Fieldbus H1

mumkin pernah denger industrial bus, macamnya ada banyak : HART, AS-i, Modbus, Profibus, Fieldbus. Nah yg ter mutahir adalah Fieldbus menggunakan H1 link. Ane coba sharing untuk yg fieldbus....

What is Fieldbus?

1. A fieldbus is an all-digital, serial two-way, multi-drop communication System.
2. H1 link (31.25kbps) interconnects field equipment (Sensors, Actuators & I/O).
3. HSE (High Speed Ethernet, 100mbps) provides integration of high speedcontrollers, subsystems

    (via Linking Device) and data servers and workstation.

Integrated Architecture

1. Management Information Systems (MIS), Enterprise Resource Planning (ERP), and Human Machine  

    Interface (HMI) access the H1 Fieldbus information via the Data Servers.

H1 Benefits

More Data for Better Decision Making

1. Fieldbus allows “multiple variables” from each device to be brought into the control system for archiving,  

    trend analysis, process optimization, reporting, predictive maintenance and for asset management.
2. Fieldbus distortion-free characteristics digital communication enables improved control capability which

    can improve product yields.

Expanded View of Process & Instrument

1. Self Diagnostics and communication capabilities of microprocessor based fieldbus devices helps reduce

    downtime and improve plant safety.
2. Plant operation and Maintenance personnel can be notified and corrective actions taken quickly and

    safely.

Reduction in System Hardware

1. Standard Function Blocks is used to implement the Control Strategy.
2. Many control system functions such as AI, PID and AO can be performed by the field device through the

    use of these Standard Function Blocks.
3. Distribution of control into field devices can reduced the amount of hardware and cabinet footprint

    needed.

Sample Implementation

• 192 segments per cabinet
– Assuming using 8-segment redundant H1card
• Certified for installation in Class 1 Division 2 / Zone 2 hazardous locations
• Translates to 3,072 FF devices per System Cabinet
– It could be more when each FF device may provide up to 16 process values ( ie.Temperature

   Multiplexers)

3,072 FF devices per System Cabinet

Wiring Savings

1. The H1 fieldbus allows many devices to be connected to a single wire pair.
2. This results in less wire, fewer intrinsic safety barriers and fewer marshaling cabinets.

Summary

• Control in-the-field
– Reduced loading on DCS Controllers
• Reduced number of intrinsic safety barriers
– Only H1 card in the Marshalling
• Reduced number of Input/Output Converters
• Reduced number of Power Supplies and Cabinets.
• Reduced size of equipment Rooms.
• Remote configuration of devices.
• Increased accuracy of measurements
• Easier evolution due to standardized function blocks
• Increased sophistication and flexibility of instrumentation
• Increased uptime due to less equipment,
• better self diagnostics and remote diagnostics
• More information available for Operations.

4-20mA versus Fieldbus

1. A H1 fieldbus retains and optimizes the desired features of the 4-20mA analog system:
    - single Loop integrity.
    - a standardized physical interface to the wire.
    - a bus-powered devices on a single wire pair.
    - intrinsic safety options.

2. In addition, FOUNDATION Fieldbus enables:
    - 25 x faster communication speed compared to HART
    - increased capabilities (due to full digital communication).
    - reduced wiring and terminations (multiple device on one wire).
    - increased selection of suppliers (due to interoperability)
    - reduced control room loading (control on wire)
    - connection to HSE backbon

Rukun Haji

Ciselang 12 maret 2011
lanjutan kajian kitab fathul qorib....

Rukun Haji ada 4 yaitu :

1. Ihrom dengan niat menjalankan ibadah haji.

Niat/cita2 haji harus ada di hati sejak akil baligh, agar ketika wafat dan belum sempat haji maka niat itu akan menggenapkan rukun Islam yg 5.

2. Wukuf di padang Arofah

Haji adalah ibadah dengan rukun qolbi dan fi'li.
Arti wukuf sendiri adalah diam/netep. waktunya tanggal 9 Zulhijah dari pagi hari.

3. Thowaf 7x mengelilingi Ka'bah.

hitungannya mulai dari Hajar Aswad, memutarnya berlawanan dengan jarum jam.

4. Sa'i,

lari-lari kecil dari shofa ke marwah. Mulai dari bukit Shofa dan Finish di bukit Marwah.

setelah selesai semua rukun haji maka menyukur rambut (menurut pendapat yg masyhur).

