Winter 23 Past Paper, PDF

# Winter - 23 ## Q.1 Attempt any 5 of the Following a. State need of industrial automation - Need - To fulfill the demand of product at right time. - To reduce the human error & involvement of human beings in a process. - For better productivity. - For better control system. - For better...

# Winter - 23 ## Q.1 Attempt any 5 of the Following a. State need of industrial automation - Need - To fulfill the demand of product at right time. - To reduce the human error & involvement of human beings in a process. - For better productivity. - For better control system. - For better quality. - For reduced manpower - For reducing cost of product. - To improve work safety. b. Enlist types of automation - Types of automation. - Fixed automation. - Flexible automation. - Programmable automation. - Integrated automation. c. List any 4 output devices used for PLC - Output Devices. - Relay - DC motor - Conveyor belt - Solenoid operated valve - Indicator lamp or light - Stepper motor - Servo motor. d. Explain the concept of sinking with neat sketch. - Concept of sinking | I/P device | 0 | Load | | ------------ | ----- | ----- | | 00 | 0 | 0 | | 01 | 0 | 0 | | 02 | 0 | 0 | | 03 | 0 | 0 | | 04 | 0 | 0 | | 05 | 0 | 0 | | 06 | 0 | 0 | | 07 | 0 | 0 | | Common | (-) | (-) | - PNP transistors are open collector, current sources, which interface to a sinking I/P module. - In sinking devices current flow into devices terminals in the module. e. Define and explain SCAN cycle. - Define scan cycle - The scan cycle of a PLC is defined as a list of repeatable list of executable tasks called as 'scan cycle'. - Explanation: | Stage | Description | | ----------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Read Inputs | At this stage PLC reads the input signals on all input terminals in a scanning manner and stores each input state in the input image. The input devices are sensors, switches, actuators, etc.. | | Execute Program | PLC executes a program one instruction at a time from left to right and from top to bottom, using the input data. | | Output update | The operation result of the program during the execution phase are stored in the output image resistor. | | Diagnostic Communication. | The communicationes only necessary information to a control network such as modebus or ethernet i/p. This entire process is in the scan cycle. | ## F. Write PLC program for AND gate. - AND Gate - Symbol - A &#x20;B = Y=A.B. - Truth table: | A | B | Y:AB | | - | - | ----- | | 0 | 0 | 0 | | 0 | 1 | 0 | | 1 | 0 | 0 | | 1 | 1 | 1 | - Ladder Diagram: - A (1:011) B (1:012) Y (0:012) ## F. List any 4 benefits of SCADA - Benefits of SCADA - Increased productivity of the operating personnel. - Improved safety of the system due to better information. - Improved the control. - Protection of plant equipment. - Safeguarding the environment from a failure of the system due to optimization of plant operation. # 2.2 Attempt any 3 of the following. a. Explain types of a digital control used in automation with a suitable example. - Supervisory Control - Black diagram  - Working: - Supervisory control emerged as an intermediate step wherein the computer was used to monitor the operation of analog control loop & to determine appropriate set points. - A single computer can monitor many control loops & use appropriate software to optimize set point for the best overall plant operation. - If the computer failed, the analog loop keeps the process running using the last setpoint until the computer comes back online. - Figure shows how a supervisory computer would be connected to an analog heat control system. ADC & DAC provide an interface between analog signals and a computer. - Direct digital Control - Block Diagram  - Explanation - Figure shows a full computer control system, where the operations of the controller have been replaced by software in the computer. - The ADC & DAC provides interface with the process measurement & control action. - The computer I/P digital representation of temperature 'NT' as an analog & digital conversion of voltage 'VT'. Error detection & controller action are determined by software. - The computer provides a/p directly to the heater, via digital representation 'Ne' which is converted to the excitation voltage 'Va' by the DAC. - This DDC system lets the computer perform the error detection & controller function. # b. Classify PLC. Also write criteria for selecting PLC for specific application. - Type of application. PLC | Type of PLC| Based on Size (No. of I/O) | Based on Hardware Setup | Based on Power Supply | | ---------- | ----------------------------- | --------------------------- | ----------------------- | | Nano