Sample Report On Part1

Section 1

Introduction
It is a part of the job of an energy manager that he minimizes the energy loss of the building by controlling the ambient temperature of the building or different parts of the building. In order to maintain the temperature and save valuable energy, a data acquisition and monitoring system is needed that will display the ambient temperature with the help of sensors. This supervisory control system will be designed to control the remote infrastructure that handles the heating system. The energy manager will be in control of this system. First the data of the room will be measured by an analog sensor that in the form of physical disturbance, then an analog to digital converter will be used to convert the data acquired into digital signals. A PLC connected with an OPC will be used here.

Connecting PLC to OPC

The first step would be the conversion of the physical quantity (i.e. Temperature) to an analog signal like voltage or current. After this the signal undergoes analog to digital conversion. The intensity of the current and/or voltage is equated to a numerical value based on comparison. We use an ADC for this purpose (Analog to Digital Converter). We then assign the digitized voltage/current value to a variable. Now the Value of ready to be used in a PLC logic or code. Our controller is further programmed to perform communication tasks by connecting to other controllers and PCs.
“A PLC or a Programmable control unit is an industrial computer control system that continuously monitors the state of input devices and makes decisions based upon a custom program to control the state of output devices.
Almost any production line, or for that matters sake any process can be enhanced if this type of control system is used. The foremost benefit however in using a PLC is the ability to change and replicate the operation or process while collecting and communicating important information.” (Amci.com, 2014)
“OPC is a software interface standard that allows Windows programs to communicate with industrial hardware devices. OPC is implemented in server or client pairs. The hardware communication protocol used by a PLC is converted by the OPC server that basically is a software program aimed at doing this job. Into the OPC protocol. The OPC client software is any program that needs to connect to hardware, just like an HMI the OPC client which uses the OPC server to get data from or send commands to the hardware.” (Opcdatahub.com, n.d.)
Communication protocols such as RS232, RS486 or MODBUS will be used to communicate with other devices. The OPC server program uses the communications network and requests data from all the devices connected in the network. The OPC tag is programmed to search for a particular memory location of a particular device (PLC) and describe its function and property (i.e. Oil temperature) by putting a label on it. The PLC then reads the OPC tags and then terms they ready to be communicated to other devices.

Section 2

Databases
A database is a record comprising of atomic data types. These are stored in Computer. The data is organised in tables and then these tables are linked thus resulting in the structure. There is a system known as the (DBMS) that manages the database. Two types of data bases have been discussed.1) relational database 2) object database. Database normalisation minimizes duplication of information and therefore it safeguards the database against data anomalies. For or purpose we will discuss two databases.

Relational databases.

“A relational database allows you to easily find specific. It also allows you to sort based on any field and generate reports that contain only certain fields from every record. Tables are used by Relational databases to store information. The standard fields and records are represented as columns (fields) and rows (records) in a table. With a relational database, you can quickly compare information because of the arrangement of data in columns. The database takes advantage of this uniformity to build completely new tables out of required information from tables that already exist. Putting it simply it uses relationship of similar data to increase the speed and versatility of the database.”(howstuffworks.com, 2001)
Database normalisation is a step taken in order to prevent the unnecessary duplication of information in a database. By achieving database normalization, unnecessary data duplication is avoided and some structural or logical problems are also avoided on the go like data anomalies. Consider the table in Figure 5.9 where the same name appears for different lines.

There are a number of rules to divide up the data and make it relational.

Object databases.
“Object oriented databases are also called Object Database Management Systems (ODBMS). Object databases store objects rather than data like real numbers, strings or integers. Objects are used in object oriented languages such as, C++, small talk, java and others. Objects basically consist of the following:
Attributes - Attributes are data which defines the characteristics of a particular object. This data can be simple like real numbers integers and strings or it may be a reference to a complex object.
Methods - Methods define the behaviour of an object and are what was formally called procedures or functions.”(Comptechdoc.org, 2014)
The CSV or comma separated variable is a method of storing data tabular form. They are common on all computers and are used to import and export data from different software.
CSV is one of the implementation of the delimited text file, which uses a comma to separate values. But it is different from other file formats because of using a double quote character around fields containing reserved characters. Because only one table exists and is store in a CSV fie it is referred to as flat file. It is read or written sequentially and doesn’t have indexes that can be separate from individual records. Each record has field instances like title first name surname address. Each field instance can have a data value that can be numeric or text or alphanumeric etc.
Two types of flat files are 1) either those that have a variable length record 2)fixed length record.IN variable length record the file is read sequentially with fixed ones the file is accessed randomly. In some softwares the user can set the delimiter value. Databases using flat files aren’t fast as we would have liked but they still have their uses over some of the faster approaches. This is particularly evident in the case of simple systems that need a quick database. The dearth of connected fields helps us minimizing errors due to missing fields and many databases use this format, especially the downloadable ones.

