the nozzle.
The nozzle pressure increases and causes the relay assembly to
increase output pressure to the actuator.

With a direct-acting actuator, the increased pressure moves the actuator stem downward.
The positioner connects mechanically to the stem of the valve.
Stem movement feeds back to the beam by means of a feedback lever and range spring,
which causes the flapper to pivot slightly away from the nozzle to
prevent further increase in relay output pressure.
Note that some positioners accept a milliamp input and include an integral I/P transducer.
The last component in the final control subsystem is the final control element.



Let's look at control valves (Other final control elements include
servo valves, heaters, conveyors, auger feeds, and hopper gates.).
There are many different types, sizes, and applications for control valves.
Selecting the correct control valve for a specific application is crucial to proper
system performance. Under sizing and over sizing are common problems.
There are many valuable resources available to assist with proper selection, not the least of which is a
control valve sales engineer. Here's a typical
control valve. The pneumatic signal from the positioner (or I/P if a positioner is not used)
applies directly to the actuator. For this control valve, the air enters above the diaphragm and pushes against spring pressure to close the
valve.


The valve fully closes when the plug seats tightly against the seat ring.
As air pressure decreases, the spring pressure causes the diaphragm, stem, and plug to move upward,
opening the valve. This means a loss of pressure would cause the valve to open. This is a fail-open valve.
Different configurations of air inlet, spring location, and valve seat
arrangement result in different fail positions and determine whether the valve is direct- or
reverse-acting. For example, this same valve, with the plug below the seat ring (reverse-seated), would open with increased air pressure and would fail closed on loss of
air pressure.


So, all components in the final control subsystem must be configured correctly for the system to work properly.
The fail-safe positions must be correct for the application, and the action must produce
the desired results. These configurations must be properly documented and
utilized during calibration, loop checks, or troubleshooting.
The figure below shows the setup for a bench calibration of an I/P transducer.
The air supply connected to the input must be in accordance with manufacturer's
specification (typically between 20-100 psig).
The pressure standard connects to the air
outlet, and a mA simulator connects to the current
input. It is important for the I/P transducer to be oriented the same way as the installed position in the
field. A change in orientation will introduce error in most
I/P transducers.


If the calibration takes place in the field, one uses the existing supply air.
It is convenient to tee into the air outlet so
one can check the control valve position at the same time.
Of course, you need to ensure the system is in a safe condition before
you open and close the valve. Once the setup is established, apply the mA inputs for each desired test point, such as 4.0, 8.0, 12.0, 16.0, and 20.0 mA.
Record the corresponding outlet pressure at each test point.
3-15 psig output I/P, the corresponding outputs would be 3.0,
6.0, 9.0, 12.0, and 15.0 psig. Some facilities adjust the 0% test point so a slightly higher mA input results in the
0% output. For example, 4.10 mA may result in a 3.0 psig output.




This ensures the valve is in the closed state with a controller output of 4.0 mA.
Upon ascertaining the as-found readings, evaluate the results against the required specification. If required, perform zero and span adjustments until
no further adjustment is required. Then, repeat all
test points to record as-left readings. Many organizations do not require periodic calibration of I/P
transducers, positioners, or control valves. The justification is the control signal will adjust the output
until the required setpoint is achieved based
on the process measurement. This is true, but you want to make
sure the output loop is performing correctly.


The best way to do so is to check the calibration periodically.
Calibration of the valve positioner can be performed at
the same time as the I/P in a loop calibration. Simply tee in the pressure module at the I/P outlet in the I/P calibration. Record
the valve position at each test point. If calibrating the valve positioner separately, connect an input test pressure
regulator or hand pump, and monitor the input pressure applied with a pressure standard.
If there is no supply air, connect the required supply air to the positioner.
Apply the pressure for the desired test points and record valve position.


0-100% valve position. In this case, apply 3.0, 6.0, 9.0,
12.0, and 15.0 psig. The expected valve positions
should be 0, 25, 50, 75, and 100%, respectively. The valve position indicator on the stem usually
marks off in 5% or 10% increments. Therefore, a best estimate of the
valve position may be all you can obtain.
In other cases, a valve position detector provides a remote indication to a DCS.
In such cases, ensure both indicators are working properly.
Many organizations do not require calibration of valve positioners for these reasons.
There's much documentation that control valve positioner performance is responsible for significant loss in system efficiency and, therefore,
increased costs. As to control valve calibration, the
process is similar to positioner calibration in that one applies a pressure signal to
the actuator and then tallies the resulting valve position. This step can take place with the positioner calibration, if applicable, and it can happen in conjunction with
I/P calibration. Remember to ensure the system is in a safe condition if performing the calibration in the field.
In addition, know the correct action, direct or reverse, and
fail position before starting. Nicholas Sheble (nsheble@isa.org) edits the Certification department for InTech
magazine. This article is from Michael Cable's book Calibration: A Technician's
Guide, ISA Press 2005. Cable is a Level 3 Certified Control System Technician and is the validation manager at Argos Therapeutics.



