INSTRUMENTATION FOR PREVENTING EXPLOSION AND FIRE (SAFETY)

Naturally, we must safely accomplish measurement, control calculations, and process modulation through adjusting the final element.  Control systems contribute to safe process operation through basic control design, valve failure positions, alarms, safety interlock systems, and pressure relief systems (e.g., Marlin, 2000; AIChE, 1993; Lees, 1996).  This section addresses one important hazardous condition, fire and explosion, that is affected by the design and implementation of control and transmission equipment.  The material in this section is applicable to a wide range of processes and industries using either analog or digital transmission.

SIGNAL TRANSMISSION OF CONTROL SYSTEM

Most process control systems involve a structure of distributed equipment, with sensors and valves at the process equipment and the control calculations and displays located in a remote, centralized facility.  Therefore, values of key variables must be communicated between the sensors, calculations and valves (or other final elements).  Schematics of typical control systems with analog and digital control are given in Figure 4.0.1.

Analyzers

The term analyzer refers to any sensor that measures a physical property of the process material.  This property could relate to purity (e.g., mole % of various components), a basic physical property (e.g., density or viscosity), or an indication of product quality demanded by the customers in the final use of the material (e.g., gasoline octane or fuel heating value).  

Level Measurement Equipment

Level of liquid in a vessel should be maintained above the exit pipe because if the vessel empties the exit flow will become zero, a situation that would upset downstream processes and could damage pumping equipment that requires liquid.  Also, the level should not overflow an open vessel nor should it exit through a vapor line of a closed vessel, which could disturb a process designed for vapor.  In addition, level can influence the performance of a process; the most common example is a liquid phase chemical reactor.  Level is usually reported as percent of span, rather than in length (e.g., m).

Pressure Measurement Equipment

Most liquid and all gaseous materials in the process industries are contained within closed vessels.  For the safety of plant personnel and protection of the vessel, pressure in the vessel is controlled.   In addition, pressured is controlled because it influences key process operations like vapor-liquid equilibrium, chemical reaction rate, and fluid flow. 

The following pressure sensors are based on mechanical principles, i.e., deformation based on force.

Flow Measurement Equipment

Flow measurement is critical to determine the amount of material purchased and sold, and in these applications, very accurate flow measurement is required.  In addition, flows throughout the process should the regulated near their desired values with small variability; in these applications, good reproducibility is usually sufficient.  Flowing systems require energy, typically provided by pumps and compressors, to produce a pressure difference as the driving force, and flow sensors should introduce a small flow resistance, increasing the process energy consumption as little as possible. 

Temperature Measurement Equipment

Temperature control is important for separation and reaction processes, and temperature must be maintained within limits to ensure safe and reliable operation of process equipment.   Temperature can be measured by many methods; several of the more common are described in this subsection.  You should understand the strengths and limitations of each sensor, so that you can select the best sensor for each application.

Sensors and Tranducers

Sensors are used for process monitoring and for process control.  These are essential elements of safe and profitable plant operation that can be achieved only if the proper sensors are selected and installed in the correct locations.  While sensors differ greatly in their physical principles, their selection can be guided by the analysis of a small set of issues, which are presented in this section.  Each issue is introduced here with process examples, and details on the issues are provided in the remainder of this site for the most common sensors in the process industries.

Introduction Instrumentation and Process Control

Sensors to measure process conditions and valves to influence process operations are essential for all aspects of engineering practice.  Engineers want to design and operate processes that remain in safe conditions, produce the desired amounts of high quality products and are profitable.  Therefore, engineers must provide measuring devices for key variables and valves (or other devices, such as variable speed electric motors) to influence of “steer” the process.  This site provides educational material on sensors and valves for use in the process industries. 

PROCESS CONTROL ELEMENTS IN THE LOOP

A simple process control loop consists of three elements, the measurement, the controller and the final control element.

Measurement

Measurements have got to be one of the most important equipment in any processing plant.  Any decision made on what the plant should do is based on what the measurements tell us.  In the context of process control, all controller decisions are similarly based on measurements. 

Elements Process Control for the Loop System

A simple process control loop consists of three elements, the measurement, the controller and the final control element.

