OLEH: HENDRIANTO HUSADA

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PENDAHULUANARSITEKTUR & KOMPONEN-KOMPONEN PLCINPUT/OUTPUT PLCDASAR-DASAR PEMROGRAMAN PLCKOMPONEN-KOMPONEN PEMROGRAMAN PLCBAHASA PEMROGRAMAN PLCLADDER DIAGRAMREALISASI RANGKAIAN LOGIKA KE LADDER DIAGRAMINSTRUKSI PLC ,TIMER,COUNTER & INSTRUKSI LAINNYAAPLIKASI PLC

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UTS30%UAS40%TUGAS20%ABSEN10%------------------------ 100%**

SETIAWAN, IWAN:PROGRAMMABLE LOGIC CONTROLLER DAN TEKNIK PERANCANGAN SISTEM KONTROL , PENERBIT ANDI OFFSET 2006PETRUZELLA : PROGRAMMABLE LOGIC CONTROLLERWEBB , JOHN W & REIS , RONALD A: PROGRAMMABLE LOGIC CONTROLLERS:Principles and Applications, fourth Edition, Prentice Hall 1999DUNNING, GARY:INTRODUCTION TO PROGRAMMABLE LOGIC CONTROLLERS ,Delmar Publisher ,1998**

DEFINISI PLCSEJARAH PLCKEUNTUNGAN & KERUGIAN PILCJENIS-JENIS PLCMEREK PLC**

SUATU PIRANTI ELEKTRONIK DIGITAL YANG MENGGUNAKAN MEMORI INTERNAL YANG DAPAT DIPROGRAM UNTUK MEDIA PENYIMPANAN INTERNAL DARI INSTRUKSI-INSTRUKSI DALAM IMPLEMENTASI FUNGSI-FUNGSI KHUSUS SEPERI LOGIKA, SEQUENCING , TIMING, COUNTING DAN ARITMETIKA UNTUK MENGONTROL MELALUI MODUL-MODUL ANALOG ATAU DIGITAL , BERBAGAI TIPE MESIN-MESIN ATAU PROSES.

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SUATU KOMPUTER UNTUK INDUSTRI/ KHUSUS YANG DIGUNAKAN UNTUK PENGONTROLAN SISTEM INDUSTRI SUATU KOMPUTER UNTUK INDUSTRI DIMANA PIRANTI KONTROL SEPERTI LIMIT SWITCHES, PUSH BUTTON, SENSOR PROXIMITY ATAU PHOTO ELECTRIC,FLOAT SWITCHES ATAU PRESSURE SWITCH MEMBERIKAN SINYAL KONTROL MASUK KE UNIT**

MENDAPATKAN PENGONTROLAN SECARA KOMPLIT SUATU PROSES MANUFAKTURMENCAPAI KONSISTENSI DALAM MANUFAKTURMEMPERBAIKI KUALITAS DAN AKURASIBEKERJA PADA LINGKUNGAN YANG SUSAHMENAIKKAN PRODUKTIVITASMEMPERSINGKAT WAKTU MEMASARKANKONTROL INVENTORYBERUBAH SECARA CEPAT**

PENGENALAN PLCPROGRAMABLE LOGIC CONTROLLER

Sebuah alat yang digunakan untuk menggantikan rangkaian sederetan relai yang dijumpai pada sistem kontrol proses konvensional

Programmable Logic Controller (PLC) merupakan perangkat special-purpose dengan keandalan tinggi. PLC berupa komputer mikro yang digunakan untuk memenuhi tugas pengendalian secara logika, berdasarkan program yang telah ditentukan.

Bekerja dengan cara mengamati masukan/sensor dn melakukan proses sesuai dengan yang dibutuhkan ( sesuai dengan program yang diatur )

SEJARAH PLCDiperkenalkan pada tahun 1960-an yang bertujuan untuk menghilangkan beban ongkos perawatan berbasis relaiPLC pertama didunia MODICON ( modular digital controller ) 084Pertengahan tahun 1970-an PLC berbasis prosesor AMD 29011980-an memperkecil ukuran PLC dan pembuatan perangkat lunak melalui program simbolik dengan PC dan penggunaan handled programer.Tahun 1990-an telah dilakukan reduksi protokol baru dan modernisasi lapisan fisik dan peningkatan standar serta penggabungan bahasa pemrograman dibawah SI

*SEJARAH PLC1968 Programmable concept developed1969 Hardware CPU controller, with logic instructions, 1 K of memory and 128 I/O points 1974 Use of several (multi) processors within a PLC - timers and counters; arithmetic operations; 12 K of memory and 1024 I/O points1976 Remote input/output systems introduced1977 Microprocessors - based PLC introduced

*SEJARAH PLC

1980 Intelligent I/O modules developedEnhanced communications facilitiesEnhanced software features (e.g. documentation)Use of personal microcomputers asprogramming aids1983 Low - cost small PLCs introduced1985 on Networking of all levels of PLC, computer and machine using SCADA software.

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PLC VS KONVESIONALPLC BERFUNGSI MEMPERCEPAT PROSES YANG SELAMA INI MASIH ONVENSIONAL MENJADI OTOMATIS

PENGGUNAAN PLC BERTUJUAN UNTUK MEMPERMUDAH PROSES-PROSES YANG SANGAT KOMPLEKS DAN SULIT YANG HARUS DITANGANI DENGAN CEPAT, PLC JUGA SEKALIGUS DAPAT MENGGANTIKAN BEBERAPA ALAT YANG DIPERLUKAN.

