Actuator Sensor-Interface: Intelligent Cabling for a Machine
Automation involves exchange of data from across the field to a central control unit. In the conventional system, the entire machine is surrounded by cables which increase the hassles and time involved in maintenance, commissioning and diagnostics. Field bus technology involves the use of a common protocol for data exchange in a serial way between the central control unit and the field devices thereby eliminating the need of traditional hardwiring. Decentralized I/O modules are kept on the field and the sensors and actuators are wired to these. These remote I/O modules communicate to the PLC by bus-systems or communication protocols like PROFIBUS/ MODBUS/ AS-i etc.In the yester years, there was no scarcity of materials like copper, iron etc. Supplies of the materials were more than the demand. Labour was also available in abundance. However, over the years, the labour cost and the material cost has been increasing which in turn means an increase in the production cost or the product cost. Additionally there is an ever-increasing pressure to reduce the prices of the products due to the increasing competition. Hence the manufacturers are on a constant look-out for reducing the cost of production and thereby to reduce the price of their products. Automation is one of the ways to achieve this.Centralized SystemThe introduction of automation was a revolution in itself. Automation involves exchange of data from across the field to a central control unit. The data exchanged can be of various types ranging from system data, process parameters, analogue data or binary data. Also the nature of exchange of these data varies and can be cyclic or acyclic. Taking an example of a conventionally wired conveyor system:Along the conveyor line, there are sensors like limit switches, proximity sensors etc. which give input to the PLC about the materials being conveyed. Based on the requirement, the PLC gives output to the contactors to switch off or switch on the conveyor. The switching action can also be done locally by means of actuators like push buttons, E-stop button etc. Conventionally, each of the actuator/ sensor along the conveyor was connected by hard-wire to the marshalling tier. From the marshalling tier, the inputs and outputs are connected to the PLC by means of a multi-core cable. This was referred to as "centralized control" where in all the data from the entire plant would be wired to the PLC located at certain location in the plant. The following drawbacks were encountered:These drawbacks lead to the development of the decentralized control systems – which means distributing intelligence in the field. To make communication faster and the automation hardware simpler, field bus concepts came into existence. Field bus technology involves the use of a common protocol for data exchange in a serial way between the central control unit and the field devices thereby eliminating the need of traditional hardwiring. In this system, only the hardware or the hardware as well as the software can be decentralized. Decentralized I/O modules are kept on the field and the sensors and actuators are wired to these. These remote I/O modules communicate to the PLC by bus-systems or communication protocols like PROFIBUS/ MODBUS/ AS-i etc.Decentralized System (System using AS-i)
Actuator sensor interface is a bus system designed as an interface (connection media) for all simple binary ON/ OFF field devices (pushbuttons, limit switches, proximity sensors, valves, contactor coils) to the higher level of automation. In this communication bus system or protocol, the hardware is only decentralized. In this system, the basic components at the field level are AS-i master, AS-i slaves (or I/O modules) and the AS-i power supply. AS-i, slave modules (I/O Module selected based on the number and type of inputs and outputs) are mounted near the sensor cluster. A single AS-i cable runs through the slaves, to the AS-i master and power supply. The AS-i master in turn is connected to the PLC. Thus, AS-I replaces the cable tree at the lowest level of automation in the industry where conventional hardwiring/ field bus tend to be too complicated, too slow or too expensive. The result is an immense reduction in wiring – "one instead of a thousand cables".What is AS-i??AS-i is an open and manufacturer-independent bus system transmitting process- and machine-level digital/ analog signals and safety-oriented signals to the PLC. It’s a universal interface between actuators and sensors on the field level to the superior control level of PROFIBUS/ Ethernet/ others. AS-I is basically a Master-Slave system. Master-Slave refers to the method the field-bus uses to transfer information. The master is responsible for the operations of the bus system. One AS-I master can have a maximum of 62 slaves of 4I/4O each (according to AS-I specification ver 3.0) over a length of 100m (expandable upto 600 m with repeaters and other accessories).AS-interface was conceived as a single master system with cyclic polling. This means that there is only one control module (master) in the AS-Interface network which polls the data of the other nodes (slaves) at precisely defined intervals. Up to four useable input bits and four useable output bits are exchanged between a slave and the master in any one cycle. AS-interface has been optimised for volumes of data that correspond precisely to the requirements of the lowest field levelThe basic components in an AS-i system consist of master, slaves, power supply and the AS-i cable.AS-i Master – It provides an interface between the slaves and the PLC. The AS-Interface master forms the connection to higher level controls. It independently organizes the data traffic on the AS-Interface line and is responsible for parameter settings, monitoring and diagnostic functions.AS-i Slaves – The AS-i slaves