-----------

Ciselang, 19 Maret 2011

Rukun haji Ihrom dengan Niat wajib di dahulukan.
Mendahulukan thowah sebelum Sa'i
Thowaf kudum adalah thowaf penghormatan ketika sampai di Mekkah, hukumnya sunnah.


Rukun Umroh

1. Ihrom dan Niat
2. Thowaf
3. Sa'i
4. cukur rambut.


Kewajiban2 dalam haji yg bukan rukun :

1. Ihrom dari miqot.

a. Miqot zamani musim Haji yaitu Syawal, Dzulqoidah dan 10 hari bulan zulhijah
    Miqot zamani untuk umroh adalah 1 tahun penuh.

b. Miqot Makani (tempat mulai Ihrom)
    -- Untuk Penduduk Mekkah, begitu keluar rumah langsung Ihrom dan Niat
    -- Untuk dari Madinah tempatnya di Dzul hulaifah
    -- Untuk dari Syam, Mesir Maroko tempatnya di Juhfah
    -- Untuk dari Yaman di Yalamlam
    -- Untuk dari Hijaz dan Yaman di Qornul Manazil
    -- Untuk dari Timur di Dzatu Irqin

2. Melempar Jumroh
    a. Kubro (ula) --->7 lontaran batu kerikil
    b. Wustho --->7 lontaran batu kerikil
    c. Aqoba --->7 lontaran batu kerikil

bila sekali lempar 7 batu tetep di hitung 1 lontaran. dan yg di lontarkan harus batu.

3. Mnyukur rambut
minimal 3 helai rambut (untuk laki2 sunnahnya di gundul)

Perhitungan Kapasitor Bank

secara umum mungkin yg di kenal dunia industri (khususnya elektrikal) penggunaan capasitor bank adalah untuk perbaikan faktor daya (power factor improvement). Mengapa perlu di perbaiki? faktor daya (cos phi) yg rendah mengkibatkan pembebanan pada trafo menjadi lebih besar. Mengapa faktor daya menjadi rendah ? biasanya beban di dunia industri adalah beban induktif (motor2 listrik) yg menyebabkan faktor daya menjadi rendah. Nah penggunaan kapasitor bank ini untuk memberikan baban capasitif yg akan mengeliminir beban induktif tersebut. mungkin masih ingat dengan segi tiga daya. Untuk teorinya/perhitungaanya munkin bisa liat di

http://dunia-listrik.blogspot.com/2008/12/perbaikan-faktor-daya-menggunakan.html

nah untuk gampangnya kita mendesign kapasitor bank, dunlud  spreadsheet di bawah ini

Capacitor Bank

Konsep dasar untuk proteksi di area explosive atmospheres (ATEX Directive 94/9/EC atau ATEX 100a)

Apakah  ATEX?

“ATEX”  adalah “ATmosphere EXplosive”, i.e., explosive atmosphere.

Yang kita bahas sekarang adalah ATEX DIRECTIVE 94/9/EC untuk  EQUIPMENT (peralatan)
sebenarnya ada satu lagi yaitu : ATEX DIRECTIVE 99/92/EC untu  WORKPLACE (area kerja), yang akan kita bahas lain waktu.

Biasanya pada alat Instrumentasi atau elektrik yang di pakai di Hazardous area ada keterangan  seperti ini :
II 2 G Ex de IIC T6

apakah maksudnya ??

II 2 G : EQUIPMENT GROUP II Category 2 Zone 1 (Gas Atmosphere)
Ex : Conformity with harmonized European standards
de : “d” flameproof enclosure & "e" increased safety
IIC : GAS GROUPS IIC (typical Gas Hydrogen)

T6 : Temperature class = maximum temperature that the electrical equipment can reach
         (T6=85 degC)


Untuk lebih jelsnya dapat lihat gambar di bawah.

sumber gambar : http://www.stahl.de/







How to read P&IDs / Bagaimana cara membaca P&IDs (Piping and Instrumentation Diagrams

di tulis oleh Dave Harrold, senior editor dari Control Engineering

Instrumentation detail varies with the degree of design complexity. For example, simplified or conceptual designs, often called process flow diagrams, provide less detail than fully developed piping and instrumentation diagrams (P&IDs). Being able to understand instrumentation symbols appearing on diagrams means understanding ANSI/ISA’s S5.1-1984 (R 1992) Instrumentation symbols and identification standard. S5.1 that defines how each symbol is constructed using graphical elements, alpha and numeric identification codes, abbreviations, function blocks, and connecting lines.