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Karakteristik PLC:

Karakteristik PLC:

Ukuran kecil Pemograman yang ampuh Duplikasian mudah dan murah Diagnosis terintegrasi & central Domunetasi text dan grafik Harga murah Aplikasi universal

Sedikit perkabelan ( wiring) Wiring antara piranti(devices) dan relay contacts dilakukan pada program Mudah dan cepat untuk melakukan pengubahan . Petunjuk troubleshooting membuat pemrograman lebih mudah dan mengurangi downtime. komponen-komponennya reliabel bisa berfungsi selama beberapa tahun sebelum rusak .

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FLEKSIBILITAS: SATU PLC BISA MENGONTROL BANYAK MESIN

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Shorter project implementation time.

Easier modification

Project cost can be accurately calculated.

Shorter training time required.

Design easily changed using software ( changes and addition to specifications can be processed by software.

A wide range of control application

Easy maintenance.

High Reliability

Standardization of Controller hardware.

Able to withstand Harsh plant/process environments (Operate normally under severe conditions of temperature, humidity, voltage fluctuations and noises).

CONTROL TYPE:FUNCTIONSSequence ControlConventional Relay Control Logic replacerTimers/ CounterPCB Card controller replacerAuto/Semi-auto/Manual control of machine and process.

Advanced/ Sophisticated ControlArithmetic operation (+, -, , )Information HandlingAnalog Control (Temperature, Pressure )P.I.D (Proportional Integral Derivation)Servo Motor ControlStepper Motor control

CONTROL TYPE:FUNCTIONSSupervisory ControlProcess monitoring and alarm.Fault Diagnostic and monitoringInterfacing with Computer (RS-232C/RS 422)Printer/ ASCII InterfacingFactory Automation NetworkingLocal Area Network (LAN)Wide Area Network (WAN)Factory Automation (F.A), Flexible Manufacturing System (F.M.S) & Computer Integrated Manufacturing (C.I.M).

Kriteria Pemilihan PLC1. HardwareJumlah input dan outputTegangan operasi input dan outputProteksi terhadap short circuitIndikasi status input dan outputJumlah counter/timerJumllah flagJenis dan ukuran memoriMaipulasi bit/wordWaktu sikulus bite/1 kb statement

Pemrosesan alarmInterfaceUkuran dimensiKondisi sekitarUnit: compact/modular

Kriteria Pemilihan PLC2. SoftwareKapasitas programerKenyamanan programerBahasa pemogramanTest dan comissioningKualitas dokummentasi program

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*Areas of Application Manufacturing / Machining

Food / Beverage

Metals

Power

Mining

Petrochemical / Chemical

AplikasiPLC banyak digunakan pada aplikasi-aplikasi industri misalnya : pada proses pengepakan, penanganan bahan, perakitan otomatis dan lain sebagainya.

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*MEREK-MEREK PLCAMERICAN1. Allen Bradley2. Gould Modicon3. Texas Instruments 4. General Electric5. Westinghouse6. Cutter Hammer7. Square D

EUROPEAN1. Siemens2. Klockner & Mouller3. Festo 4. Telemechanique

*MEREK-MEREK PLCJAPANESE1. Toshiba2. Omron3. Fanuc4. Mitsubishi

KOREA1. LG2. SAMSUNG

*PLC Size1. SMALL- it covers units with up to 128 I/Os and memories up to 2 Kbytes. - these PLCs are capable of providing simple to advance levels or machine controls.2. MEDIUM- have up to 2048 I/Os and memories up to 32 Kbytes.3. LARGE- the most sophisticated units of the PLC family. They have up to 8192 I/Os and memories up to 750 Kbytes.- can control individual production processes or entire plant.

Compact PLCModular PLCPLC Plug-in Card

Manufacturer: OMRON, Allen Bradley, Mitsubishi, NAIS, Siemens, Toshiba, Festo etc.Jenis kontruksi PLC:

i. Compact PLC:

Compact PLC MELSEC FX3U Figure 1: Compact PLC

Modular PLCFigure 2: Modular PLC

iii. PLC Plug-in CardFigure 3: Plug-in Card PLC

Aplikasi PLC sangat luas dari industri otomotif, makanan, pengemasan dan lain sebagainya.

HARDWARE: ARSITEKUR PLC & BAGIAN-BAGIAN PLCSOFTWARE:LADDER DIAGRAM**

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ARSITEKTUR PLC**

PROCESSOR

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3.1 Processor Architecture for PLC:Figure 4: Design of Basic Microcomputer

*Major Components of a Common PLCPOWER SUPPLY

Provides the voltage needed to run the primary PLC components

I/O MODULES

Provides signal conversion and isolation between the internal logic- level signals inside the PLC and the fields high level signal.

*Major Components of a Common PLCPROCESSOR

Provides intelligence to command and govern the activities of the entire PLC systems. MEMORYUsed to store data and program

PROGRAMMING DEVICE

used to enter the desired program that will determine the sequence of operation and control of process equipment or driven machine.

*ProcessorThe processor module contains the PLCs microprocessor, its supporting circuitry, and its memory system.

The main function of the microprocessor is to analyze data coming from field sensors through input modules, make decisions based on the users defined control program and return signal back through output modules to the field devices. Field sensors: switches, flow, level, pressure, temp. transmitters, etc. Field output devices: motors, valves, solenoids, lamps, or audible devices.

The memory system in the processor module has two parts: a system memory and an application memory.

*Programming DeviceAlso known as:

Industrial Terminal ( Allen Bradley )

Program Development Terminal ( General Electric )

Programming Panel ( Gould Modicon )

Programmer ( Square D )

Program Loader ( Idec-Izumi )

Programming Console ( Keyence / Omron )

*Programming DeviceTypes:

Hand held unit with LED / LCD display

Desktop type with a CRT display

Compatible computer terminal

*I/O Module The I/O interface section of a PLC connects it to external field devices.