Measurement

Measurements have got to be one of the most important equipment in any processing plant.  Any decision made on what the plant should do is based on what the measurements tell us.  In the context of process control, all controller decisions are similarly based on measurements. 

Control and Instrumentasi (C&I)

Control and Instrumentation (C & I) is a new branch of engineering that became popular after the rapid computer hard ware and shoftware. Since then the world discovered microprocessor industry is also quick to apply it to automasisasi production facilities.
If baehula first time the department is only known in the industry Mechanic, Electric, Civil, Chemical (for chemical process) and now the Department of C & I meerupakan department that must exist for modern industry. Because the equipment industry now uses either Automatic control Micro Controller, PLC, DCS, SCADA or maybe even for several industrial processes are already using AI (artificial intellegency) Artificial Intelligence. And untu automatic equipment was needed from the plant to the sensor measurements are transmitted to a control device or control device otherwise ordered something to be translated into an action field that both pistons, actuators, motors, servo or the other.
Of course, to manage and maintain the tools above are not able to carelessly people, they must be educated and have sufficient scientific background to master the equipment.
OK unfortunately we are the country's users, so for the development of our country has not shown a real sense for the industry practices in the field, because the Control and Instrumentation products in addition must show that the control device functioning properly should also be reliable and accurate in operation. Thus the designer engineer will think fifty times or more to wear an artificial sensor or control local / untested hand made his reputation. And unfortunately also the homeland of Industrial largely still in design from abroad.
Apart from design to design all of our people would still get parts for installation yes, konstruction and maintenance, which currently is required by the industries in Indonesia. Start the beverage industry, food, fertilizer until any chemical or Oil & Gas.
Unfortunately workers who qualified for this sector is extremely rare, so the field is very difficult to get a ready workforce and has a good competitive, much less than fresh graduate is extremely rare, there are only a few schools that mengkususkan to print the ready to use in this field.
In my experience the practice field about 12 years although this knowledge to hand konstruction, and maintenance is not so difficult to learn but because of the lack of information and human resources at least educatif side, I always get the workers are not ready to wear. Once we give a hand on training is also training2 basic control and instrumentation (usually in Lippi's easy and cheap) they are in time 6bln - one year before it can adjust to his job. And so is fair if many large perusahaan2 many educated-trained tenaga2 hijack this because of the scarcity of their numbers in the field.
Even now there are some majors Instrumentation PTN is open but the ability is still less than most of the graduates according to the needs in the field, although his basic taught on campus because of the lag or no difference of perception between teachers with the skills industry needs graduates to be less ready to use, even though their There is one school which I think has prepared graduates ready to use STMP bandung majors such instrumentation, but now becomes a difficult thing, because for most technicians use the minimum requirement ijazzah D3, so that although the skill of the STMP bandung administratively capable but still not satisfied. For now recruiting workers among industries in addition to the Control and Instrumentation Instrumentation also take power from the Electrical and Engineering Physics.
What work has something to do view the Control and Instrumentation (C & I)? As in other fields then in the field of C & I also have several pieces that can work on, or they can be involved and pursue a career in it.
1. Engineering and Construction
In our country it is mashed handled our guys are very low but now engineering2 joint operation with abroad has been common, so even though it was from an American company, or from Germany but they employ many workers in the country, especially if projectnya in Indonsia. Because we've been able to tenaga2 addition they will also perform better luck view salary expenditures in the sector, of course degan the same quality but much lower spending then they will elect people to partner Indonesian engineering and construction. Power engineers even now we have started reaching the Asean and the Middle East. What was done by a qualified C & I Engineer in the engineering sector performed well and what power the C & I Engineer in the construction sector?