Deciphering symbols

 

ISA S5.1 defines four graphical elements—discrete instruments, shared control/display, computer function, and programmable logic controller—and groups them into three location categories (primary location, auxiliary location, and field mounted).

Discrete instruments are indicated by circular elements. Shared control/display elements are circles surrounded by a square. Computer functions are indicted by a hexagon and programmable logic controller (PLC) functions are shown as a triangle inside a square.

Adding a single horizontal bar across any of the four graphical elements indicates the function resides in the primary location category. A double line indicates an auxiliary location, and no line places the device or function in the field. Devices located behind a panel-board in some other inaccessible location are shown with a dashed horizontal line

Letter and number combinations appear inside each graphical element and letter combinations are defined by the ISA standard. Numbers are user assigned and schemes vary with some companies use of sequential numbering, others tie the instrument number to the process line number, and still others adopt unique and sometimes unusual numbering systems.

The first letter defines the measured or initiating variables such as Analysis (A), Flow (F), Temperature (T), etc. with succeeding letters defining readout, passive, or output functions such as Indicator (I), Record (R), Transmit (T), and so forth.

Example shows the story

Referring to the Example P&ID diagram, FT 101 represents a field-mounted flow transmitter connected via electrical signals (dotted line) to flow indicating controller FIC 101 located in a shared control/display device. A square root extraction of the input signal is applied as part of FIC 101’s functionality. The output of FIC 101 is an electrical signal to TY 101 located in an inaccessible or behind-the-panel-board location. The output signal from TY 101 is a pneumatic signal (line with double forward slash marks) making TY 101 an I/P (current to pneumatic transducer). TT 101 and TIC 101 are similar to FT 101 and FIC 101 but are measuring, indicating, and controlling temperature. TIC 101’s output is connected via an internal software or data link (line with bubbles) to the setpoint (SP) of FIC 101 to form a cascade control strategy.

Often P&ID’s include a cover page where common and typical terms, symbols, numbering systems, etc., are defined. On the example, Typical YIC would likely appear on the cover page and the simplified form of YIC would appear throughout the P&IDs.

Typical YIC indicates an on/off valve is controlled by a solenoid valve and is fitted with limit switches to indicate open (ZSH) and closed (ZSL) positions. All inputs and outputs are wired to a PLC that’s accessible to the operator (diamond in a square with a solid horizontal line). The letter 'Y' indicates an event, state, or presence. The letter 'I' depicts indication is provided, and the letter 'C' means control takes place in this device.

Adherence to ISA’s S5.1 Instrumentation Symbols and Identification standard ensures a consistent, system independent means of communicating instrumentation, control, and automation intent is developed for everyone to understand.

 

RS232 to TTY converter

buat yg suka ngulik Siemens Simatic S5 tapi ga punya PG 

Basic of Gas Metering System

di tulis oleh Anwar Sutan, (copas dari milis migas-indonesia http://www.migas-indonesia.com/ )

There are a few types of gas meter. All of these meters at the end have one goal, which is to get a reliable result of measurement that can be converted to amount of money. In the old days, measurement is only based on standard volume total. But the amount of energy will be different for different composition of gas. That’s why nowadays people use energy measurement as a standard for buying and selling gas. There are a few types of gas meter, we have mass meters, and we have volume meters. We classify the type of meter base on what the raw output of the meter is. Then from the raw data, with the help of some calculation standards, we will have parameters such as density, compressibility, calorific value, etc. These parameters will help us determine all other totalisers.

Gross Volume Flow Rate

For a volumetric meter, there are two methods of getting gross volume flow rate. The first one is where the signal from the meter is in the form of frequency. And the second one is where the signal from the meter is in the form of velocity of gas. If the signal from the meter is in the form of frequency, then the meter has to have a k factor.