The main purpose of the I/O interface is to condition the various signals received from or sent to the external input and output devices.

Input modules converts signals from discrete or analog input devices to logic levels acceptable to PLCs processor.

Output modules converts signal from the processor to levels capable of driving the connected discrete or analog output devices.

Central Processing Unit (CPU)

The CPU controls, monitors and supervises all operations within PLC.

It is also caries out programmed instructions stored in the memory.

An internal communications highway also known as a bus system, carries information to and from the CPU, memory and I/O units under the control of the CPU.

Unit Pengolah Pusat (CPU - Central Processing Unit) Unit pengolah pusat atau CPU merupakan otak dari sebuah kontroler PLC. CPU itu sendiri biasanya merupakan sebuah mikrokontroler (versi mini mikrokontroler lengkap)CPU ini juga menangani komunikasi dengan piranti eksternal,interkonektivitas antar bagian-bagian internal PLC, eksekusi program, manajemen memori, mengawasi atau mengamati masukan dan memberikan sinyal ke keluaran(sesuai dengan proses atau program yang dijalankan).

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Memory UnitFor storage of programs.

The users ladder logic program, the state of I/O in the memory of PLC.

The main program and the other programs necessary for the operation of PLC.

The organization of the data and information in the memory is called memory map.

MemoriMemori sistem (saat ini banyak yang mengimplementasikan penggunaan teknologi flash) digunakan oleh PLC untuk sistem kontrol proses. Selain berfungsi untuk menyimpan "sistem operasi", juga digunakan untuk menyimpan program yang harus dijalankan, dalam bentuk biner, hasil terjemahan diagram tangga yang dibuat oleh pengguna atau pemrogram.Memori pengguna dibagi menjadi beberapa blok yang memiliki fungsi khusus.Beberapa bagian memori digunakan untuk menyimpan status masukan dan keluaran.

3.1.1 FUNCTION OF EACH BLOCK:

RAM Random Access MemoryROMRead Only Memory (read)This memory can be read from and written to.This memory can be read onlyStoring all users programsStoring all systems programEntire contents will be lost if power is switched off.Memory content remain when the power is switched off.

Catu daya PLCCatu daya listrik digunakan untuk memberikan pasokan catu daya ke seluruh bagian PLC (termasuk CPU, memori dan lain-lain). Kebanyakan PLC bekerja pada catu daya 24 VDC atau 220 VAC. Beberapa PLC catu dayanya terpisah (sebagai modul tersendiri)

Input Unit:Function as a medium that connects the external input devices (Switch, sensor & timer)

Output Unit:Function as a medium that connects the external output devices to the CPU within PLC.( Lamp, motor & solenoid )3.1.1 FUNCTION OF EACH BLOCK:

Kecerdasan sebuah sistem terotomasi sangat tergantung pada kemampuan sebuah PLC untuk membaca sinyal dari berbagai macam jenis sensor dan pirantipiranti masukan lainnya. sinyal-sinyal masukan tersebut dapat berupa logik (ON atau OFF) maupun analog. PLC kecil biasanya hanya memiliki jalur masukan digital saja, sedangkan yang besar mampu menerima masukan analog melalui unit khusus yang terpadu dengan PLC-nya. Salah satu sinyal analog yang sering dijumpai adalah sinyal arus 4 hingga 20mA (atau mV) yang diperoleh dari berbagai macam sensor.

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Referring to PLC standard display Internal Relay:

Consoles LCD Display if user use Mnemonic Code Programming.

Monitor Screenif user use software programming method.

LCD DisplayMonitor Screen

sistem otomatis tidaklah lengkap jika tidak ada fasilitas keluaran atau fasilitas untuk menghubungkan dengan alat-alat eksternal (yang dikendalikan). Beberapa alat atau piranti yang banyak digunakan adalah motor, selenoida, relai, lampu indikator, speaker dan lain sebagainya. Keluaran ini dapat berupa analog maupun digital. Keluaran digital bertingkah seperti sebuah saklar, menghubungkan dan memutuskan jalur. Keluaran analog digunakan untuk menghasilkan sinyal analog (misalnya, perubahan tegangan untuk pengendalian motor secara regulasi linear sehingga diperoleh kecepatan putar tertentu).

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Programming UnitConsist of 2 devices:i.Programming Console

ii.Computer

g. Secondary Storage UnitThis unit related to CPU where all program and information were kept.

h.Power Supply Unit:

Supplies DC power to the Central Processing Unit, Input Unit and Output Unit.

Printing UnitUsed to print control system programming that controlled by PLC wether graphically or text.

Setiap PLC biasanya memiliki jumlah masukan dan keluaran yang terbatas. Jika diinginkan, jumlah ini dapat ditambahkan menggunakan sebuah modul keluaran dan masukan tambahan (I/O expansion atau I/O extension module).

*Memory Map OrganizationSystem memory includes an area called the EXECUTIVE, composed of permanently-stored programs that direct all system activities, such as execution of the users control program, communication with peripheral devices, and other system activities.The system memory also contains the routines that implement the PLCs instruction set, which is composed of specific control functions such as logic, sequencing, timing, counting, and arithmetic.System memory is generally built from read-only memory devices. The application memory is divided into the data table area and user program area.The data table stores any data associated with the users control program, such as system input and output status data, and any stored constants, variables, or preset values. The data table is where data is monitored, manipulated, and changed for control purposes. The user program area is where the programmed instructions entered by the user are stored as an application control program. Data TableUser Program

*Memory DesignsVOLATILE. A volatile memory is one that loses its stored information when power is removed.

Even momentary losses of power will erase any information stored or programmed on a volatile memory chip.

Common Type of Volatile Memory

RAM. Random Access Memory(Read/Write) Read/write indicates that the information stored in the memory can be retrieved or read, while write indicates that the user can program or write information into the memory.

