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Sunday, June 28, 2015

How to build a house in 2 days? Perth engineer invents world’s first robotic bricklayer

  • A robotic, fully-automated machine is being developed in Perth, a world-first that could raise the brick shell of a new home within two days.
It can work 24 hours, 365 days — compared to the human variety who can put in anywhere from four to six weeks of backbreaking work for a typical home.
Local inventor Mark Pivac, an aeronautic and mechanical engineer, said his interest in the idea of developing the robot was sparked during Perth’s bricklaying crisis of 2005.

“People have been laying bricks for about 6000 years and ever since the industrial revolution, they have tried to automate the bricklaying process,” Mr Pivac told Perth Now.
Robot brickies, the future of home building
Hadrian, the world's first automatic bricklayer Source: Supplied
“We’re at a technological nexus where a few different technologies have got to the level where it’s now possible to do it, and that’s what we’ve done.”
“Hadrian” the robot — named after the famous Roman defensive wall of antiquity — will be commercialised first in WA, then nationally and then globally.
Laying 1000 bricks per hour, it can work day and night, with the potential to erect 150 homes a year.
It works by creating a 3D computer-aided design (CAD) laying program of a house or structure, then calculates the location of every brick and creates a program that is used to cut and lay the bricks in sequence from a single, fixed location.
A 28m articulated telescopic boom goes to work and mortar or adhesive is delivered under pressure to the robotic laying head and applied to the brick which is then laid in the correct sequence as per the program. The robot de-hacks, measures, scans for quality and cuts to length the bricks and routs for electrical and other services.
Mr Pivac’s father was a mining surveyor so he grew up around measuring instruments from a young age.
Working for the Air Force, the engineer says he was “exposed to some pretty nice high technology, really modern manufacturing methods, instrumentation and a lot of complex systems”.
But it was while working in the area of computer-controlled machinery and witnessing the shortage of Perth bricklayers that the idea of a bricklaying robot really took hold.
‘Hadrian’ can raise the brick shell of a house in two days.
‘Hadrian’ can raise the brick shell of a house in two days. Source: Supplied
Nearly two billion bricks are manufactured a year in Australia, which added fuel to the fire of the inventor’s imagination.
The project has been 10 years in the making and Mr Pivac said it had been a team effort.
“We have absolutely nothing against bricklayers,” Mr Pivac said.
“The problem is the average age of bricklayers is going up and it’s difficult to attract new young people to the trade.”
This week, investment company DMY Capital Limited announced its conditional agreement to acquire 100 per cent of Australian robotic building technology company, Fastbrick Robotics, the company set up by Mr Pivac and his cousin, Mike Pivac.
DMY chairman Gabriel Chiappini said: “We were immediately excited by the opportunity and see an enormous potential both domestically and later globally.”
More than $7m has been spent on developing “Hadrian” to date.
Fastbrick Robotics said it had received significant support from both Federal government grants and major industry parties such as Brickworks Ltd, a group of Australian-owned companies centred on clay and concrete products.

Source:-  http://www.news.com.au/finance/real-estate/robot-brickie-perth-engineer-invents-worlds-first-robotic-bricklayer/story-fndbaln9-1227414734482

Thursday, June 25, 2015

Engineers Facts:- What Is a Programmable Logic Controller and Its Important ?


PLCs were introduced in the late 1960s by inventor Richard Morley to provide the same functions as relay logic systems. Relay systems at the time tended to fail and create delays. Technicians then had to troubleshoot an entire wall of relays to fix the problem.
1. The image above is an Allen-Bradley PLC rack, a common example of a PLC setup that includes a CPU, analog inputs, analog outputs, and dc outputs.
PLCs are robust and can survive harsh conditions including severe heat, cold, dust, and extreme moisture. Their programming language is easily understood, so they can be programmed without much difficulty. PLCs are modular so they can be plugged into various setups. Relays switching under load can cause undesired arcing between contacts. Arcing generates high temperatures that weld contacts shut and cause degradation of the contacts in the relays, resulting in device failure. Replacing relays with PLCs helps prevent overheating of contacts.
PLCs do have disadvantages. They do not perform well when handling complex data. When dealing with data that requires C++ or Visual Basic, computers are the controllers of choice. PLCs also cannot display data well, so external monitors are often required.
PLC Hardware Components
A central processing unit (CPU) serves as the brain of the PLC. It is a -16 or -32 bit microprocessor consisting of a memory chip and integrated circuits for control logic, monitoring, and communicating. The CPU directs the PLC to execute control instructions, communicate with other devices, carry out logic and arithmetic operations, and perform internal diagnostics. The CPU runs memory routines, constantly checking the PLC (PLC controller is redundant) to avoid programming errors and ensure the memory is undamaged.
2. PLCs work with inputs, outputs, a power supply, and external programming devices.