K factor is a value that determines how many pulses represents 1 volume-unit. For instance the k factor is 1000 pulses/m3. It means that 1 m3 will be represented by 1000 pulses. If the signal taken from the meter is vog which taken from serial connection, then to get the flow rate, the velocity has to be multiplied by the area of the internal diameter of the pipe. No meter is linear. That’s why they need to have wet calibration, which a meter being calibrated is compared to a more accurate meter on a few flow rate points. A value that corrects the deviation between the meter being calibrated and the reference meter is called by meter factor.

A meter factor value is applied in the meter being calibrated. On some meters such as usm, when wet calibration is done, meter factor is applied in the usm it self. In that case, there is no need to apply the meter factor in the flow computer for the gross volume flow rate calculation anymore. But it is a choice of a customer to disable the meter factor in the meter and apply it in flow computer. The only thing to be noticed is that meter factor must not be applied in both flow computer and meter. Another thing that will affect flow rate is that pipe expands with increase of temperature and pressure. Because of the expansion, volume of the gas that goes through will be different depending on the temperature and pressure. To compensate this, there is correction factor on the temperature (ctsm) and correction factor on the pressure (cpsm).

The value 3600 is for volume/hour. It will be 86400 for volume/day. It varies depends on the flow rate unit.

Standard Volume Flow Rate
Standard volume flow rate is a flow rate that is calculated at standard pressure and standard temperature. These standard pressure and temperature are standards defined by standard association such as AGA, ISO, etc or standard pressure and temperature agreed by buyer and seller.

At most applications, these parameters such as compressibility and density are calculated. The calculation is defined in standards. AGA 8 is on of the most used standard to get the compressibility and density. Density also defined in ISO 6976 standard.

Mass Flow rate
Mass flow rate is defined by how much mass goes through a meter in every certain time unit. Mass can be determined by knowing fluid density. The formula for mass volume is:

For mass meter such as orifice, mass flow rate is the raw output from the calculation of the orifice parameters. And by knowing the line and standard density, standard volume and gross volume will be determined.

Energy Flow rate

Energy flow rate is defined by how much energy goes through a meter in every certain time unit. Energy can be determined by knowing Gross heating value which is defined by how much energy contain in certain standard volume unit. The formula for energy flow rate is:

Calculation for GHV is defined in standards such as ISO 6976 and GPA 2172.

Macam-macam type pengendali/controller

PENGENDALI ON-OFF / PENGENDALI DUA POSISI (ON-OFF CONTROLLER)

·        Hanya bekerja pada dua posisi, yaitu posisi “on” dan posisi “off”

·        Misal final control element berupa control valve hanya terbuka penuh atau tertutup penuh

·        Control valve tidak akan pernah bekerja di daerah antara 0 sampai 100 %

·        Hasil pengendalian on-off akan menyebabkan PV yang bergelombang

·        Memiliki dead band

·        Contoh : pengendalian suhu pada setrika listrik atau pada pompa air listrik otomatis

PENGENDALI  PROPOSIONAL (P Controller)

·        Fungsi transfer  :               o = Gc . i

·        o = MV dan i = error = SV - PV

·        Gain :         Gc = 100% / PB

·        PB = Propotional Band

·        Setting PB berkisar antara 0 % hingga 500 %

·        Perubahan input diikuti secara langsung oleh perubahan output

·        Karena fungsi ini tidak bergantung oleh waktu, maka dynamic gain pengendali ini sama dengan steady state gain-nya

·        Sistem pengendali ini selalu menghasilkan offset (error steady state)

·        Untuk menghilangkan offset, maka pengendali proposional harus ditambah dengan BIAS

o = Gc.i + B

·        Bias disebut juga dengan manual reset

·        Tidak semua controller mempunyai fasilitas ini

·        PB yang kecil menghasilkan koreksi yang besar

·        PB yang besar menghasilkan koreksi yang kecil

PENGENDALI  INTEGRAL (I Controller)

·        Fungsi Transfer :   o = 1/Ti * Gc * ò i dt  + B

·        Ti = integral time [ minute / repeat ]

·        Ti = waktu yang dibutuhkan oleh pengendali integral untuk mencapai output sebesar input

·        Misal Ti = 2 menit/repeat artinya pengendali memerlukan waktu 2  menit untuk mencapai output sama dengan input

·        Ti yang kecil menyebabkan reaksi pengendali cepat

·        Ti yang besar menyebabkan reaksi pengendali lambat

·        Kelemahan :