*Memory Designs

The words random access refer to the ability of any location (address) in the memory to be accessed or used. Ram memory is used for both the user memory (ladder diagrams) and storage memory in many PLCs.

RAM memory must have battery backup to retain or protect the stored program.

*Memory DesignsSeveral Types of RAM Memory:

1.MOS 2.HMOS 3.CMOS

The CMOS-RAM (Complimentary Metal Oxide Semiconductor) is probably one of the most popular. CMOS-RAM is popular because it has a very low current drain when not being accessed (15microamps.), and the information stored in memory can be retained by as little as 2Vdc.

*Memory DesignsNON-VOLATILEHas the ability to retain stored information when power is removed, accidentally or intentionally. These memories do not require battery back-up.

Common Type of Non-Volatile Memory

ROM, Read Only MemoryRead only indicates that the information stored in memory can be read only and cannot be changed. Information in ROM is placed there by the manufacturer for the internal use and operation of the PLC.

*Memory DesignsOther Types of Non-Volatile Memory

PROM, Programmable Read Only MemoryAllows initial and/or additional information to be written into the chip.

PROM may be written into only once after being received from the PLC manufacturer; programming is accomplish by pulses of current.

The current melts the fusible links in the device, preventing it from being reprogrammed. This type of memory is used to prevent unauthorized program changes.

*Memory DesignsEPROM, Erasable Programmable Read Only Memory

Ideally suited when program storage is to be semi-permanent or additional security is needed to prevent unauthorized program changes.

The EPROM chip has a quartz window over a silicon material that contains the electronic integrated circuits. This window normally is covered by an opaque material, but when the opaque material is removed and the circuitry exposed to ultra violet light, the memory content can be erased.

The EPROM chip is also referred to as UVPROM.

*Memory DesignsEEPROM, Electrically Erasable Programmable Read Only Memory

Also referred to as E2PROM, is a chip that can be programmed using a standard programming device and can be erased by the proper signal being applied to the erase pin.

EEPROM is used primarily as a non-volatile backup for the normal RAM memory. If the program in RAM is lost or erased, a copy of the program stored on an EEPROM chip can be down loaded into the RAM.

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*PLC OperationBasic Function of a Typical PLC

Read all field input devices via the input interfaces, execute the user program stored in application memory, then, based on whatever control scheme has been programmed by the user, turn the field output devices on or off, or perform whatever control is necessary for the process application.

This process of sequentially reading the inputs, executing the program in memory, and updating the outputs is known as scanning.

Examples of PLC Programming Software:

1. Allen-Bradley Rockwell Software RSLogix5002. Modicon - Modsoft3. Omron - Syswin4. GE-Fanuc Series 6 LogicMaster65. Square D- PowerLogic6. Texas Instruments Simatic6. Telemecanique Modicon TSX Micro

*PLC CommunicationsCommon Uses of PLC Communications Ports

Changing resident PLC programs - uploading/downloading from a supervisory controller (Laptop or desktop computer). Forcing I/O points and memory elements from a remote terminal. Linking a PLC into a control hierarchy containing several sizes of PLC and computer.

Monitoring data and alarms, etc. via printers or Operator Interface Units (OIUs).

*PLC CommunicationsSerial Communications

PLC communications facilities normally provides serial transmission of information.

Common Standards

RS 232

Used in short-distance computer communications, with the majority of computer hardware and peripherals. Has a maximum effective distance of approx. 30 m at 9600 baud.

*PLC CommunicationsLocal Area Network (LAN)

Local Area Network provides a physical link between all devices plus providing overall data exchange management or protocol, ensuring that each device can talk to other machines and understand data received from them.

LANs provide the common, high-speed data communications bus which interconnects any or all devices within the local area.

LANs are commonly used in business applications to allow several users to share costly software packages and peripheral equipment such as printers and hard disk storage.

*PLC CommunicationsRS 422 / RS 485

Used for longer-distance links, often between several PCs in a distributed system. RS 485 can have a maximum distance of about 1000 meters.

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*SpecificationsSeveral factors are used for evaluating the quality and performance of programmable controllers when selecting a unit for a particular application. These are listed below.

NUMBER OF I /O PORTS

This specifies the number of I/O devices that can be connected to the controller. There should be sufficient I/O ports to meet present requirements with enough spares to provide for moderate future expansion.

Selecting a PLCCriteria

Number of logical inputs and outputs. Memory Number of special I/O modules Scan Time Communications Software

*SpecificationsOUTPUT-PORT POWER RATINGS

Each output port should be capable of supplying sufficient voltage and current to drive the output peripheral connected to it.

SCAN TIME

This is the speed at which the controller executes the relay-ladder logic program. This variable is usually specified as the scan time per 1000 logic nodes and typically ranges from 1 to 200 milliseconds.

*Specifications

MEMORY CAPACITY

The amount of memory required for a particular application is related to the length of the program and the complexity of the control system. Simple applications having just a few relays do not require significant amount of memory. Program length tend to expand after the system have been used for a while. It is advantageous to a acquire a controller that has more memory than is presently needed.

Karakteristik PLC:

**MODUL INPUT/OUTPUT PLC PADA DASARNYA ADALAH ANTARMUKA/INTERFACE YANG MENGHUBUNGKAN PLC DENGAN PIRANTI INPUT/OUTPUT EKSTERNAL, MELALUI SENSOR-SENSOR YANG TERHUBUNG KE MODUL INI , PLC MEMBACA BESARAN-BESARAN FISIK (POSISI,GERAKAN,LEVEL,ARUS,TEGANGAN) YANG TERDAPAT PADA SUATU PROSES ATAU MESIN .