Data Types

“A data type is a data classification, which has the ability to store specific types of data. Data types are primarily used in programming, whereby to store data variables are created. Every variable is assigned to a data type which determines what type of data the variable may contain.
The term "data type" and "primitive data type" are often used in place of each other. Primitive data types are supported by programming language. E.g. Integer, string, and character are all the primitive data types. These data types can be used by programmers when creating variables in programs. For example, a variable may be created called "last name" and define it as a string data type. The variable will then store data as a string of characters.” (Christensson, 2009).
“Non-primitive data types are not defined by the programming language, but are instead created by the programmer. They are sometimes called "reference variables," or "object references," since they reference a memory space, in which data is stored. In JAVA, data types that are non-primitive are called "objects" reason being they are not predefined, rather created. While an object may contain any data type, the information that the object references may still be stored as a primitive data type.” (Christensson, 2009).
Different combination of primitive data types are used in the data types and due to this combination, they are fundamentally different from other data types. They can be seen as an organization of specific component data types with a specific functionalism. E.g. software objects, comma delimited files, XML files, schemas, files of recorded values stored in relation to time (EEG), images, sounds etc.”
“Atomic data are data elements that represent the lowest detail level. E.g. updated room temperatures every second would be atomic data, on the other hand rollups such as summary and invoice totals from invoices are aggregate data. In the field of computer science specifically in programming, atomic data are a data type whether it is an action or an object that can no longer be broken down into smaller units. In other terms, the data type can no longer be divided, or be changed and whole.”(Team, 2007).

Microsoft Access

Microsoft Access can be used to manage the databases required for this whole operation. The software can be used to make an application and its user friendly interface that can be used to manage the databases. It is up to the programmer to use the variables but both the primitive and non-primitive need to be found and put into proper usage.

Section 3

Communication
Different types of communication of PLC take place. We should concern ourselves with 3 categories of this communication that is used in industrial control. First is serial communications next is industrial communications network and the last is industrial input output networks.
The simplest type of this communication is direct, one way, connection between the two devices in which data is being transmitted one bit at a time.   This is called Serial Communications. When a programming software, that’s on a PC, is connected directly to PLC through a RS-232 port – serial communication takes place.
Industrial networks mainly cover production control therefore it’s essential that high reliability and high power are ensured. Industrial networks also enable a connection with the centralized operator layer (PC with the function SCADA/MES) of the whole company information system and top company ERP system. Industrial networks in common corporations only use 3 layers from the standard reference communication model-link, application and physical. Identical communication protocol is used so that the PLC knows how to communicate in a network. The selection of the protocol is dependent on which network is selected. Basically in a way it summarises the rules that govern communication and its parameters. In some of the situations different quantity of PLCs can be linked together to a master PLC unit therefore making it possible to send and receive data from the other units. (Plcmanual.com, n.d.)
Parallel standardsIEEE-488 is the standard interface that is commonly used for parallel communication. Which is termed as GPIB (general purpose instrument Bus). Parallel data communications between talker’s controllers and listeners can take place. There are a total 24 lines 8 are ground lines 3 are handshaking 8are for data and 5 are for status and control (Plcmanual.com, n.d.)
The other form of communication is serial communication. The data is split into the constituents before transmitting and it is then transmitted one piece at a time. This form of communication is feasible for long range data transfer. This can be used for connecting a computer to a PLC. The standard for serial communication RS232 communications which is the most widely known and applied method connecting a plc to an external device communications. This is a communication interface that is included under applications of SCADA. The RS422 and RS423 are standards similar rs232 but they vary in the sense that these standards permit higher transmission rates and long cable distances. The RS232 devices are of two types. The DTE (data terminal equipment of which computer is an example.)And DCE (Data communications equipment of which modem is an example.). A plc can either be a DTE or a DCE device. (Plcmanual.com, n.d.)
ASCIIASCII is human-readable to a computer-readable translation code.In which each letter or number is translated to either 1’s or 0’s). It is a 7-bit code, so that we can translate 128 characters (2^7 is 128). (Plcmanual.com, n.d.)
The Flow of Data between the Member DevicesControl of the movement of data between two member devices in a database is very important. We need to know how the communication starts and ends, we also need to know the message content to be defined and monitored. This is called protocol and is to be maintained with both the devices involved in the networking process. This protocol can be tricky when several devices are connected with each other and their protocol needs to be compatible. In order to aid the protocol between different devices, the International Standard Organization (ISO in 1979 devised a model to be used for standardization for Open System Interconnection (OSI) (Plcmanual.com, 2014) (Plcmanual.com, n.d.)(c)Creation of databases storing data etc.