- tidak disertai kemampuan bereaksi dengan cepat

- muncul dynamic gain dan phase shift pada unit controller

- muncul reset wind up

RESET WIND UP

·        Output Integral akan naik terus selama unit pengendali integral ‘melihat’ adanya error

·        Ini dapat terjadi karena :

-         Ti terlampau kecil

-         Control Valve yang marginal (kekecilan)

-         Proses mengalami Shut down

-         Proses merupakan proses batch, yang menghendaki operasinya di startup dan shutdown berulang kali

·        Reset wind up  dapat di atas dengan anti reset wind up  yang mendisfungsikan pengendali integral untuk sementara

PENGENDALI  P-I (PI Controller)

·        Untuk mengatasi offset pada proposional, maka digunakan pengendali integral

·        Untuk mempercepat respon integral digunakan pengendali proposional

·        Kedua pengendali dipasang parallel

·        Karena sifatnya yang sederhana dan efektif, pengendali ini paling banyak dipakai, sekitar 75 % dipakai pengendali ini

·        Hubungan input output pengendali PI dalam fungsi waktu

·        Untuk penyetelan harga P dan I :

-         integral time dibuat maksimum dulu, Ti = ∞

-         sambil mengamati respon yang terjadi, baru Ti diperkecil untuk mengurangi offset yang terjadi

PENGENDALI  DIFERENSIAL (D Controller)

·        Respon PI masih lama untuk proses temperatur

·        Karena proses temperatur memerlukan energi ekstra di saat-saat awal ketika terjadi perubahan load atau perubahan set point

·        Pengendali ini tidak dapat dipakai sendiri, harus dengan pengendali lain seperti : PD atau PID

·        Fungsi Transfer :   o = Gc * Td de/dt + B

·        Td = derivative time

·        Besarnya output bergantung pada kecepatan input (rate) dan Td-nya

·        Td yang besar menghasilkan koreksi yang besar

·        Td yang kecil menhasilkan koreksi yang kecil

What's the "RS" in RS232/RS485/RS422?

Let's start out by talking about this nasty "RS" business. So, what the heck does the "RS" stand for? You had better sit down for this one. It means Recommended Standard

That's right! The RS stands for Recommended Standard. Nothing really agreed upon or official. At least not in the sense of the "made-by-committee" standards like IEEE-1284 and IEEE-1394.

What does this mean? Because RS standards are merely recommended and technically general, lots of manufacturers develop products that are at best crappy. They cut corners and cheat in order to manufacture cheaper products.

We have tried not to make crappy products. That is why you don't see any port powered products put out by Integrity Instruments. Engineers have enough headaches the way it is!

---

Simplex & Duplex
One of the most fundamental concepts of communications technology is the difference between Simplex and Duplex.

Simplex can be viewed as a communications "one-way street". Data only flows in one direction. That is to say, a device can be a receiver or a transmitter exclusively. A simplex device is not a transceiver. A good example of simplex communications is an FM radio station and your car radio. Information flows only in one direction where the radio station is the transmitter and the receiver is your car radio. Simplex is not often used in computer communications because there is no way to verify when or if data is received. However, simplex communications is a very efficient way to distributed vast amounts of information to a large number of receivers. 

Duplex communications overcome the limits of Simplex communications by allowing the devices to act as transceivers. Duplex communication data flow in both directions thereby allowing verification and control of data reception/transmission. Exactly when data flows bi-directionally further defines Duplex communications.

Full Duplex devices can transmit and receive data at the same time. RS232 is a fine example of Full Duplex communications. There are separate transmit and receive signal lines that allow data to flow in both directions simultaneously. RS422 devices also operate Full Duplex.

Half Duplex devices have the dubious honor of allowing both transmission and receiving, but not at the same time. Essentially only one device can transmit at a time while all other half duplex devices receive. Devices operate as transceivers, but not simultaneous transmit and receive. RS485 operates in a half duplex manner.

Here is the short version of the critical specifications. Unfortunately, these are subject to interpretation by individual manufacturers. That is why RS232 is often regarded as an incredibly un-standard communications protocol.

One important note. You will see that one of the major differences between RS232 and RS422/RS485 is the signalling mode. RS232 is unbalanced while RS422/RS485 is balanced. An unbalanced signal is represented by a single signal wire where a voltage level on that one wire is used to transmit/receive binary 1 and 0: the can be considered a push signal driver. On the other hand, a balanced signal is represented by a pair of wires where a voltage difference is used to transmit/receive binary information: sort of a push-pull signal driver. In short, unbalanced voltage level signal travels slower and shorter than a balanced voltage difference signal.