can either be AS-i enabled valves, push button stations, limit switches etc or can be AS-i enabled I/O cards on which the actuators and sensors are connected.AS-Interface slaves include the AS-i electronics. The I/O cards can either be IP20 (can be installed in a control cabinet) or IP67 modules (that are directly used in the field).AS-i Power Supply – This is a special 30V DC power supply which decouples the power and the data signal. The power supply units generate a controlled DC voltage of 24 or 30 V with a high degree of stability and low residual ripple. They supply the network’s electronics, i.e. the AS-i modules and the master as well as the connected sensors. AS-Interface power supply units generate a nominal voltage of 30 V DC.AS-i cable – The AS-i cable has to meet the specifications laid down in the AS-i standard specifications. The yellow, flat cable is characteristic for the AS-Interface. Data and power for the sensors are transferred along this cable. A second, black flat cable is used to supply the actuators with 24 V. Both of these cables use the piercing technology, specifically developed for AS-i. This allows every node to be simply snapped onto the two profiled cables at any location – also with the correct polarity. In case of the IP67 AS-i slaves, the wiring is done by "piercing technology". In this case, the geometry of the cable is such that polarity reversal is not possible and hence errors during installation are minimized. The trapezoidal profile with the profiled lug ensures a high degree of protection against polarity reversal (mechanical code). In case of IP20 modules, regular copper wires can be used. The IP20 modules have removable terminals which makes the wiring easy.Benefits of AS-i"One instead of a thousand cables"In the conventional system, the entire machine is surrounded by cables which increase the hassles in maintenance. By AS-i, maintenance is hassle-free.
- Less wiring implies less cost – cabling, wiring, maintenance etc.
- No wiring faults. Confusion of terminals excluded.
Short downtimes thanks to fast replacementThe IP67 modules enable quick installation. The slaves in an AS-i network hooks on to the cable without any trouble due to the piercing technology of the cables. Hot-replacement, ie., replacement of the modules without shutting down of the system is possible. Contact needles pierce through the cable insulation and make secure contact with the copper conductor. When the needles are pulled out again to remove a slave, the cable’s self-healing capability ensures that the holes close automatically, providing full insulation again (in the case of EPDM cables)Less commissioning and configuration timeThe slaves can be pre-addressed using the addressing tool. The master can be parameterized easily without putting it on-line.Less maintenance timeIn case of any failure, the diagnostics are fast. The replacements of the salves are easy due to the hot-replacement featureEasier diagnosticsDue to diagnostics available at various levels the down-time of the plant reduces. AS-i provides diagnostic information at the device level by means of LEDs. Diagnostic information are also available on the AS-i Master. It can also be configured to get diagnostic information on PLC/ SCADA/ HMI panels.ExpandabilityThe system is flexible and hence is expandable very easily with minimal downtime. A shut-down of the plant is not required for a long time due to the off-line configurability, hot-replacement etc.AS-i – as part of Totally Integrated AutomationThe AS-i association was founded in 1991 and since then, the specifications for AS-i has undergone continuous improvement. Presently, AS-i adheres to specification version 3.0.Some of the features of AS-i specification ver 3.0 are:
- Binary I/O nodes supporting A/B addressing with 4 Inputs and 4 Outputs
- Binary I/O nodes supporting A/B addressing with 8 Inputs and 8 Outputs
- Integrated safety (AS-i safe)
- Improved diagnostics
All AS-Interface products correspond to
- Euro Norm EN 50295 and
- World Standard IEC 62026-2
All certified AS-i products (recognisable by the AS-interface shadow logo and the corresponding test number) are fully compatible with each other independent of the manufacturer and are interchangeable.AS-i forms part of the TIA pyramid (Totally Integrated Automation – the hierarchy of the communication protocols available.) AS-i is at the lowest control level, where it is used to interlink process-related devices like sensors, actuators etc, with one-another and to the next higher automation level.The next level is either the field-bus level like Profibus/ Modbus etc followed by the operating control level like Industrial Ethernet.Being the lowest level of automation, AS-i is not designed to handle large volumes of data. The structure and length of the data frame is fixed. Up to four useable input bits and four useable output bits are exchanged between a slave and the master in any one cycle. At this level, however, there are a high number of connected devices all with the requirement for real time/deterministic capability.From AS-i, gateways to EtherNet/IPTM, PROFINET, Modbus/TCP and others are available. With the new and continuously improving capabilities, AS-interface is the ideal partner network for any of the currently available Ethernet based industrial protocols. The future of the communication networks are seen as a 2-level hierarchy comprising of Field bus like AS-i and then the Ethernet based protocols.The author is Mangala R. Nair, Control Products Department, Siemens Ltd
Indian cement industry is well known for its energy and natural resource efficiency
Dr Hitesh Sukhwal, Deputy General Manager – Environment, Udaipur Cement Works Limited (UCWL) takes us through the multifaceted efforts that the company has undertaken to keep emissions in check with the use of alternative sources of energy and carbon capture technology.