Section 4

Implications and methods
OPC Excel Reporter is used to transform your contemporary excel into tool used for reporting inventory and equipment data. With the help of the reporter, you can connect to a variety of data sources to prevent any serious loss of data. The technique of hardware handshaking is used. In this the flow of data in an interface is regulated by a signal that is being carried on separate wires .A simple example would be the the RTS (Request to Send) and CTS (Clear to Send) signals on a EIA-232 serial line. There is an alternative technique known as software handshaking, uses 2 very special characters that have been inserted in a data stream to carry out the same data

PART2

1. Panasonic FP0
The first PLC that I chose is the Panasonic FP0. The function of a Panasonic FP0 PLC is given below.
2. Data Types
The PLC supports all data types but due to the association with data acquisition and the measurement of temperature involved in this scenario, the real value interval scale data type is more frequently used. Atomic data is also present as constant update of room temperature is needed throughout the building but the atomic data might not become a part of the database and could be handled through the RAM. Other data types include Binary Coded Decimals etc.

Output Function

There are different kinds of output function employed by the controller.
Pulse output function
There are 2 channels for output of 10kHzpulses in the unit. The PLC can be also used for independent 2 axis. Positioning as the two channels can be separately controlled. It also returns automatically to home position and JOG operation can be easily executed once the automatic trapezoid control is set. This is done by the use of instructions that are designed for this operation.

High-speed counter function

In single phase the high-speed counter can deal with 4 channels, and for two phase 2 channels can be used. In the single phase, the total for 4 channels is 10 kHz, and for 2-phase the 2-channel total is 2 kHz total speed, thus making it useful as conveyor control and invertor control.

PWM output function

The PLC’s PWM (Pulse Width Modulation) output function with the support of a compact FP0 unit can make it possible for us to provide a temperature control.

Serial communication function

Connection with Operations Display. The FP0’s second RS232C port (types C10CRS, C16C, C14CRS, C32C, and T32C) allows a connection to the computers and the operations display. Data communication with devices like barcode readers and related Rs232c devices is also possible. The relay type and the transistor output type control units are both equipped with the 2nd RS232C port.

Analogue control function

Different input and output channels featured on four different analogue modules makes analogue control much simpler. A 12 bits high 1/4000 I/O resolution is obtained though it has a very small size. It supports different I/O ranges once the DIP switches placed on the analogue I/O unit are set for simple operation.
3. Accessing Memory and functions
There are three different memory areas that can be accessed by the computer; Timers, relay counters and data registers. Index registers can be used to modify other parts of the memory,
4. Output Function
Pulse output function. There are 2 channels for output of 10kHzpulses in the unit. The PLC can be also used for independent 2 axis. Positioning as the two channels can be separately controlled. It also returns automatically to home position and JOG operation can be easily executed once the automatic trapezoid control is set. This is done by the use of instructions that are designed for this operation.

High-speed counter function

In single phase the high-speed counter can deal with 4 channels, and for two phase 2 channels can be used. In the single phase, the total for 4 channels is 10 kHz, and for 2-phase the 2-channel total is 2 kHz total speed, thus making it useful as conveyor control and invertor control.

PWM output function

The PLC’s PWM (Pulse Width Modulation) output function with the support of a compact FP0 unit can make it possible for us to provide a temperature control.

Connection with Operations Display

R232 port is used for connecting bar code readers and other input/output functions. The FP0’s second RS232C port (types C10CRS, C16C, C14CRS, C32C, and T32C) allows a connection to the computers and the operations display. Data communication with devices like barcode readers and related Rs232c devices is also possible. The relay type and the transistor output type control units are both equipped with the 2nd RS232C port.

Analogue control function

Different input and output channels featured on four different analogue modules makes analogue control much simpler. A 12 bits high 1/4000 I/O resolution is obtained though it has a very small size. It supports different I/O ranges once the DIP switches placed on the analogue I/O unit are set for simple operation.
1. The Simatic s7-1200

The Simatic s7-1200 is the other alternate to Mitsubishi FX series.

“The SIMATIC S7-1200 controller is modular, versatile, and compact and avidly fits a wide variety of applications. It has a flexible design, an interface that fulfils the highest standards of industrial communication and a full range of powerful integrated technology functions make this controller useful for systems.”(hmkdirect.com, n.d.).
2. Data Types
There are different data types supported by the controller like bit and bit sequences, Integer, Floating point real, Time and Date, Character and String, Array, Data Structure, Pointers and PLC Data Type.