Memory provides permanent storage to the operating system for data used by the CPU. The system’s read-only memory (ROM) stores data permanently for the operating system random access memory (RAM) stores status information for input and output devices, along with values for timers, counters, and internal devices. PLCs require a programming device, either a computer or console, to upload data onto the CPU.
3. A CPU operating cycle includes the following steps: a) start scan; b) internal checks; c) scan inputs; d) execute program logic; and e) update outputs. The program repeats with the updated outputs.
PLCs read signals from different sensors and input devices. These input devices can be keyboards, switches, or sensors. Inputs can be either in digital or analog form. Robots and visual systems are intelligent devices that can send signals to PLC input modules. Output devices such as motors and solenoid valves complete the automated system.

4. The top image depicts common inputs in a PLC, including push buttons and switches. Output connections are shown in the bottom image and include signal out (SOL), pilot light (PL), and motor ignition (MI).
Sinking and sourcing are two important terms when discussing input and output connections of PLCs. Sinking is the common ground line (-) and sourcing is the common VCC line (+). VCC stands for the positive supply voltage connection point. Sinking and sourcing inputs only conduct electricity in one direction. Each input has its own return line, and several inputs connect to one return line instead of several separate return lines. These common lines are labeled “COMM.” Sensor outputs mark the size of the signal given.

Direct current (dc) input modules connect to sourcing or sinking transistor type devices. Alternating current (ac) input modules are less common than dc inputs because most sensors have transistor outputs, so if the system uses a sensor input, it will most likely be dc; ac inputs take longer for PLCs to see compared to dc inputs. A typical ac input is a mechanical switch used for slow mechanical drives.
Relays are one of the most common output connections. A relay can switch ac or dc modules because they are non-polarized. A relay is slow, switching and settling at speeds of 5 to 50 milliseconds (ms), but can switch a large current. For example, a relay can be used for a low-voltage battery to switch a 230 volt AC main circuit. Transistor connections are faster than a relay and have a long lifespan. Transistors switch a small current, but only work with dc. An example of a high-power transistor has a current of 15 amps with a max voltage of 60V. Triac output (triode for alternating current) connections only control ac loads. Like a transistor, a triac is faster and handles large ac loads. A triac output, for example, can handle voltages of 500 to 800 with a current of 12 amps.
PLC Programming Language
Five programming languages are used in PLCs. They are defined by the international standard IEC 61131. Ladder logic is one of the most commonly used PLC languages. In it, symbols represent opening and closing relays, counters, timers, shift registers, and mathematical operations. The symbols are arranged into the desired program routine. Rules in ladder logic are termed “rungs.” Each rung has a single output, but a single input can be found in more than one rung.
5. Ladder logic can be scanned by PLCs either in horizontal formats shown here (left to right starting in the upper lefthand corner and progressing to the next line) or in vertical formats (column by column starting in the upper left hand corner). | | are switches while ( ) is the action command.
Another programming language is function block diagram (FBD). It describes functions between input and output variables. The function, represented by blocks, connects input and output variables. FBD is useful in depicting algorithms and logic from interconnected controls systems.

Structured Text (ST) is a high-level language that uses sentence commands. In ST, programmers can use “if/then/else,” “SQRT,” or “repeat/until” statements to create programs.
Instruction list (IL) is a low-level language with functions and variables defined by a simple list. Program control is done by jump instructions and sub-routines with optional parameters
Sequential Function Chart (SFC) language is a method of programming complex control systems. It uses basic building blocks that run their own sub-routines. Program files are written in other programming languages. SFC divides large and complicated programming tasks into smaller and more manageable tasks.
6. Function Block Diagrams use elementary blocks to represent functions and receive inputs from lines entering from the left. Lines exiting to the right represent output results.

PLC Communications
RS-232 is the most common method PLCs use to communicate with external devices. It is a serial communication standard that uses binary code to transmit data in American Standard Code of Information Interchange (ASCII) format. ASCII translates letters and numbers into binary code that computers can read. ASCII is a 7-bit code (a bit being “1” or “0”) that, when translated, results in 128 characters. PLC serial ports transmit and receive data as voltages. PLCs can be either data terminal equipment (DTE) or data communications equipment (DCE). A DTE, for example, can be a computer, while a modem is a DCE. Typically, PLCs are DTEs and external devices are DCEs. When the PLC and the external device connected to it are the same equipment (i.e., DTE/DTE or DCE/DCE), they cannot communicate with each other and a null-modem connection must be used.

In serial communications, data gets transmitted one bit at time. Data is separated into its constituent bits for transmission and reassembled when received by an external device. A “start bit” is the initial signal sent and precedes any other communication bits. It is considered the “space” or negative voltage. The “stop bit,” the last code sent, is considered a “Mark” or a positive voltage.
Eight bits make a byte and PLCs are byte-oriented. ASCII is a seven-bit code, so the eighth (or “parity byte”) checks to see if data has been corrupted. Common forms of parity include even (1), or odd (0). The total number of 1s in the byte adds up to an even or odd number. The sending equipment determines if the communication is even or odd and receiving equipment compares the result of the parity to the eighth bit to ensure they match. If a device transmits 1001101 and computes it to be an odd value, it will add a 1 to the eighth bit and send 10011011. The receiver decides the bit is odd and verifies an odd total of 1 characters.
Baud rate is the number of bits per second transmitted from DTE to DCE. An RS232 transmission would appear as baud rate, data bits, and parity-stop bits. For example, the string 9600-8-1-1 translates to a 9600 baud rate, 8 data bits, a 1 for parity, and a 1 stop bit to end the transmission.
Software handshaking ensures devices are ready to send and receive data. The receiver sends the XOFF character when it wants the transmitter to pause sending data. It sends the XON character when it is ready to receive data again. XOFF is sometimes referred to as the hold-off character and XON as the release character.
A delimiter is added to the end of messages to tell receivers to process the data just received. The most common delimiter is the “carriage return” (CR). The PLC or external device receives the delimiter and takes data from its buffer. The buffer temporarily stores data before it is processed. The line feed (LF) is sometimes sent with the CR character. If viewed on a computer, the page moves down a line to start a new line of communication.
PLC Selection Criteria
7. Selecting the correct PLC will depend on the needs and size of the automation system. Above are examples of different PLCs with varying inputs, outputs, and display options.