Tell us about the policies of your organisation for the betterment of the environment.
Caring for people is one of the core values of our JK Lakshmi Cement Limited. We strongly believe that we all together can make a difference. In all our units, we have taken measures to reduce carbon footprint, emissions and minimise the use of natural resources. Climate change and sustainable development are major global concerns. As a responsible corporate, we are committed with and doing consistent effort small or big to preserve and enrich the environment in and around our area of operations.
As far as environmental policies are concerned, we are committed to comply with all applicable laws, standards and regulations of regulatory bodies pertaining to the environment. We are consistently making efforts to integrate the environmental concerns into the mainstream of the operations. We are giving thrust upon natural resource conservation like limestone, gypsum, water and energy. We are utilising different kinds of alternative fuels and raw materials. Awareness among the employees and local people on environmental concerns is an integral part of our company. We are adopting best environmental practices aligned with sustainable development goals.
Udaipur Cement Works Limited is a subsidiary of the JK Lakshmi Cement Limited. Since its inception, the company is committed towards boosting sustainability through adopting the latest art of technology designs, resource efficient equipment and various in-house innovations. We are giving thrust upon renewable and clean energy sources for our cement manufacturing. Solar Power and Waste Heat Recovery based power are our key ingredients for total power mix.
What impact does cement production have on the environment? Elaborate the major areas affected.
The major environmental concern areas during cement production are air emissions through point and nonpoint sources due to plant operation and emissions from mining operation, from material transport, carbon emissions through process, transit, noise pollution, vibration during mining, natural resource depletion, loss of biodiversity and change in landscape.
India is the second largest cement producer in the world. The Indian cement industry is well known for its energy and natural resource efficiency worldwide. The Indian cement industry is a frontrunner for implementing significant technology measures to ensure a greener future.
The cement industry is an energy intensive and significant contributor to climate change. Cement production contributes greenhouse gases directly and indirectly into the atmosphere through calcination and use of fossil fuels in an energy form. The industry believes in a circular economy by utilising alternative fuels for making cement. Cement companies are focusing on major areas of energy efficiency by adoption of technology measures, clinker substitution by alternative raw material for cement making, alternative fuels and green and clean energy resources. These all efforts are being done towards environment protection and sustainable future.
Nowadays, almost all cement units have a dry manufacturing process for cement production, only a few exceptions where wet manufacturing processes are in operation. In the dry manufacturing process, water is used only for the purpose of machinery cooling, which is recirculated in a closed loop, thus, no polluted water is generated during the dry manufacturing process.
We should also accept the fact that modern life is impossible without cement. However, through state-of-the-art technology and innovations, it is possible to mitigate all kinds of pollution without harm to the environment and human beings.
Tell us about the impact blended cement creates on the environment and emission rate.
Our country started cement production in 1914. However, it was introduced in the year 1904 at a small scale, earlier. Initially, the manufacturing of cement was only for Ordinary Portland Cement (OPC). In the 1980s, the production of blended cement was introduced by replacing fly ash and blast furnace slag. The production of blended cement increased in the growth period and crossed the 50 per cent in the year 2004.