SECARA FISIK INPUT/OUPUT MODUL TERPISAH DARI MODUL CPU . HAL INI TERJADI UNTUK MENJAGA AGAR KERUSAKAN PADA INPUT/OUTPUT TIDAK MENYEBABKAN TERJADINYA HUBUNG SINGKAT PADA UNIT CPU.ISOLASI RANGKAIAN MODUL DARI CPU INI UMUMNYA MENGGUNAKAN RANGKAIAN OPTOCOUPLERMODUL I/O DISKRIT DAN MODUL I/O ANALOG

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**INPUT KE DAN OUPUT DARI SUATU PLC ADALAH PENTING UNTUK MEMANTAU DAN MENGONTROL SUATU PROSES. BAIK INPUT MAUPUN OUTPUT DAPAT DIKELOMPOKKAN MENJADI 2 JENIS DASAR YAITU: LOGIKA ATAU KONTINU OUTPUT KE AKTUATOR MEMUNGKINKAN SUATU PLC MENYEBABKAN SESUATU TERJADI DALAM PROSES CONTOH AKTUATOR KATUP KUMPARAN: OUPUT YANG DAPAT MENSWITCH SUATU ALIRAN HIDROLIK ATAU PNEUMATIKLAMPU: OUTPUT YANG DAPAT DIAKTIFKAN SECARA LANGSUNG DARI OUTPUT PLC BOARDMOTOR STARTER:MOTOR YANG MENARIK SEJUMLAH ARUS YANG BESAR KETIKA START, OLEH KARENA ITU DIBUTUHKAN MOTOR STARTER, YANG PADA PRINSIPNYA ADALAH RELAY-RELAY YANG BESARMOTOR SERVO: SUATU OUTPUT KONTINU DARI PLC DAPAT MEMERINTAHKAN SUATU KECEPAT AN VARIABEL ATAU POSISI

OUPUT DARI PLC BIASANYA BERUPA RELAY TETAPI BISA JUGA KOMPONEN ELEKTRONIKA SOLID STATE SEPERTI TRANSISTOR UNTUK OUTPUT DC ATAU TRIAC UNTUK OUTPUT AC. OUTPUT KONTINU MEMBUTUHKAN MODUL OUTPUT KHUSUS ( MODUL ANALOG ) DENGAN DIGITAL TO ANALOG CONVERTER INPUT BERASAL DARI SENSOR YANG MENGUBAH FENOMENA FISIK KE SINYAL LISTRIK

CONTOH SENSOR : PROXIMITY SWITCH : MENGGUNKAN INDUKTANSI , KAPASITANSI ATAU CAHAYA UNTUK MENDETEKSI OBYEK SECARA LOGIKASWITCH/SAKLAR : MEKANISME MEKANIK YANG AKAN MEMBUKA ATAU MENUTUP KONTAK LISTRIK UNTUK SUATU SINYAL LOGIKAPOTENSIOMETER : MENGUKUR POSISI ANGULAR SECARA TERUS MENERUS MENGGUNAKAN TAHANAN

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A discrete data point is one with only two statesonandoff. Process switches, pushbutton switches, limit switches, and proximity switches are all examples of discrete sensing devices. In order for a PLC to be aware of a discrete sensors state, it must receive a signal from the sensor through adiscrete inputchannel. Inside the discrete input module is (typically) a light-emitting diode (LED) which will be energized when the corresponding sensing device turns on. Light from this LED shines on a photo-sensitive device such as a phototransistor inside the module, which in turn activates abit(a single element of digital data) inside the PLCs memory. This opto-coupled arrangement makes each input channel of a PLC rather rugged, capable of isolating the sensitive computer circuitry of the PLC from transient voltage spikes and other electrical phenomena capable of causing damage.

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Indicator lamps, solenoid valves, and motor contactors (starters) are all examples of discrete control devices. In a manner similar to discrete inputs, a PLC connects to any number of different discrete final control devices through adiscrete output channel. Discrete output modules typically use the same form of opto-isolation to allow the PLCs computer circuitry to send electrical power to loads: the internal PLC circuitry driving an LED which then activates some form of photosensitive switching device. Alternatively, small electromechanical relays may be used to interface the PLCs output bits to real-world electrical control devices.An important concept to master when working with DC discrete I/O is the distinction betweencurrent-sourcingandcurrent-sinkingdevices. The terms sourcing and sinking refer to the direction of current (as denoted by conventional flow notation) into or out of a devices control wire. A device sending (conventional flow) current out of its control terminal to some other device(s) is said to besourcingcurrent, while a device accepting (conventional flow) current into its control terminal is said to besinkingcurrent.To illustrate, the following illustration shows a PLC output channel issourcingcurrent to an indicator lamp, which issinkingcurrent to ground:

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Dari gambar 1 sampai gambar 3, terlihat bahwa secara fisik rangkaian pada modul ini terpisah dari rangkaian internal (CPU). Isolasi rangkaian ini menggunakan optocoupler dengan dua buah diode pemancar yang dipasang antiparalel. Hal ini dilakukan untuk tujuan fleksibilitas penyambungan terminal input dengan catu daya penggerak sensor atau saklar yang terhubung. Dalam hal ini, terminal common pada modul dapat dihubungkan balk dengan polaritas yang lebih positif atau lebih negatif dari catu dayanyaBesar arus yang mengalir di dalam sebuah terminal input ketika sebuah saklar tertutup umumnya berada dalam satuan miliampere (tipikalnya adalah 7 miliampere). Arus sebesar ini telah cukup untuk menggerakkan basis transistor pada optocoupler menjadi ON. Jika menggunakan sumber tegangan yang lebih kecil dari yang telah ditentukan oleh vendor PLC yang dipakai maka akan terjadi situasiundercurrent,yaitu arus yang mengalir pada modul tidak dapat menggerakan basis transistor pada optocoupler tersebut