The addition of feedback to a control system results in several
important advantages. A process, whatever its nature, is subject to a changing
environment, aging, ignorance of the exact values of the process parameters, and other natural factors which affect
a control process. In the open-loop system, all these errors and changes result
in a changing and inaccurate output. However, a closed-loop system senses
the change in the output due to the process changes and attempts to correct the
output. The sensitivity of a control system to parameter variations is of prime importance.
A primary advantage of a closed-loop feedback control system
is its ability to reduce the system's sensitivity.



One of the most important characteristics of control systems
is their transient response, which often must be adjusted until
it is satisfactory. If an open-loop control system
does not provide a satisfactory response, then the process must be
replaced or modified. By contrast, a closed-loop system can often be adjusted to yield the desired response by adjusting the feedback
loop parameters. A second important effect of feedback in a control system is the control and partial elimination of the effect
of disturbance signals. Many control systems are subject to extraneous
disturbance signals which cause the system to provide an inaccurate
output. Feedback systems have the beneficial aspect that the effect of distortion, noise, and unwanted disturbances can be effectively reduced.



We have four common temperature sensors used in industrial instrumentation.
RTD responds to heat by increasing its resistance to electric current.
This is similar to RTD, except that its resistance decreases as it is heated.
Note that, in both the RTD and Thermistor temperature sensors, the current
variation due to temperature change is usually very small.
Current through an RTD or Thermistor must be compared to current through another circuit containing identical devices at a reference temperature
to detect the change. The freezing temperature of water is used as the
reference temperature. This type of temperature sensors respond to temperature increases by increasing reverse-bias current across P-N junctions, generating
a small but detectable current or voltage
proportional to temperature.
The integrated circuit may contain its own amplifier.




Control valves plays significant role for increasing profitability, efficiency and safety of process industries.
The providers of control valves are persistently upgrading and evolving their technology and research and development events in order to meet the
ever-changing demands of the manufacturers of several different industries.
Introduction of several stringent regulations regarding environmental pollution are being
executed in the development of control valves. Due to introduction of several stringent environment laws the
global control valves market is expected to be impacted in a negative manner at a significant pace in the near future such as the sales and design of control valves.

Moreover, these factors are expected to further hamper the growth of global control
valves market. Globally industry players of global control valves market are leveraging market growth through development of several
innovative control valves and its components that includes smart actuators and control valve positioners.
The development of innovative components along with research and development activities will enable the key players of the industry to design exclusive expansion strategies
and new opportunities for growth.


OCV Waterworks control valves offer a wide variety of waterworks valve
designs, engineered to meet the entire spectrum of water utility system requirements.
By controlling pressure, rate of flow, surge and pump control, engineers and specifiers rely on our valves
to help improve the efficiency of both supply and distribution. OCV also has altitude control valves to service elevated water tanks and digital control valves to interface with high-level
SCADA systems. Altitude and Check Valves Play Integral Part
in Air Force Base Fire Protection Reliable water levels
are a necessity when it comes to water towers - especially when water towers are relied upon for fire
protection.


Five water towers are situated on the Tinker Air Force base complex just outside of Oklahoma City.
As Houston and surrounding areas continue to be
developed, building guidelines and safety requirements have grown as
well. Throughout Harris County, all buildings that require
a fire or domestic water pump necessitate the installation of a break
tank. In this application, the OCV Model 108-4 Pressure Sustaining
and Solenoid Valve is feeding the pond at a golf
course from the residential water system. It controls
the back pressure in the line and also the level of the pond.
This application is for a municipal entity that provides water to a district about
one mile downstream.


The customer remotely opens the 16" Model 22X Electronic Position Control Valve to a certain percentage to allow a certain amount of water to flow to the district downstream. This is a standard municipality pump room with OCV Pump Control valve working in conjunction with OCV Two-Way Altitude Valves to allow the municipality to pump water from a river into a water storage tank on top of a hill. In this application, the Model 22VMU ValveMeter Ultra in installed in a back flushing filter system that is only used when the customer needs to backflush one of the two filter medias. Flow during the back flushing process is critical; if flow is too high, it blows the media, which is expensive to replace. In this application, the 22VMU ValveMeter Ultra is installed inside of a pumping station that is pulling water from a reservoir to supply into an industrial park. OCV, part of The MAT Holding Group, is a company that is a global leader in the control valve industry. OCV valves can be found in some capacity in nearly every country throughout the world.


Ethernet or Internet based valve control systems are convenient since they allow you to access your control system at any time. They are easy to set up since Ethernet cabling is now usually pre-installed in most buildings. You may need to open or close a valve based on a schedule or conditions. You can set up the valve control system to open or close based on logic or you can access the system remotely and manually open or close a valve. There are different ways you can implement such a system. Ethernet and Modbus TCP based valve control devices like ET-7017 can take a 4-20mA measurement from a float sensor in a tank and output 40 VDC to control a valve.


ET-7017 can bring the level of the tank into the valve control system through data acquisition over the Modbus TCP driver. 20mA input types. ET-7017 also has 4 digital output channels that can output 5 to 50 VDC to control a valve. With PC based free EZ Data Logger software, the valve control system can be set up such that the valve can open or close based on the level of the tank. 1 which means if analog input channel number 2 is greater than 15mA then turn digital output channel number 2 on. You can set up email alarms to get sent out when the tank is above a desired range. You can also set up buttons that you can click which can manually turn the valves on or off. You can set up bar graphs that can show you the level in a tank.


