note about motor control starter.
Wednesday, December 2, 2009
Pneumatic system
Today, i want talk about pneumatic system. This system always in industrial explicitly instrumentation equipments in petrochemical plant, where it use for preventative danger like fire and explosion. Furthermore in industrial now, the manufacturer want increase their profit so they need to improve they production produce and reduce their man-power. For that reason, they change their system to the automation system. When use automation system in their production, the system will integrated with pneumatic system, PLC, and any equipments. So it show how important pneumatic system in our industrial world. So i attach the note about pneumatic system for your reference.
Hari ini, saya mahu bercakap tentang sistem pneumatik. Sistem ini selalu digunakan dalam industri terutamanya peralatan instrumentasi di loji petrokimia, dimana ia digunakan untuk mengatasi bahaya seperti kebakaran dan letupan. Tambahan pula dalam industri sekarang, pekilang mahu tingkatkan keuntungan maka mereka hendaklah perbaiki sistem pengeluaran produk dan kurangkan bilangan pekerjanya. Atas alasan itu, pekilang menukarkan sistem mereka yang sedia ada kepada sistem automasi. Apabila sistem automasi digunakan dalam pengeluaran, sistem tersebut akan berintergasi dengan sistem pneumatik , PLC dan peralatan lain lagi. Ini menunjukkan kepentingan sistem pneumatik dalam dunia industri. Maka saya lampirkan nota tentang sistem pneumatik untuk rujukan kamu.
Saturday, November 28, 2009
Selamat Datang TaufiknurHidayah Blog
Assalamualaikum,
Blog ini saya gunakan sebagai medan pengantara untuk pengkongsian ilmu, idea, dan pengalaman khususnya dalam bidang automasi dan sistem elektronik terutamanya mikropengawal. Saya berusaha menjadikan ia untuk memudahkan pengguna mendapatkan komponen elektrikal dan elektronik terutamanya di Sarawak. Ia juga digunakan sebagai bahan rujukan dan tutorial kepada pelajar saya di Jabatan Kejuruteraan Petrokimia, PKS.
This blog I use as middle field for sharing knowledges, idea, and experiences especially in automation and electronic system for micro controller. i effort to make it for make user easy to find electrical and electronic components explicitly in Sarawak. It also use for reference materials and tutorial for my student at Petrochemical Engineering Department, PKS.
What Is A Control Valve?
Process plants consist of hundreds, or even thousands, of control loops all networked together to produce a product to be offered for sale. Each of these control loops is designed to keep some important process variable such as pressure, flow, level, temperature, etc. within a required operating range to ensure the quality of the end product. Each of these loops receives and internally creates disturbances that detrimentally affect the process variable, and interaction from other loops in the network provides disturbances that influence the process
variable.
To reduce the effect of these load disturbances, sensors and transmitters collect information about the process variable and its relationship to some desired set point. A controller then
processes this information and decides what must be done to get the process variable back to where it should be after a load disturbance occurs. When all the measuring, comparing, and calculating are done, some type of final control element must implement the strategy selected
by the controller.
The most common final control element in the process control industries is the control valve. The control valve manipulates a flowing fluid, such as gas, steam, water, or chemical compounds, to compensate for the load disturbance and keep the regulated process variable as close as possible to the desired set point.
Many people who talk about control valves or valves are really referring to a control valve assembly. The control valve assembly typically consists of the valve body, the internal trim parts, an actuator to provide the motive power to operate the valve, and a variety of additional valve accessories, which can include positioners, transducers, supply pressure regulators, manual operators, snubbers, or limit switches.
Other chapters of this handbook supply more detail about each of these control valve assembly components. Whether it is called a valve, control valve or a control valve assembly, is not as important as recognizing that the control valve is a critical part of the control loop. It is not accurate to say that the control valve is the most important part of the loop. It is useful to think of a control loop as an instrumentation chain. Like any other chain, the whole chain is only as good as its weakest link. It is important to ensure that the control valve is not the weakest link.
Following are definitions for process control, sliding-stem control valve, rotary-shaft control valve, and other control valve functions and characteristics terminology.
Electronic Scoring Game (Fun Game)
You can play this game alone or with your friends. The circuit comprises a timer IC, two decade counters and a display driver along with a 7-segment display. The game is simple. As stated above, it is a scoring game and the competitor who scores 100 points rapidly (in short steps) is the winner. For scoring, one has the option of pressing either switch S2 or S3. Switch S2, when pressed, makes the counter count in the forward direction, while switch S3 helps to count downwards.
Before starting a fresh game, and for that matter even a fresh move, you must press switch S1 to reset the circuit. Thereafter, press any of the two switches, i.e. S2 or S3. On pressing switch S2 or S3, the counters BCD outputs change very rapidly and when you release the switch, the last number remains latched at the output of IC2. The latched BCD number is input to BCD to 7-segment decoder/driver IC3 which drives a common-anode display DIS1. However, you can read this number only when you press switch S4. The sequence of operations for playing the game between, say two players X and Y, is summarized below:
1. Player X starts by momentary pressing of reset switch S1 followed by pressing and releasing of either switch S2 or S3. Thereafter he presses switch S4 to read the display (score) and notes down this number (say X1) manually.
2. Player Y also starts by momentary pressing of switch S1 followed by pressing of switch S2 or S3 and then notes down his score (say Y1), after pressing switch S4, exactly in the same fashion as done by the first player.
3. Player X again presses switch S1 and repeats the steps shown in step 1 above and notes down his new score (say, X2). He adds up this score to his previous score. The same procedure is repeated by player Y in his turn.
4. The game carries on until the score attained by one of the two players totals up to or exceeds 100, to be declared as the winner.
Several players can participate in this game, with each getting a chance to score during his own turn. The assembly can be done using a multipurpose board. Fix the display (LEDs and 7-segment display) on top of the cabinet along with the three switches. The supply voltage for the circuit is 5V
1. Player X starts by momentary pressing of reset switch S1 followed by pressing and releasing of either switch S2 or S3. Thereafter he presses switch S4 to read the display (score) and notes down this number (say X1) manually.
2. Player Y also starts by momentary pressing of switch S1 followed by pressing of switch S2 or S3 and then notes down his score (say Y1), after pressing switch S4, exactly in the same fashion as done by the first player.
3. Player X again presses switch S1 and repeats the steps shown in step 1 above and notes down his new score (say, X2). He adds up this score to his previous score. The same procedure is repeated by player Y in his turn.
4. The game carries on until the score attained by one of the two players totals up to or exceeds 100, to be declared as the winner.
Several players can participate in this game, with each getting a chance to score during his own turn. The assembly can be done using a multipurpose board. Fix the display (LEDs and 7-segment display) on top of the cabinet along with the three switches. The supply voltage for the circuit is 5V
simple Stepper Motor DiY
The circuit shown above can be used to control a unipolar stepper motor which has FOUR coils (I've swiped it off an old fax machine). The above circuit can be for a motor current of up to about 500mA per winding with suitable heat sinks for the SL100. For higher currents power transistors like 2N3055 can be used as darlington pair along with SL100. The diodes are used to protect the transistor from transients.
Activating sequence:-
Inputs |
Coils Energised | |
D0 | D1 | |
0 | 0 | A,B |
0 | 1 | B,C |
1 | 0 | C,D |
1 | 1 | D,A |
To reverse the motor just reverse the above sequence viz. 11,10,01,00.
Alternately a 2bit UP/DOWN counter can also be used to control the direction , and a 555 multi-vibrator can be used to control the speed
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