The manufacturing of blended cement results in substantial savings in the thermal and electrical energy consumption as well as saving of natural resources. The overall consumption of raw materials, fossil fuel such as coal, efficient burning and state-of-the-art technology in cement plants have resulted in the gradual reduction of emission of carbon dioxide (CO2). Later, the production of blended cement was increased in manifolds.
If we think about the growth of blended cement in the past few decades, we can understand how much quantity of , (fly ash and slag) consumed and saved natural resources like limestone and fossil fuel, which were anyhow disposed of and harmed the environment. This is the reason it is called green cement. Reduction in the clinker to cement ratio has the second highest emission reduction potential i.e., 37 per cent. The low carbon roadmap for cement industries can be achieved from blended cement. Portland Pozzolana Cement (PPC), Portland Slag Cement (PSC) and Composite Cement are already approved by the National Agency BIS.
As far as kilogram CO2 per ton of cement emission concerns, Portland Slag Cement (PSC) has a larger potential, other than PPC, Composite Cement etc. for carbon emission reduction. BIS approved 60 per cent slag and 35 per cent clinker in composition of PSC. Thus, clinker per centage is quite less in PSC composition compared to other blended cement. The manufacturing of blended cement directly reduces thermal and process emissions, which contribute high in overall emissions from the cement industry, and this cannot be addressed through adoption of energy efficiency measures.
In the coming times, the cement industry must relook for other blended cement options to achieve a low carbon emissions road map. In near future, availability of fly ash and slag in terms of quality and quantity will be reduced due to various government schemes for low carbon initiatives viz. enhance renewable energy sources, waste to energy plants etc.
Further, it is required to increase awareness among consumers, like individual home builders or large infrastructure projects, to adopt greener alternatives viz. PPC and PSC for more sustainable
What are the decarbonising efforts taken by your organisation?
India is the world’s second largest cement producer. Rapid growth of big infrastructure, low-cost housing (Pradhan Mantri Awas Yojna), smart cities project and urbanisation will create cement demand in future. Being an energy intensive industry, we are also focusing upon alternative and renewable energy sources for long-term sustainable business growth for cement production.
Presently, our focus is to improve efficiency of zero carbon electricity generation technology such as waste heat recovery power through process optimisation and by adopting technological innovations in WHR power systems. We are also increasing our capacity for WHR based power and solar power in the near future. Right now, we are sourcing about 50 per cent of our power requirement from clean and renewable energy sources i.e., zero carbon electricity generation technology. Usage of alternative fuel during co-processing in the cement manufacturing process is a viable and sustainable option. In our unit, we are utilising alternative raw material and fuel for reducing carbon emissions. We are also looking forward to green logistics for our product transport in nearby areas.
By reducing clinker – cement ratio, increasing production of PPC and PSC cement, utilisation of alternative raw materials like synthetic gypsum/chemical gypsum, Jarosite generated from other process industries, we can reduce carbon emissions from cement manufacturing process. Further, we are looking forward to generating onsite fossil free electricity generation facilities by increasing the capacity of WHR based power and ground mounted solar energy plants.
We can say energy is the prime requirement of the cement industry and renewable energy is one of the major sources, which provides an opportunity to make a clean, safe and infinite source of power which is affordable for the cement industry.
What are the current programmes run by your organisation for re-building the environment and reducing pollution?
We are working in different ways for environmental aspects. As I said, we strongly believe that we all together can make a difference. We focus on every environmental aspect directly / indirectly related to our operation and surroundings.
If we talk about air pollution in operation, every section of the operational unit is well equipped with state-of-the-art technology-based air pollution control equipment (BagHouse and ESP) to mitigate the dust pollution beyond the compliance standard. We use high class standard PTFE glass fibre filter bags in our bag houses. UCWL has installed the DeNOx system (SNCR) for abatement of NOx pollution within norms. The company has installed a 6 MW capacity Waste Heat Recovery based power plant that utilises waste heat of kiln i.e., green and clean energy source. Also, installed a 14.6 MW capacity solar power system in the form of a renewable energy source.
All material transfer points are equipped with a dust extraction system. Material is stored under a covered shed to avoid secondary fugitive dust emission sources. Finished product is stored in silos. Water spraying system are mounted with material handling point. Road vacuum sweeping machine deployed for housekeeping of paved area.