Functions

Major functions of S7-1200 are:
“Simple starter solution, packages and introductions facilitate familiarization. It has uncomplicated operation: Powerful standard commands which are simple to use, coupled with the easy to use software, the programming overhead is reduced to a minimum.
Real Time Characteristics:Special interrupt functions and pulse outputs and fast counters permit use even with time-critical processes.” (Commcam Ltd, n.d).
3. Accessing Memory
There are 3 memory areas that can be accessed to store the user program, data and configurations needed to work with this PLC; Load memory, work memory and retentive memory. The common bit memory is 4 Kilo bytes but CPU 1215C has 8 Kilo bytes. The MRES button on the operator panel can be used to reset the memory. An extendable Simatic memory can also be used.
4. Communication
Communication through point to point connections is permitted by the modules of communication. For this purpose the RS232 and Rs485, which is used for physical transmission, are used. The transmission of data takes place in the Freeport which is mode of CPU. Protocols like the ASCII USS are used because they are a more user specific and bit oriented form of communication protocol.
Many connections can be made like the Field PG device and the PC’s can be connected via standard CAT5 cable. Other connections include those between PG and CPU of SIMATIC S7-1200 and also the connection of many devices via CSM 1277 Ethernet switch should also be noted. The PROFINET interface allows communication with Programming devices SIMATIC controllers Automation components and HMI devices. We will connect these devices in a network and then data can be shared within the network Many devices have to work together at times to accomplish a job likewise in order to control a machine at times more than one controller should be applied to the system. Therefore for this purpose the communication between these devices is important. For programming a PLC therefore communication should occur because the computer must interact with the PLC CPU for the transmission of the configuration and control logic before the running of the PLC. IT is therefore very essential to understand PLC communication. (plctutor.com, 2013).

Use of Converters in Energy Management

Work environment like that of an energy manager use for RS232 to RS485 converters. Reason being that these converters are used for multi-drop networks, which means that multiple rs485 devices can connect to a single computer. As many as 32 devices can be connected in a network in order to communicate on a pair of wires ground wire is included also. And if the RS485 repeaters are used this number increases even more. Half-duplex communication is the name given to this communication type. Quality RS485 converters have the ability to communicate this way up to 1200 meters. The RS485 converters is resistant to noise making it another reason as to as to why it is preferred in industries. Different methods of wiring are used the cables involve in these wirings have been explained .Twisted-pair cabling is often routed through a steel conduit. A Twisted pair is a form of cable that connects homes and businesses to telephone company. Two copper wires that are insulated are twisted around each other in order to lessen the crosstalk between wires. The connections on a twisted pair needs both wires. The twisted pair is sometimes installed in pairs of two or more that too in a single cable. In some locations e.g. business the pair is wrapped in a shield that acts as ground. The name for this is STP or shield twisted pair. The ordinary wires in our homes is UTP or unshielded twisted pair.
The coaxial cable makes High data rates transmission possible and doesn’t need the steel conduit to shield it. The coaxial cable has one physical channel that will carry the signal which is surrounded by another concentric physical channel. Both of these run along the same axis. The ground is the outer channel. Many such cables or coaxial tubes are placed in a single outer sheath coupled with repeaters information along great distance can be transmitted.
The last cable we will discuss is the Fibre optic. The advantage of Fibre -optic cabling is that it is resistant to noise, flexibility and small size. This is a technique that uses threads of glass or plastic in order to transmit data. A cable consists of a group of glass threads that are capable of transmitting a message that are modulated onto light waves. The advantages of Fibre optics over the other traditional metal communication lines. These optics have greater bandwidth than other metal cables. This results in them carrying an increased amount of data. The Fibre optic cables compared to metal cables are less susceptible to interference. These cables are thinner and much lighter than the metal wires. Digital transmission of data which is the natural form of computer data is possible compared to analogically transmitting data.
Many forms of communication are available and are discussed. Parallel communication is a form of communication in which parallel cables are used to transmit simultaneously the constituent bits of a word.
5. Comparison between PLCs
This results in data transmission at high speeds over short distances. When laboratory instruments are connected to a system this can be used. Comparing Mitsubishi FX to Panasonic FP0 we find that The Mitsubishi series has a higher price. But Mitsubishi has tag based addressing and reusable subroutines that FP0 doesn’t have. Comparing with Siemens PLC both have about the same characteristics but The Siemens PLC’s price plus software is lesser than that of Mitsubishi’s. A comparison between them is given below:

References

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Commcam Ltd, h. (n.d.). Siemens Simatic S7-1200 - Underwoods. [online] Ued.co.uk. Available at: http://www.ued.co.uk/news/siemens-simatic-s7-1200 [Accessed 23 Dec. 2014].
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Plcmanual.com, (n.d.). PLC Communications | PLC Manual. [online] Available at: http://www.plcmanual.com/plc-communications [Accessed 23 Dec. 2014].
PLCTutor.com, (2013). PLC Communications - PLCTutor.com. [online] Available at: http://www.plctutor.com/plc-communications.html [Accessed 23 Dec. 2014].
Team, E. (2007). What is Atomic Data | Online Learning. [online] Learn.geekinterview.com. Available at: http://www.learn.geekinterview.com/data-warehouse/data-types/what-is-atomic-data.html [Accessed 23 Dec. 2014]