There are several requirements to keep in mind when choosing PLCs. Is the proposed system new or an existing one? Either way, ensure the controller works with mating hardware.
Environmental conditions will affect PLC performance. Typical controllers operate in temperatures from 0 to 55°C (32°-130°F). The number of discrete devices (On/Off logic devices) and analog devices determines the number of I/O connections the PLC will need. If the discrete devices are ac or dc, determine if the PLC can support the required signal.
Determining CPU requirements is important for calculating the amount of RAM needed for data manipulation and storage. Counters and timers use RAM to store set points, current values, and other internal flags. If data must be stored over a long period of time, CPU memory must be sized appropriately.
Program memory or ROM stores program instructions. Analog devices usually require 25 words of memory per device. Examples of analog devices are voltage, current, and temperature meters or sensors. Simple and sequential applications typically require five words of memory per I/O device. Complex applications are not as predictable and need more program memory space.
Serial and Ethernet connection-based I/O hardware are typical choices for remote connections. Remote devices are needed when the PLC is located separately. Serial connections have a max distance of 50 feet while Ethernet connections can go to a max of 328 feet. These remote devices are referred to as distributed I/O. Finally, be sure the PLC understands program instructions. Some PLCs come with proportional integral derivative functions that eliminate the need for technicians to write specific code for closed-loop process control. 

Sources:- http://machinedesign.com/engineering-essentials/engineering-essentials-what-programmable-logic-controller

Wednesday, June 17, 2015

New SIMATIC S7-1200 CPUs With Upgraded Firmware Recommended for New Designs

 RS Components (RS), the trading brand ofElectrocomponents plc (LSE: ECM), the global distributor for engineers, is now shipping the latest in the popular Siemens SIMATIC S7-1200 CPU series, featuring upgraded firmware V4.1 that introduces performance improvements, extra features, and support for forthcoming failsafe CPUs.

The new firmware has improved instruction processing for faster execution of PLC programs, while increased work memory makes extra resources available for program and user data.
New features include enhanced motion capabilities such as position control and support for analogue or PROFIdrive drives. A PID control block allows temperature control in active heating or cooling systems, as well as interval measurements using high-speed counters. In addition, a built-in station web server allows flexible access via IP address. There is also dynamic copy protection, support for shared I-Device allowing connection of multiple controllers and fast data exchange, and enhanced configuration handling that allows modules to be specified and left unconnected without triggering alarms.
The firmware also introduces support for the forthcoming failsafe S7-1200 CPUs and signal modules (SM) for implementing safety-related appliances.
The latest S7-1200 FW4.1 CPUs, available now at RS Components, are recommended for new designs. 13 part numbers offer versatile configurations of analogue and 24V digital inputs and outputs. Version 4.1 firmware is also available to download for existing S7-1200 CPUs.

Monday, June 15, 2015

PLC Programmer / Automation Engineer

The Role 
The successful applicant will work on all kinds of automated machinery, including Filter Controls, Conveyor systems and lift applications. You will be required to create programmable logic controller (PLC) programs from customers FDS to realise such systems. You will contribute to panel designs, component layouts and panel assembly, loading programs and troubleshooting wiring and circuits. You will be required to commission panels (and troubleshoot problems) on customer sites from time to time, requiring occasional travel and overnight stays worldwide.
The Company
 We are a well-established company within the Automation Industry, offering bespoke control solutions for a range of clients.
 The Candidate 
The successful applicant will be a qualified engineer with PLC programming and hands-on electrical panel production experience. You will be able to read and modify Electrical CAD drawings. Recent experience of panel programming, design and project management is desired. 
Experience of variable speed drives, digital and analogue inputs / outputs and a willingness to learn new applications is required. Various PLC Manufacturers will be used in our applications. 

You will be fully IT competent, have a full UK driving licence with excellent attention to detail, time management and customer relationships, taking pride in your personal and company performance. 

If you wish to be considered for the role of PLC programmer / Automation Engineer, please forward a CV in MS Word format, in confidence, stating current remuneration details and availability.

Source:- http://jobs.lincolnshireecho.co.uk/job/501529738/-plc-programmer-automation-engineer/

GATE Exam 2020 | Syllabus, Eligibility, Application Form, Exam and Result

GATE Exam 2020 | Syllabus, Eligibility, Application Form, Exam and Result