In mining, have deployed wet drill machine for drilling bore holes. Controlled blasting is carried out with optimum charge using Air Decking Technique with wooden spacers and non-electric detonator (NONEL) for control of noise, fly rock, vibration, and dust emission. No secondary blasting is being done. The boulders are broken by hydraulic rock breaker. Moreover, instead of road transport, we installed Overland Belt Conveying system for crushed limestone transport from mine lease area to cement plant. Thus omit an insignificant amount of greenhouse gas emissions due to material transport, which is otherwise emitted from combustion of fossil fuel in the transport system. All point emission sources (stacks) are well equipped with online continuous emission monitoring system (OCEMS) for measuring parameters like PM, SO2 and NOx for 24×7. OCEMS data are interfaced with SPCB and CPCB servers.
The company has done considerable work upon water conservation and certified at 2.76 times water positive. We installed a digital water flow metre for each abstraction point and digital ground water level recorder for measuring ground water level 24×7. All digital metres and level recorders are monitored by an in-house designed IoT based dashboard. Through this live dashboard, we can assess the impact of rainwater harvesting (RWH) and ground water monitoring.
All points of domestic sewage are well connected with Sewage Treatment Plant (STP) and treated water is being utilised in industrial cooling purposes, green belt development and in dust suppression. Effluent Treatment Plant (ETP) installed for mine’s workshop. Treated water is reused in washing activity. The unit maintains Zero Liquid Discharge (ZLD).
Our unit has done extensive plantations of native and pollution tolerant species in industrial premises and mine lease areas. Moreover, we are not confined to our industrial boundary for plantation. We organised seedling distribution camps in our surrounding areas. We involve our stakeholders, too, for our plantation drive. UCWL has also extended its services under Corporate Social Responsibility for betterment of the environment in its surrounding. We conduct awareness programs for employees and stakeholders. We have banned Single Use Plastic (SUP) in our premises. In our industrial township, we have implemented a solid waste management system for our all households, guest house and bachelor hostel. A complete process of segregated waste (dry and wet) door to door collection systems is well established.
Tell us about the efforts taken by your organisation to better the environment in and around the manufacturing unit.
UCWL has invested capital in various environmental management and protection projects like installed DeNOx (SNCR) system, strengthening green belt development in and out of industrial premises, installed high class pollution control equipment, ground-mounted solar power plant etc.
The company has taken up various energy conservation projects like, installed VFD to reduce power consumption, improve efficiency of WHR power generation by installing additional economiser tubes and AI-based process optimisation systems. Further, we are going to increase WHR power generation capacity under our upcoming expansion project. UCWL promotes rainwater harvesting for augmentation of the ground water resource. Various scientifically based WHR structures are installed in plant premises and mine lease areas. About 80 per cent of present water requirement is being fulfilled by harvested rainwater sourced from Mine’s Pit. We are also looking forward towards green transport (CNG/LNG based), which will drastically reduce carbon footprint.
We are proud to say that JK Lakshmi Cement Limited has a strong leadership and vision for developing an eco-conscious and sustainable role model of our cement business. The company was a pioneer among cement industries of India, which had installed the DeNOx (SNCR) system in its cement plant.
NTPC selects Carbon Clean and Green Power for carbon capture facility
Carbon Clean and Green Power International Pvt. Ltd has been chosen by NTPC Energy Technology Research Alliance (NETRA) to establish the carbon capture facility at NTPC Vindhyachal. This facility, which will use a modified tertiary amine to absorb CO2 from the power plant’s flue gas, is intended to capture 20 tonnes of CO2) per day. A catalytic hydrogenation method will eventually be used to mix the CO2 with hydrogen to create 10 tonnes of methanol each day. For NTPC, capturing CO2 from coal-fired power plant flue gas and turning it into methanol is a key area that has the potential to open up new business prospects and revenue streams.
Sustainable Mining for the Future
ICR presents a case for responsible reporting across the mining supply chain.
The importance of mining, in times of sustainability reporting, is rising in stature. The rise of mining output is not waning but growing and the share of construction mineral ore in all of this still remains close to 50% of the entire extractive output.