Workers in engineering usually evaluate the process and translate into a language program that usually digigital using DCS or PLC. Many kinds of DCS / PLC for diindustri (Yokogawa, alleb Bradley, Siemen, Honeywell, Mitsubishi, Balley etc) but in principle the same, and now masing2 product user should try to make it easier both in terms of its physical design, and software. Then after so benuk logic flow process to meet the needs of course there is how much input is needed and how much output is needed, and certainly in the process of translating the language into computer language must be based on a strong philosophy about the instrumentation, control and safety. From the input and output of this sensor is shown what needs to be there, and what the actuator must be provided. Danentunya for communication between automation devices, automation devices with various kinds of equipment needed in the field or the same network cable data network. So is that their engineering duties and mnghitung it all.
It's complicated but now everyone can do a lot of people a good view of the data base so that it is not a hard thing. Until finally the output from this is the image 2 Enginneering controller topology design, data sheets, Instrumentation, P & IDs, Logic Diagrams, Wiring diagram, hook ups, .. etc alarm schedule to detail its installation must also be ready. And then this part of the project engineer to calculate the price / cost for purchase until the next installation of the device is also cost his installation. And finally the execution ground.
Execution of the Project still requires the I & C engineer reliable as well as he should know how it fitted him also the need ideology how the system works, of course, an understanding of the logic diagrams and computer networks are absolutely necessary, as well as knowledge of the field instruments are required because the I & C Engineer will be responsible the function of the C & I at the new plant was built to control the process can work well or not.
The event certainly thrilling when prosses komissioning and startup Project because the results of all efforts to project engineer disigner enginneer specified here. if the calculation is correct if wrong lancarlah projet then crushed a lead project for financial loss is not small. Here, the role seoeang I & C engineer in the Engineering and Construction.
2. I & C Maintenance and Engineering Solution Engineering.
Now the factory has been finished, Commissioning of the project team have returned and who operate factories in the service team and how if kontrollernya not working or reading off a sensor, or the system was unstable kjontrolnya / reliable. Here, I & C maintenance tasks. He had to ideology bagaimanan control system works ranging from field until soft warenya. Because of this control system is a plant and field brain senses and instruments are working executor of the brain commands the I & C is a vital function for the organization of the plant.
And dalamperkembangannya whose names technologies continue to develop and age of the plant got older then the re-design and updating of equipment is very mutalak required, these usually called up grading it to this one I & C engineers can do yourself if the job is not too much but sometimes resources executive at the plant not sufficient, it is often this in subkan engineering solutions to other companies. Engineering solution for this company is much also I & C engineers to gait, they are in charge of upgrading from the factory with a design and materials, sometimes decades ago replaced with modern materials technology and new tar depends on the purpose of the plant.
Kirakira this is where an I & C engineers can take part in the existing plant.
3. Reseach and development
For large companies such control system Siemens, Allen Bredley, ABB, Yokogawa etc his affection in this country read Indonesia bukanlha place, they entered his reseach dinegaranya respectively. Due to the development of instrumentation and control are closely linked with research and materials technology shoftware also require high investment in technology and the venom was done in his base states respectively. So disampin I also do not have experience about this case I have not seen in Indonesia there are commercial companies that do this. In many research universities in terms of both material (technology / materials) are also soft ware engineering, but unfortunately they lack many of the popular to work with a large automation company, atua their design is less known in the industrial world bahakan in our own domestic industry . ?? i do not know.
4. Agent and Distributor
It is clearly seen its trivial but it turns out an agent and distributor is vital, because without them the plant needs can not be fulfilled, without them the new tools we can not buy. Task I & C engineer typically provides the technical guidelines are also warranty when they sell equipment installed.
5. Other
aja said that this search itself ...
Kogan Creek, QLD. Aust. 21 june 2008