With EZ Data Logger you can also set up trend graphs. You can also set up the system to log the data so you can track the level in the tank and the status of the valves for analysis. A more advanced valve control system can be set up with KingView SCADA software. KingView is PC based SCADA (Supervisory Control and Data Acquisition) software that can be used to set up a control and monitoring system. With KingView, you can add graphical animation, publish the system to the web for access over the internet, display data acquisition information with more advanced trend graphs, data logging, comparison curves, x-y charts, and implement system redundancy. It comes with an hour of free web based training.


The itemized report of Global Control Valves Market assessed by gifted specialists is divided into Application and Product. The investigators at QY Research Groups give customers the most recent data about the unpredictable points of interest of the market concerning driving districts, players, items and applications. QY Research Groups is a company that simplifies how analysts and decision makers get industry data for their business. Our unique colossal technology has been developed to offer refined search capabilities designed to exploit the long tail of free market research whilst eliminating irrelevant results. QY Research Groups is the collection of market intelligence products and services on the Web. We offer reports and update our collection daily to provide you with instant online access to the world's most complete and current database of expert insights on Global industries, companies, products, and trends.


A well designed and installed lighting control system can add convenience and security to the home. A control system controls all the lights in the home via a central brain or processor. Lighting keypads replace light switches and talk back to the processor - any keypad can control any lighting channel. A lighting channel being any lamp, or group of lights, which the home owner requires control over. In practice a lighting keypad would be installed in locations where a light switch would traditionally be installed. As any keypad can control any lighting channel then the keypad by the front door can switch all the communal areas on or the keypad in the master bedroom can switch all off.


Switching lights on and off is only one part of a lighting system. Imagine a living room with a couple of table lamps, a couple of wall lights and two ceiling pendants. A lighting system can dim any of the lamps to preset levels - allowing instant recall of scenes via keypads. A living room usually has more than one function - TV watching, reading and entertaining to name a few. Recalling scenes ensures comfort whilst performing different activities whilst showing the home off at it's best. Entertaining scenes can be particularly important and complex. Advanced lighting control systems also have easy to use security modes - automatically replaying the last two weeks activity when the home alarm is set.


Simulating owner occupation can be the most effective way to put would be thieves off. Automatically bringing lights on when the owner is not home also allows the owner to return home to a lit home - showing the home off at its best whilst increasing personal security when approaching the home. The other great benefit of a residential lighting system is energy saving - dimming a lamp by 50% can save corresponding amounts of energy. The more advanced lighting control systems can even spot a light which has been left on and gently dim it to off - ensuring the en-suite light isn't left on all night by mistake.


Automation is the use of several control systems for operating equipment such as boilers and heat treating ovens, machinery, switching in telephone networks, stabilization and steering of aircraft, ships and other applications with reduced or minimal human intervention. Automation saves labor and energy and improves quality and precision. Automation can be broadly divided into process and discrete automation. Instrumentation is the science and art of control and measurement of process variables within a manufacturing or production area. Several types of instrumentation techniques include network instrumentation, programmable instrumentation, operating systems instrumentation and processor instrumentation. Instrumentation goes together with automation as instruments are used in the automation process to measure, analyze or monitor the level of a product’s performance. One of the major factors driving the growth of automation instrumentation market is the increasing demand of automation instrument from process industries.


[img]https://slideplayer.com/slide/12247757/72/images/1/SCADA TRAINING Field Instruments & Sensors AJAY K BASU.jpg[/img]However, lack of effective product differentiation may pose a challenge to the growth of automation instrumentation market. For example, various automation instrument retailers face augmented competition from regional and local vendors owing to lack of effective product differentiation. To overcome this problem, many retailers have started presenting customized automation solutions which not only meet the client needs but is offered to them at a competitive price. As a result, several companies across process industries which include Chemical, Oil and Gas and Petrochemical are opting for automation instruments so that they could enhance their operational efficiency. By geography, countries such as Brazil, Russia, India and China are witnessing rapid growth in the automation instrumentation market due to the upstream industries of Refining Chemicals along with Electric Utilities, Oil & Gas, Metals and Mining. Some of the key players in the market include Emerson Electric Co., BB Ltd., Yokogawa Electric Corp.


Instrumentation Tools Android App is the unique place for Instrumentation engineers worldwide who want to learn and study. We provide a variety of technical articles presented on very understandable way, as well as FREE handy guides, Instrumentation online tools and MS Excel spreadsheets that will make your life much easier. Every day the app was updated with new articles, tools & technical information. So please visiting the app. If you want any information/working principles/tools/support/queries related to instrumentation then please post your queries in our comment section, which available under the bottom of each article. About Instrumentation Android App : I am Proud to say that this is the First Android App designed especially for Our Instrumentation Professionals which is available in Google Play Store. Support Our Instrumentation App: Like it, Share it, Give Comments & Encourage us.

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