It is estimated that the global combined extractive output in mining is going to grow to 167gt in 2060, from the 2019 statistics of 92 gt. Out of this 27% is biomass, 15% is fossil fuel, 9% is metal ores and the balance is non-metallic minerals, bulk of which goes to the construction industry. While sustainability considerations would be driving most of the future growth, most notably, metals will be needed for electric storage batteries (eg. for electric cars), which require aluminium, cobalt, iron, lead, lithium, manganese and nickel but also for other relevant technologies, including those used for the production of wind turbines and solar panels; far greater amounts of metals are needed for clean energy production than the traditional energy production from fossil fuels. Thus the growth in metals for sustainability will offset the drop in extraction that would stem from growth in recycling.
An overview of the mining sector
Mining for non-metallic minerals, from where the construction industry sources all its inputs, perhaps falls under the ASM (artisanal and small-scale mining), which has still remained labour intensive and suffers from safety issues all across, the developed world and developing, all have the similar challenges to grapple with. Efforts to increase automation, mechanisation and digitisation also come with the fair share of demands from the local community, which can hardly be neglected. While Large Scale Mining (LSM) is moving towards mechanisation and automation with minimum labour resources, the focus is increasingly shifting towards partnerships on supply chains that connect local procurement partners and the community at large to the external markets.
One of the significant developments has been the shift towards battery-electrification of mobile equipment in the mines to the complete automation of all mining equipment with Net zero targets in focus. There are man-less mines in existence already where underground operations are being orchestrated through battery-electric equipment remotely connected through control systems. The partnerships between mining companies and the mining equipment OEMs is ensuring a smooth transition in this area that will take the use of fossil fuels in mines to a negligible proportion (mostly as consumables) in the near future. This however calls for a skills inventory crossover, that would need larger hand holding with the local government and other institutions as well as the local communities.
Sustainability in mining
The goals of sustainable development in mining would include transparency as a key theme between a large pool of actors that constitute and connect the upstream to the downstream supply chain partners (supplier, trader, smelter refiner, component producer, contract manufacturer, end user, intermediaries, agents and transporters). This would also entail collaboration with governments and across the supply chain to support a circular economy to minimise inputs to waste from the mining process and to increase the reuse, recycling and repurposing of raw materials and products to improve sustainable consumption. The traceability systems also ensure that the level of information that is shared and disclosed along the value chain. They illustrate the chain of custody, which is the sequence of stages and custodians the product is transferred to through the supply chain.
The transparency of reporting across the entire supply chain is at the core of this and this has two parts:
- Minimise resource use and waste (use of water, energy, land and chemicals and minimise production of effluent, waste and chemicals) and also purpose waste rock
- Incorporate life cycle thinking (extend responsible sourcing to all suppliers and collaborate to connect the consumer with sustainable raw materials).
India-centric big picture
India as a country has progressed well in SDG Reporting and Sustainable Development in the mining sector that accounts for 2.5% of the country’s GDP. Many of the key companies of the sector are SOEs. India is abundant in natural mineral resources and the country is one of the world’s main producers of iron ore and bauxite. India is the third largest producer of coal, behind the US and China. In construction related extractive minerals, India is the world’s second largest producer. Section 135 of India’s Companies Act on CSR and Regulation for large public companies to produce Business Responsibility Reports, makes it imperative for Large Mining companies (both metallic and non-metallic extractive ones) to be part of the SDG reporting, that cover diverse range of sustainability areas including GHG gas emissions, energy use, stakeholder engagement and labour and human rights.
In 2011, the Indian Ministry of Corporate Affairs issued the National Voluntary Guidelines on the Social, Environmental and Economic Responsibilities of Business (NVGs). Building on the NVGs, a new guidance entitled the National Guidelines on Responsible Business Conduct (NGRBC) was released in 2018. The new guidance integrates the ‘Respect’ pillar of the United Nations Guiding Principles and the UN Sustainable Development Goals.
Following other countries, India is also on the path of developing sustainability guidelines for the end-to-end supply chains in the mining sector. This will only ensure stakeholder participation for safety and sustainability in all four stages: profiling, reservation, exploration and departure. For future growth in mining, that will entail coal, iron-ore, bauxite and limestone extraction as the top four mining categories, it is an absolute necessity that focus on SDG reporting is carried through beyond the voluntary reporting mandate to encompass the aspirations of the communities and investors who would be the major beneficiaries of such initiatives. Without their blessings, the growth in these sectors would be mired by distrust and lack of transparency, which remains to be one of the dampeners for sustainable growth in mining.