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output Relayoutput PLC jenis relay adalah yang paling fleksibel penggunaannya karena dapat menggerakkan beban AC maupun DC. kelemahannya terletak pada tanggapanswitching-nyayang relatif lambat (sekitar 10 ms ), dan akan mengalami kerusakan setelah beberapa juta siklusswitching.Gambar 4 rangkaian internal output PLC Jenis relayBesar rating arus untuk setiap terminal umumnya tidak boleh melebihi 2 A untuk tegangan 220 volt (untuk lebih jelasnya dapat dilihat pada manual PLC yang digunakan). Bila batas besar rating arus ini dilampaui, akan menimbulkan kerusakan pada modul output nya. Jika keluaran yang akan dikontrol merupakan beban yang relatif besar (mengalirkan arus dengan jumlah besar) maka akan lebih aman jika output relay ini mengontrol beban tersebut lewat relay luar.

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output transistoroutput PLC jenis transistor, beban yang dapat dikontrol terbatas pada beban-beban jenis DC saja. (besar arus yang bisa dilewatkan umumnya adalah 1 A, dengan waktu respons kurang dari 1 ms)Berdasarkan transistornya, ada dua jenis output PLC ini: (1) jenis NPN dan (2) jenis PNP. Pada prinsipnya kedua jenis keluaran ini adalah sama, yaitu dapat mengalirkan arus atau daya dalam satu arah saja. Ada dua jenis mode operasi transistor ini: (1) transistor digunakan sebagai penguat linier, dan (2) transistor digunakan sebagai saklar. Dalam rangkaian internal PLC, Iransistor dioperasikan sebagai saklar, yaitu dengan cara mengoperasikan pada daerah jenuhnya.Perlu ditekankan di sini, walaupun transistor ini berlaku sebagai saklar, tetapi secara praktis akan selalu ada drop tegangan pada saklar ini (antara kaki collector terhadap emiter) yang besarnya berkisar antara 1-2 volt Gambar 5 rangkaian internal output PLC Jenis Transistorjenis keluaran transistor NPN. Dari gambar, terlihat bahwa terminal common pada modul output harus selalu dihubungkan dengan sumber tegangan positif (ingat, transistor dalam operasinya hanya akan mengalirkan arus dari collector ke emiter jika tegangan collector lebih positif dari tegangan emitterModul output PLC jenis PNP memiliki prinsip kerja kebalikan dari jenis NPN yang telah dibahas di atas.

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Gambar 5 rangkaian internal output PLC Jenis Transistorjenis keluaran transistor NPN. Dari gambar, terlihat bahwa terminal common pada modul output harus selalu dihubungkan dengan sumber tegangan positif (ingat, transistor dalam operasinya hanya akan mengalirkan arus dari collector ke emiter jika tegangan collector lebih positif dari tegangan emitterModul output PLC jenis PNP memiliki prinsip kerja kebalikan dari jenis NPN yang telah dibahas di atas.

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output jenis triacoutput Triac terbatas pada beban jenis AC (besar arus yang bisa dilewatkan umumnya adalah 1 A, dengan waktu respons kurang dari 1 ms)Triac adalah sebuah komponen semikonduktor yang berfungsi mengalirkan arus bolak-balik. Arus yang dialirkan dikontrol oleh terminal gate pada triac tersebut dalam modul output PLC jenis ini, triac digunakan untuk memerlukan gerakkan beban-beban AC lewat rangkaian internalnya

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Selain dapat mengolah sinyal digital, PLC juga dapat mengolah sinyal analog.Modul ini biasanya didesain untuk membaca sinyal-sinyal standard industri yakni 0 5 V, 10 V, atau 4 20 mA. Untuk menggunakan analog input, modul ini harus dihubungkan ke rangkaian PLC dan ditentukanUnit No.-nya. Unit No. ini ditentukan dengan cara mengatur skrupMach No.di depan Modul Analog Unit. Skrup Mach No. ini ada 2 buah: satu skrup puluhan (x10) dan satu skrup satuan (x10). Jika ingin membuat modul ini memiliki Unit No. 12, putar skrup puluhan ke angka 1 dan skrup satuan ke angka 2. Selain itu, di IO Table dan Unit Setup pada CX-Programmer juga harus diberi Unit No. yang sama. Ingat, Unit No. modul ini tidak boleh sama dengan modul lain karena akan bertabrakan pengalamatan memorinya

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*I/O ModuleDC / AC OUTPUT MODULEFROM PROCESSORTOOUTPUTDEVICE

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*I/O CircuitsDIFFERENT TYPES OF I/O CIRCUITS

1. Pilot Duty OutputsOutputs of this type typically are used to drive high-current electromagnetic loads such as solenoids, relays, valves, and motor starters.

These loads are highly inductive and exhibit a large inrush current.

Pilot duty outputs should be capable of withstanding an inrush current of 10 times the rated load for a short period of time without failure.

*I/O Circuits2. General - Purpose OutputsThese are usually low- voltage and low-current and are used to drive indicating lights and other non-inductive loads. Noise suppression may or may not be included on this types of modules.

3. Discrete InputsCircuits of this type are used to sense the status of limit switches, push buttons, and other discrete sensors. Noise suppression is of great importance in preventing false indication of inputs turning on or off because of noise.

modul analog output digunakan untuk mengeluarkan sinyal analog dari PLC. Sinyal analog yang dapat dikeluarkan umumnya berada dalam rentang sinyal-sinyal standard industri seperti 4 20 mA. Sama seperti pada modul analog input, modul analog output juga harus diatur Unit No. nya terlebih dahulu untuk menentukan pengalamatan memorinya. Selain itu, resolusidan jenis outputnya juga bisa ditentukan (tegangan atau arus).**

*I/O Circuits4. Analog I/O

Circuits of this type sense or drive analog signals.