PID Controller Tuning

·        Tujuan sistem pengendalian : menjaga atau mengendalikan supaya nilai PV selalu sama dengan nilai SV

·        Upaya yang dilakukan adalah dengan menyetel sistem pengendalian agar PV mengikuti SV dengan respon overdamped atau underdamped (sistem disetel agar respon tidak berosilasi), keadaan inilah yang disebut stabil

·        Tuning : penyetelan nilai PB, Ti, dan Td, yang menyebabkan respon dari ouput proses (PV) akan stabil

·        Semua elemen dari proses pengendali mempunyai dead time dan time constant

·        Dengan perubahan load dan kondisi operasi maka kedua nilai diatas akan ikut berubah, sehingga mempengaruhi respon dari proses

·        Metoda tuning parameter :

1.       Metoda Ziegler & Nichols

·        Metoda Osilasi

·        Metoda Kurva reaksi

2.       Metoda Cohen Coon

·        Metoda Quarter Decay

METODA OSILASI

·        Metoda ini hanya menggunakan pengendali P (propotional band) dan gain, sehingga respon proses tepat berosilasi dengan amplitude tetap (sustain oscillation)

·        Beberapa istilah yang dipakai :

·        Gcu     = ultimate gain

·        PBu     = ultimate PB

·        Pu       = ultimate period

Pengendali	P	PI	PID
PB	PBu / 0,5	PBu / 0,45	PBu / 0,6
Ti	-	Pu  / 1,2	Pu / 2
Td	-	-	Pu / 8

·        Metoda ini berbahaya untuk dilakukan dilapangan, karena menghasilkan respon proses yang berosilasi

·        Jika respon proses menjadi undamped (osilasi dengan amplituda yang membesar), maka controller harus dipindahkan ke posisi manual

·        Langkah-langkah :

1.      Manual-kan controller

2.      Ubah P = 100%, I = ∞, D = 0

3.      Buat SV=MV= 50 % atau di daerah kerja yang diharapkan

4.      Auto-kan controller

5.      Beri gangguan pada proses (dengan merubah SV sesaat)

6.      Setelah beberapa saat turunkan kembali SV ke harga semula

7.      Perhatikan respon proses

8.      Jika responnya underdamped, perkecil PB agar gain membesar

9.      Jika responnya undamped, secepat mungkin pindahkan ke mode manual. Lalu perbesar PB agar gain mengecil

10. Ulangi langkah  3, 4, dan 5 hingga didapatkan osilasi dengan amplituda tetap

 

METODA KURVA REAKSI

·        Metoda ini paling sering digunakan karena sifatnya praktis dan tidak membahayakan proses

Pengendali	P	PI	PID
PB	Rl * L	Rl / 0,9	R1 * L / 2
Ti	-	3,33 L	2L
Td	-	-	0,5L

·        Rl = unit reaction rate = R / bukaan valve

·        L = dead time

·        Langkah-langkah :

-         manualkan controller

-         aktifkan recorder

-         ubah MV sebesar 5% hingga 10%

-         didapatkan kurva seperti berikut :

-         gambarlah garis singgung (slope), lalu hitung harga reaction rate (R) dimana R = B/A

-         Hitung Rl = R/bukaan valve

-         Hitung dead time-nya (L)

-         Masukkan harga L dan Rl ke dalam tabel diatas

METODA QUARTER DECAY

·        Metoda ini memperbaiki metoda osilasi

·        Respon proses dibuat quarter-amplitude decay, yang periodanya akan digunakan untuk menyetel Ti dan Td

Pengendali	PI	PID
Ti	PB	1,5 * PB
Td		PB / 6

·        Langkah-langkah :

-         manualkan controller

-         ubah SV=MV=50%

-         ubah PB= 100%

-         autokan controller

-         naikkan SV sesaat dengan perubahan sebesar 5%-10%, setelah beberapa saat kembalikan ke nilai semula

-         usahakan menyetel PB hingga didapat respon dengan quarter decay

-         catat perioda respon

-         masukkan harga PB ke dalam tabel diatas