First Aid if Virus Infected

Monday, June 22, 2009 | 11:18 pm
What to do if a virus infected computer? Do not rush out Pasopati science, aka "format" and "reinstall Windows"! In some cases the virus, such as Conficker, this does not solve the problem. Your computer will become infected again once connected to the network,
So what? Try to always handle yourself with a two-step that PCplus show. You lose the same period a virus?
Use System Restore This is the stance of the easiest but powerful if you want the computer to run both the pre-infected with the virus. System Restore is one of the leading features in Windows XP and Vista which by default is enabled when the OS was first installed.

With System Restore you can create a restore point (which also automatically made periodically by Windows). It's like a time machine. That is, when the system is 'acting' is not fair, because a virus or any programs or drivers installed, we can restore the configuration of Windows, such as when a computer healthy.

For example, there is a new application-OS install and cause problems / frequent crashes. Instead of a headache and spend time analyzing fault location program, just call Restore point when the program has not yet been installed. And Voila, all registry settings and other Windows configuration again as usual.

Restore Point can be applied if you know roughly when the virus infects a computer, or in case you do not run a virus file. There's only condition, ie, System Restore is not disabled, by a user or a virus (some viruses such as Conficker disable System Restore when the computer attack the victim).

Unfortunately, System Restore often backfire. Jka already entered the Restore point, the virus that infects a computer it is protected by System Restore. As a result, even though it was cleaned several times with the antivirus, the virus occasionally stuck firmly in the files restore point. The virus will 'rise' again from the restore point. This is very annoying.

Therefore, each time step is cleaning the virus, the first step is to disable System Restore. This is so that the virus was not protected by System Restore. Here are the steps to restore its original state (Restore Point): 1. Click [Start] [All Programs] [Accessoris] [System Tools] [System Restore].
2. Three choices will appear in the System Restore wizard screen, namely: a. Restore my computer to an Earlier time. Use this to restore the system at any given time. b. Create a restore point. Use to create a restore point at this time. c. Undo my restoration. Use to cancel the restore points are made. Here PCplus select [Restore my computer to an Earlier time] [Next].
3. Next, you will be faced with a calendar. Choose a time when the computer is still stable or not infected with a virus, then click [Next].
4. The next wizard appears on the confirmation screen. Select [Next].

5. System restore will work, then restart the computer. You need to wait a bit longer, about 15 minutes (depending on your hardware), in order to restore Windows Restore Point.
Unfortunately, in some cases, the virus tries to turn off System Restore, so this feature is not useful. So use the System Restore feature only if the virus has not been turned off this feature.
Manual Cleaning If System Restore fails to restore the computer system, there are still other ways. This last stance is "Cleaning Manual."
Most importantly, DO NOT PANIC! The next step, data Save your work immediately and close all other programs running. Make sure the data has been stored at the correct location or right and you know their location.
After that, do the backup data to another storage media (USB flash disks, CDs, etc.), which is separate from the computer's hard disk. This is to prevent unwanted things on your data. If possible, it helps remove the infected hard disk and copy your important data onto the hard disk / other media.
After all the above you do, run the following steps:
1. Install an antivirus program and do antivirus UPDATE. If your computer has antivirus software installed, just do antivirus updates in order to prevent possible infection of new viruses. If necessary, a free tool unduhlah in Norman Malware Cleaner
http://download.norman.no/public/Norman_Malware_Cleaner.exe
2. Immediate DISCONNECT Internet connection and local network connection (LAN) settings to prevent virus infection to the local network or reinfection from the network / Internet. To disconnect a network or Internet connection, this step: a. Click [Start] [Control Panel] [Network and Internet Connections] [Network Connection]. b. In Network Connection, select the Internet connection / network that exists, then right click and click [Disable].

3. Disable "System Restore" to facilitate the cleaning of a virus that is protected by a Restore Point and prevent the virus re-infect the computer. How:
a. Right click on My Computer, click [Properties]. b. Then in the [System Properties] [System Restore]. c. On the tab [System Restore], check the option [Turn off System Restore on all drives]. d. Click [Apply] [OK].

4. Do SCAN virus. Allow a full antivirus scan on your computer, including USB flash disks (if any). After the scan is complete, restart the computer if necessary. Alternatively, do the scanning by using the Removal tool.

5. CLEAN temporary files from the possibility of entry of the virus. Here's how: a. Click [Start] [All Programs] [Accessoris] [System Tools] [Disk Cleanup]. b. In [Disk Cleanup], select the drive that will be cleaned (by default is C:). c. Let [Disk Cleanup] scanning first. d. Select the temporary files that will be cleaned, then [OK]. e. Let the cleanup process to work through to completion.
***
If you have done the above two moments, but your computer still having problems, please do not hesitate, in consultation with the IT or your antivirus vendor.
Source: PCplus