Analog inputs come from devices, such as thermocouples, strain gages, or pressure sensors, that provide a signal voltage or current that is derived from the process variable. Standard Analog Input signals: 4-20mA; 0-10V

Analog outputs can be used to drive devices such as voltmeters, X-Y recorders, servomotor drives, and valves through the use of transducers. Standard Analog Output signals: 4-20mA; 0-5V; 0-10V

*I/O Circuits5. Special - Purpose I/O

Circuits of this type are used to interface PLCs to very specific types of circuits such as servomotors, stepping motors PID (proportional plus integral plus derivative) loops, high-speed pulse counting, resolver and decoder inputs, multiplexed displays, and keyboards.

This module allows for limited access to timer and counter presets and other PLC variables without requiring a program loader.

*PLCINPUTSOUTPUTSMOTORLAMPCONTACTORPUSHBUTTONS

*P. B SWITCHINPUT MODULEWIRING DIAGRAMLADDER PROGRAM I:2 0I= InputModuleslot # in rackModuleTerminal #Allen-Bradley 1746-1A16Address I:2.0/0

*N.OC L2 L1 L1 L2 OUTPUT MODULEWIRING MOTORCONTACTORO:40CONTACTORLADDER PROGRAM L1 L2FIELD WIRINGSOLENOIDVALVESLAMPBUZZER

*Discrete InputA discrete input also referred as digital input is an input that is either ON or OFF are connected to the PLC digital input. In the ON condition it is referred to as logic 1 or a logic high and in the OFF condition maybe referred to as logic o or logic low.

*OFFLogic 0INPLC

InputModule24 V dcOFFLogic 1INPLC

InputModule24 V dc

*TankLevel TransmitterAn analog input is an input signal that has a continuoussignal. Typical inputs may vary from 0 to 20mA, 4 to 20mAor 0 to10V. Below, a level transmitter monitors the level of liquid in the tank. Depending on the level Tx, the signal to thePLC can either increase or decrease as the level increases or decreases.Analog Input

*OUTPLC

Digital OutputModuleLampA discrete output is either in an ON or OFF condition. Solenoids, contactors coils, lamps are example of devices connected to the Discrete or digital outputs. Below, the lamp can be turned ON or OFF by the PLC output it is connected to.Digital Output

*OUTPLC

AnalogOutputModuleAn analog output is an output signal that has a continuoussignal. Typical outputs may vary from 0 to 20mA, 4 to 20mAor 0 to10V.Analog OutputEPPneumatic control valveSupply airElectric to pneumatic transducer0 to 10V

BINEROCTALDESIMALHEKSADESIMAL**

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Example: What is 11112in Decimal?The "1" on the left is in the "222" position, so that means 1222 (=8)The next "1" is in the "22" position, so that means 122 (=4)The next "1" is in the "2" position, so that means 12 (=2)The last "1" is in the units position, so that means 1Answer: 1111 = 8+4+2+1 = 15 in DecimalExample: What is 10012in Decimal?The "1" on the left is in the "222" position, so that means 1222 (=8)The "0" is in the "22" position, so that means 022 (=0)The next "0" is in the "2" position, so that means 02 (=0)The last "1" is in the units position, so that means 1Answer: 1001 = 8+0+0+1 = 9 in Decimal

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**Example: What is 1.12in Decimal?The "1" on the left side is in the units position, so that means 1.The 1 on the right side is in the "halves" position, so that means 1(1/2)So, 1.1 is "1 and 1 half" = 1.5 in DecimalExample: What is 10.112in Decimal?The "1" is in the "2" position, so that means 12 (=2)The "0" is in the units position, so that means 0The "1" on the right of the point is in the "halves" position, so that means 1(1/2)The last "1" on the right side is in the "quarters" position, so that means 1(1/4)So, 10.11 is 2+0+1/2+1/4 = 2.75 in Decimal

Both Decimal and Binary numbers use a positional weighting system, eg: 10102 = 1x23+0x22+1x21+0x20 = 1x8 + 0x4 + 1x2 + 0x1 = 1010

decimal100 (102)10 (101)1 (100)403400 + 0 + 3

binary8 (23)4 (22)2 (21)1 (20)10018 + 0 + 0 + 1

Multiply each 1 bit by the appropriate power of 2 and add them together.100000112 = .10 ?

1010011002 = 10 ?

??128643216842110000011101001100

Number Representation - Binary to decimalA decimal number can be converted to binary by repeated division by 2

15510 = 100110112

number/2remainder155771Least Significant Bit77381381901991941420210101Most Significant bit

An alternative way is to use the placement method

128 goes into 155 once leaving 27 to be placed

So 64 and 32 are too big (make them zero)16 goes in once leaving 11

and so on

1286432168421

1

1001

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Hexadecimal and OctalWriting binary numbers as strings of 1s and 0s can be very tediousOctal (base 8) and Hexadecimal (base 16) notations can be used to reduce a long string of binary digits.