PLC | Nano PLC | Compact | With SMPS | | Micro PLC | Micro PLC | Modular | Without SMPS | | Small PLC | Small PLC | | | | Medium PLC | Medium PLC | | | | Large PLC | Large PLC | | | | Very Large PLC | Very Large PLC | | | - Criteria: - Control requirements: - No. of I/O - Types of I/O - Industry standard - Environmental conditions - Power supply - Redundancy & backup - Memory & programming requirement - Compact or modular PLC - Instruction set / CPU - PLC scan time. - Sinking & sourcing PLC - Manufacture Support & backup # c. Explain FBC and SFC PLC programming language with suitable examples. - Functional Block Diagram (FBD) - The primary concept behind FBD is data-flow. In this instruction are composed of operational blocks, each block has one or more I/P and O/P. - Example: Simple Comparison example ![[Image showing FBD diagram]] - Sequential function Chart (SFC) -This language is used for performing simultaneously operations required for controller in complex machine process. - E.g. ![Image showing SFC diagram] # d. Draw function block diagram of ON-delay timer. Give the function of done (DN), enable (EN), and timer time (TT) bit of timer. - Black diagram. ![Image showing timer block diagram] - Function | Sr. No. | Output bit | Is set when | Remain set until the use of the following rung condition. | | -------- | ---------- | ------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------- | | 1 | Timer done bit (CDN) | Accumulator value is equal to or greater then the preset value. | Rung condition becomes false. | | 2 | Timer enable bit (CEN) | Rung conditions are true and the preset valve. | Rung condition become false. | | 3 | Timer timing bit (CTT) | Rung condition are true and the accumulator value is when the done bit becomes false or less than the preset is set value. | Rung condition become false. | # Q.3. Attempt any 3 of the following. a. List types of automation and compare them (any 3 points) | Parameter | Fixed | Flexible | Programmable | | --------------------|-------------------|--------------------|----------------------- | | Production | Highly suitable for mass production | Individual or low volume production | Used for batch production | | | | Can be many factored | | | Production Rate | High rate of production | Low production rate | Medium production rate | | Flexibility | No flexibility is allowed | Higher flexible change of product | Change of product can be varied in any design. | | Setup time | No setup time is needed as tooling is fixed | Set minimum setup time for tooling | Manufactured setup time, change w/r.t batch | | Application | Assembly line of automotive vehicles | Robot designed for assembly | Factory automation | # d. Draw and explain memory organization of PLC - Memory organization in PLC. - To understand the organization of memory in PLC, think the program file and data file like a two-drawer file cabinet, wherein program files are in one drawer and data files are in the other drawer as shown in the figure. ![Image showing memory organization] - Program files: - The PLC processor stores the system information and user program in one group of files called program files. - There are 256 program files available per project file. - As shown in the figure, all 256 files are orderly arranged *in program file folder*. - File 0 (Sys0) - Contain system configuration information. - File 1 (Sys1) - Contain system configuration information. - File 2 (LAD2) - Contains main ladder program. - File 3 (LAD3) to File 255 (LAD 255) - Contain subroutines. - Data files: - The PLC memory stores the data which is required to solve the user program in one group of files called *data files*. - There are 256 files (0 to 255) orderly arranged *in data file folder*. - Data file consists of 9 default data files (i.e., 0 to 8) and user-defined data files are 247 (i.e., 9 to 255). # Write and explain logical addressing format for input output in PLC. | File Type | Identifier | Logic address | File No. | | ---------- | ---------- | -------------- | -------- | | Output | 0 | 0:0 to 0:30 | 0 | | Input | I | I:0 to I:30 | 1 | | Status | S | S:0 to S:30 | 2 | | Bit | B | B3:0 to B3:255 | 3 | | Timer | T | T4:0 to T4:255 | 4 | | Counter | C | C5:0 to C5:255 | 5 | | Control | R | R6:0 to R6:255 | 6 | | Integer | N | N7:0 to N7:2:55 | 7 | | Float | F | F8:0 to F8:255 | 8 | | Network | X | X9:0 to X9:255 | 9 | | User Define | X | X10:0 to X10:255 | 10 | - Basis addressing elements: - **Type:** This type determines the I/P & O/P or other type of file. - **Slot:** The slot no. indicates the physical location of I/O module. - **Word & Bit:** Word & Bit are used *to identify* the actual connection in particular I/O module. # Write a ladder program for traffic light control system with following conditions. 