Notice that hexadecimal requires 15 symbols (each number system needs 0 base-1 symbols) and therefore A F are used after 9.

octal512 (83)64 (82)8 (81)1 (80)1207512 + 128 + 7

hexadecimal256 (162)16 (161)1 (160)1AF256 + 160 + 15

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Each octal digit corresponds to 3 binary bitsTo convert a binary string: 10011101010011

Split into groups of 3: 010 011 101 010 011 2 3 5 2 3

Thus 100111010100112 = 235238

binaryoctal00000011010201131004101511061117

Each hex digit corresponds to 4 binary bitsTo convert a binary string: 10011101010011

Split into groups of 4: 0010 0111 0101 0011

Thus 100111010100112 = 16 ?

binaryhex0000000011001020011301004010150110601117

binaryhex10008100191010A1011B1100C1101D1110E1111F

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CharactersThree main coding schemes used: ASCII (widespread use), EBCDIC (not used often) and UNICODE (new)ASCII table (in hex) :

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Other codes exist for specific purposesGray codes provide a sequence where only one bit changes for each incrementAllows increments without ambiguity due to bits changing at different times.E.g. changing from 3 to 4, normal binary has all three bits changing 011 -> 100. Depending on the order in which the bits change any intermediate value may be created.

DecGray 00001001201130104110511161017100

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Kode digunakan untuk pengecekan data sesuai dengan urutan binerBiasa untuk piranti yang menggunakan posisi angularKonsepnya adalah bilangan binernya hanya berubah satu setiap naik atau turunIni mempermudah mendeteksi terjadinya kesalahan setiap perubahan**

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BIT PARITY DAPAT DITAMBAHKAN KE DATA SEBAGAI PENGECEKAN KESALAHAN SEDERHANA DATA YANG DIKIRIM,JIKA DATA YANG DIKIRIM TERJADI KESALAHAN AKAN DIKIRIM ULANG ATAU DIABAIKAN PARITY DITAMBAHKAN PADA DAA HINGGA 8 ATAU 9 BITPARITY EVEN DAN ODD**

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Simple gatesANDORNOTFunctionality can be expressed by a truth tableA truth table lists output for each possible input combinationPrecedenceNOT > AND > ORF = A B + A B = (A (B)) + ((A) B)

Additional useful gatesNANDNORXORNAND = AND + NOTNOR = OR + NOTXOR implements exclusive-OR functionNAND and NOR gates require only 2 transistorsAND and OR need 3 transistors!

Proving NAND gate is universal

Proving NOR gate is universal

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Integration levelsSSI (small scale integration)Introduced in late 1960s1-10 gates (previous examples)MSI (medium scale integration)Introduced in late 1960s10-100 gatesLSI (large scale integration)Introduced in early 1970s100-10,000 gatesVLSI (very large scale integration)Introduced in late 1970sMore than 10,000 gates

Logical functions can be expressed in several ways:Truth tableLogical expressionsGraphical formExample:Majority functionOutput is one whenever majority of inputs is 1We use 3-input majority function

3-input majority function

ABCF00000010010001111000101111011111Logical expression formF = A B + B C + A C

All three circuits implement F = A B function

Derivation of logical expression from a circuitTrace from the input to outputWrite down intermediate logical expressions along the path

Proving logical equivalence: Truth table method

A BF1 = A BF3 = (A + B) (A + B) (A + B)0 0 0 00 1 0 01 0 0 01 1 1 1

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Proving logical equivalence: Boolean algebra methodTo prove that two logical functions F1 and F2 are equivalentStart with one function and apply Boolean laws to derive the other functionNeeds intuition as to which laws should be applied and whenPractice helpsSometimes it may be convenient to reduce both functions to the same expressionExample: F1= A B and F3 are equivalent

A simple logic design process involvesProblem specificationTruth table derivationDerivation of logical expressionSimplification of logical expressionImplementation

3-input majority function

ABCF00000010010001111000101111011111SOP logical expressionFour product termsBecause there are 4 rows with a 1 output

F = A B C + A B C + A B C + A B C

Two basic methodsAlgebraic manipulationUse Boolean laws to simplify the expressionDifficult to useDont know if you have the simplified formKarnaugh map (K-map) methodGraphical methodEasy to useCan be used to simplify logical expressions with a few variables

Majority function example

A B C + A B C + A B C + A B C =

A B C + A B C + A B C + A B C + A B C + A B C

We can now simplify this expression as

B C + A C + A B

A difficult method to use for complex expressionsAdded extra

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Note the order

Simplification examples

First and last columns/rows are adjacent

Minimal expression depends on groupings

No redundant groupings

Dont cares simplify the expression a lot

Using NAND gatesGet an equivalent expression

A B + C D = A B + C DUsing de Morgans law

A B + C D = A B . C DCan be generalizedMajority function

A B + B C + AC = A B . BC . ACIdea: NAND Gates: Sum-of-Products, NOR Gates: Product-of-Sums

Majority function

Combinational circuitsOutput depends only on the current inputsCombinational circuits provide a higher level of abstractionHelp in reducing design complexityReduce chip countWe look at some useful combinational circuits

*PROGRAMMINGNormally Open(NO)Normally Closed(NC)Power flows through these contacts when they are closed. The normally open (NO) is true when the input or output status bit controlling the contact is 1. The normally closed (NC) is true when the input or output status bit controlling the contact is 0.

*CoilsCoils represent relays that are energized when power flows tothem. When a coil is energized it causes a correspondingoutput to turn on by changing the state of the status bit controlling the output to 1. That same output status bit maybe used to controlnormally open or normally closed contact anywhere in the program.

*BoxesBoxes represent various instructions or functions that areExecuted when power flows to the box. Some of these Functions are timers, counters and math operations.

*AND OPERATIONEach rung or network on a ladder program representsa logic operation. In the rung above, both inputs A and Bmust be true (1) in order for the output C to be true (1).RungA BC

*OR OPERATIONIn the rung above, it can be seen that either input A or Bis be true (1), or both are true, then the output C is true (1).RungA BC

*NOT OPERATIONIn the rung above, it can be seen that if input A is be true (1),then the output C is true (0) or when A is (0), output C is 1.RungA C

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****Octal group into lots of 3 binary digits starting from the LSBHex group into lots of 4 binary digits starting from the LSB****************************