1. Red & green light ON for 35 sec each. 2. Yellow light ON for 5 sec as soon as red light is OFF. 3. Green light is ON as soon as yellow light is OFF. 4. The process types continues until the OFF button is pressed. ![Image showing traffic light ladder program] # Draw basic architecture of SCADA & explain in brief. - Monolithic SCADA system ![Image showing monolithic SCADA architecture] - It is the 1st generation SCADA system, which uses micro-computers for controlling. - It is limited for a single system and is able to communicate with other systems. - Remote Terminal Units (RTU's) connected to SCADA master or PLC are used to collect the information about sensors through PLC & generate the alarms from abnormal conditions, and display on HMI. - Distributed SCADA System ![Image showing Distributed SCADA architecture] - This is the 2nd generation SCADA system. In this system, multiple systems are connected to each other by using a Local Area Network (LAN). - Control functions are distributed among these systems. - The communication protocol used by the individual station for sharing information is designed by developers and is not standardized or secure. - Networked SCADA System ![Image showing Networked SCADA architecture] - This is the 3rd generation of SCADA system. - All nodes in this system are in a network through a Wide-Area Network.(WAN). - Information is shared between the nodes by using Ethernet or fiber optics communication. - In this system, a single supervisor can handle many distributed systems in the network.. # Attempt any 3 of the following. a. State need of PLC over hardwired relay logic. b. Write any two benefits & two limitations of PLC in industrial automation. - **Characteristics:** | Feature | Relay based control | PLC Based control | | --------------------- | ------------------------- | --------------------- | | Nature of control | Handwired, cumbersome | Software based, easy | | Complex operation | Difficult to realize | Easy to realise | | Modification | Difficult to rewire | Easy to program & reprogram | | Controller Size | Large | Compact | | Troubleshooting | Difficult to diagnose faults | Easy to diagnose fault | - **Benefits:** - Lower operating cost - Reduced factory load time. - Increased production output. - Improved quality. - **Limitations:** - Processing power is low compared to industrial PCs. - Programming complexity. - Scalability Issues - Cost-effectiveness for many operations. # b. State any 4 I/p devices used with PLC. Also write their function. - Limit switch - Function: Detects the physical movement or position of the object. - Output: Provides binary I/P signals to PLC. - Photoelectric sensor. - Function: Detects an object, present/absence or change in light intensity. - Temp. Sensor. - Function: Measures temperature or processes or equipment. - Proximity sensor - Function: Detects the presence or absence of objects without physical contact. # c. List do's and don'ts for PLC installation. - **Do's:** - Take wiring diagram from the manufacturer. - Be careful about power wiring as well as I/O wiring. - Find out if PLC is powered by AC or DC voltage. - If it is powered by 120VAC or 240VAC, read the specifications for sourcing & sinking I/O solps. - Connect wire from a discrete I/P such as a switch & push button to the actual I/P terminal. - Do provide fuses for devices such as solenoids that can cause a short in them to protect I/P cards. - Use twisted pair shielded cable for analog I/P cards. - **Don'ts:** - Avoid using 230V devices for I/P, use transformers to step them down to 110V level or prefer 24V I/P & O/P. - Avoid hand-written labels, use printed wrap around labels. # d. A coal handling plant has 3 coal conveyors C1 C2 & C3. C1 is feed from output of crusher, C2 is mid belt, and C3 push coal to bunker. The requirement of plant operation is as follows. 1. C1 and C2 will be ON when C3 is ON. 2. C1 is ON only when C2 & C3 is ON. 3. C1 trips when C2 trips but C3 is ON. 4. C1 trips when C3 trip but C2 is ON. 5. C1 trips when C2 & C3 trips. - Design a ladder diagram for above condition. - Input - PB to start conveyor C1 - PB1 - I:010 - PB to stop conveyor C1 - PB2 - I:011 - PB to start conveyor C2 - PB3 - I:012 - PB to stop conveyor C2 - PB4 - I:013 - PB to start conveyor C3 - PB5 - I:014 - PB to stop conveyor C3 - PB6 - I:015 - Output - Conveyor C1 - 0:010 - Conveyor C2 - 0:011 - Conveyor C3 - 0:012 - Ladder diagram ![Image showing coal handling ladder diagram] # c. Write down the steps for creating a SCADA screen for a simple object. - Winter - 22 (Q.6.B) - Developing SCADA application with a simple system. - Creating new I/O server and I/O device. - In citect project editor, communication express wizard is used to create new I/O server, which is linked with *KEPServer EX, V4 driver*. - A new I/O device is created, which is linked with *Allen Bradlety PLC driver*. - The linking I/O server and I/O device enables the SCADA to access real-time data from PLC through OPC server. - Creating variable tags and graphics. - In citect project editor, variable tags are created with specific tags name and data types. - These are linked with an I/O device and I/O server. - The variable tags hold real-time data acquired from PLC. - To develop a required graphic, *Citect SCADA graphic builder platform* is used. - Configuring OPC DAI. - KEPServer EX is an OPC server, which acts as a link between a SCADA client and a PLC-based application. - It serves live data to a SCADA client, which it had acquired from PLC. # Explain AC discreet I/P module w.r.t following points: 1) Block Diagram 2) Function of each block 3) Wiring diagram 4) Any 4 specification - Block Diagram: ![Image showing block diagram for AC discrete I/P module] - Function of each block: - The I/P circuit has two basic sections, the *power & logic section*. - An optical isolator is used to provide electrical isolation between the field winding & PLC back plane to internal circuitry. - A bridge rectifier is used to convert AC signal voltage into DC voltage. - The I/P turns on/off, indicating the status of the I/P device. - A zener diode regulates the voltage level. - Wiring Diagram ![Image showing wiring diagram for AC discrete I/P module] - Any 4 specification - Module type: AC discrete input module. - Input type: AC voltage - No. of I/P: 8 / 16 / 32 (Dependent on the module.) - Input voltage range: 100-240VAC. - Frequency range: 50/60Hz. # b. Write PLC program for stepper motor control using suitable system design for the same. - Summer - 24 (Q.5. B) - Input: - 1:011- Start PB - 1:012 - Stop PB - Output - PHA - 0:010 - PHB - 0:011 - PHC - 0:012 - PHD - 0:013 - Ladder diagram: - Timer On delay (EN) - Timer T4:0 - Time base 1.0 - Preset 2 - Accum 0 (DN) - PHA 0:010 - Timer on delay (EN) - Timer T4:1 - Time base 1.0 - Preset 2 - Accum 0 (DN) - PHB 0:011 - Timer on delay (EN) - Timer T4:2 - Time base 1.0 - Preset 2 - Accum 0 (DN) - PHC 0:012 - Timer on delay (EN) - Timer T4:3 - Time base 1.0 - Preset 2 - Accum 0 (DN) - PHD 0:013 ![Image showing ladder diagram for stepper motor control] # Attempt any 2 of the following. a. Write down counter instruction format. List and explain types of status bit of counter. - Summer - 24 (Q.5.C) # b. Explain concept of seal in circuit. Explain ladder diagram for seal in circuit with a suitable example. - Concept - A seal-in circuit is a method of maintaining current flow after a momentary switch (PB) has been pressed and released. - It is an electrical or logical control mechanism that maintains specific conditions, even after the initial trigger. - Ladder diagram - Motor Coil - M (0:011) - Start PB - 1:011 - Stop PB - 1:012 - Motor coil starter contact - 0:011 - Auxiliary Contact - M (0:010) ![Image showing ladder diagram of a seal-in circuit] - A seal-in circuit is an electrical or logical control mechanism that maintains specific conditions, even after the initial trigger. - When Start PB is pressed, the motor coil "M" gets energized and the motor is connected across the supply. - When start PB is released, supply to "M" is maintained through an auxiliary contact of "M." When Stop PB is pressed, "M" gets de-energized & the motor gets disconnected from the supply. - Examples: - Elevator control systems - Conveyor belt systems - Motor sequence control - Alarm systems # c. Draw & explain application of SCADA in water treatment plant. ![Image showing SCADA application in water treatment plant] - The central control room consists of a SCADA system, which takes integrated control on the entire plant. - The communication between SCADA & PLC control stations is high-speed real-time industrial Ethernet structure. - The plant communication network is divided into two components: control & onsite monitoring. - The water purification plant consists of 1. pump room, 2. chlorination room, 3. blow-down room, 4. sedimentation tank, 5. filter tank, 6. clean water, 7. secondary pump room. - Various SCADA-based system functional areas perform the following: 1. Control & consistent control of different processes. 2. Monitoring and event management 3. Alarm and event management 4. Database storage and processing 5. Maintain functions of the pump station 6. Data record facility with charts & plotters.