Showing posts with label Industrial Communication. Show all posts
Showing posts with label Industrial Communication. Show all posts

Friday, December 7, 2018

How to upgrade your Legacy Equipment for industry 4.0

Scholar and leadership expert Warren Bennis once said, “In life, change is inevitable. In business, change is vital.” This wisdom resonates with every business owner, but none more than the manufacturer.
We are in the midst of a new industrial revolution, one which will significantly impact the manufacturing industry. Experts are calling it Industry 4.0, the fourth wave in the industrial revolution behind steam power, electricity and computing.
According to TechRadar, Industry 4.0 is “the label given to the gradual combination of traditional manufacturing and industrial practices with the increasingly technological world around us.” Industry 4.0 is ushering in a new era of production where automation and data exchange are integrated into the manufacturing process to streamline productivity.
Sounds great, right? It is, if you can upgrade your legacy equipment. Nobody enjoys the process of upgrading, let alone talking about it, but this is a revolution you don’t want to miss. Here’s how you can upgrade your legacy equipment to successfully ride the wave of Industry 4.0. 
Industrial Internet of Things
The Industrial Internet of Things (IIoT) is the interconnection between manufacturing and production equipment. This equipment uses sensors and internet connectivity to communicate with themselves and one another to create a more efficient production output. As a result, equipment can consider factors like stress on the electrical grid and projected weather to determine the most efficient way to operate at any given time.
According to Gartner, a leading research and advisory company, more than half of major new business processes and systems will incorporate some element of the IIoT by 2020. What’s more, McKinsey Global Institute reported that in the last five years, the number of connected machines has grown by 300 percent.
These businesses are onto something; there are many benefits of integrating the IIoT into manufacturing processes. Information gleaned from the IIoT provides access to real-time data and insights on equipment’s performance and use. Operators can also closely track the lifespan of their machinery in order to proactively plan for maintenance and upgrades. IIoT integration also aids in the automation process. Digitally connecting the machinery creates a mesh that seamlessly translates into full automation. Finally, clients can more readily track the progress of their order with insights provided by the IIoT.
Integrating the IIoT with existing equipment can be challenging, but it isn’t impossible. Most legacy equipment can be retrofitted with sensors and other online monitoring devices.
Smart Factories
In the past, many manufacturing facilities relied on Manufacturing Operations Management (MOM) software to integrate the many independent facets of the production process. Unfortunately, this technology is not able to manage production processes in real-time.
Smart Factory software integrates every part of the production process, including production, resources, supply chain, maintenance and human resources, in order to create a single, efficient output.
This technology enables factory managers to examine data once unavailable, informing decisions about production and other business processes. With Smart software, operators can be more responsive to several factors, including resource availability and cost, consumer demand, market fluctuations, and more. 
Wireless HART network
An Example of Wireless HART mesh network

Digital Supply Chains
Digital supply chains aren’t simple A to B, B to C, C to D processes. In these systems, relationships between different parts of the overall production process are affected by changes or events elsewhere in the system and able to adapt to those changes.
To create a truly digital supply chain, the facility must consider all factors that could potentially impact each part of the supply chain, all the while remedying any issues that may impede the supply chain from operating as designed. Insights from a digital supply chain give manufacturers a real-time overview of every link in the supply chain. As a result, they can quickly respond to problems and simulate scenarios to proactively plan for the future.
To do this well, factories must integrate every step of the product life cycle. This includes everything from sourcing and shipping raw materials, to ordering packaging, advertising the product, and scheduling employees on the factory floor. The digital supply chain system acknowledges that creating a product isn’t black and white. It is a highly sophisticated process that involves many interconnected variables.
Industry 4.0 is here to stay. Upgrades can cause growing pains, but in the end, change is almost always a good thing. Be a part of the next industrial revolution. Integrate your equipment and transform your business.
About the Author:
Page Long is the Marketing Operations Director at PDF Electric & Supply, which is based out of Cary, NC. PDF Electric & Supply is an automation supplier specializing in Legacy GE PLCs.
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Wednesday, September 26, 2018

How HART Communication Protocol is used in Industrial Measurement

HART (Highway Addressable Remote Transducer) communication protocol is a hybrid of both the analog and digital industrial communication open protocol. HART communicates digital data along the loop conductors in the form of AC signals (audio-frequency tones) superimposed on the 4-20 mA DC current signals. A modem built in the smart transmitter translates these AC signals into binary bits and vice versa.

By connecting a HART communication device at any point along the two-wire cable, any instrument technician can easily configure the transmitter.  Being able to communicate digital data over the same wire pair as the DC power and analog signal makes it possible to communicate self-diagnostics information, alarms, status reports; multiple process variables for example temperature, density etc. to the control system in addition to the original analog signal representing the main process variable. The control system can also communicate to the transmitter using the same digital protocol for example switch between measurement range sets etc. The only limitation of digital communication is the data rate or speed, and not the quantity of the data being transmitted.

The use of HART doesn’t make any changes to the normal series connected circuit configuration of the transmitter, DC supply, and resistor. A HART enabled transmitter is equipped with a inbuilt digital microcontroller managing its functions, and this microcomputer is able to send and receive digital data as AC signals (current pulses in sending mode, voltage pulses in receiving mode) superimposed on the same two wires carrying the 4-20 mA analog signals and DC power.

Any computer device equipped with a HART modem, the configuration software, device description, for that particular instrument may communicate with the HART transmitter if connected in parallel with the transmitter’s loop power terminals.

How HART Communication Protocol is used In Industrial Control

This external computer through the use of HART data transmission, can now monitor details of the transmitter’s operation, configure the transmitter, make changes to its measurement ranges among other additional functions.
The HART modem can be connected anywhere in the circuit electrically parallel to the HART-enable transmitter’s terminals.

How HART Communication Protocol is applied in industrial Control

This flexibility works to the advantage to the instrument technicians enabling them to connect the HART configuration instrument at the most physical convenient location.
HART communicators are battery powered, portable devices built specifically for configuring HART-enabled field instruments. Like PCs they need to be updated with DD files to be able to communicate with the latest models of HART-enabled field instruments.

Key Features of HART communication Protocol includes:
  • Changes to field instruments ranges can be made remotely with the use of HART communicators.
  • Field instruments may be programmed with identification data e.g. tag numbers, corresponding to plant-wide instrument loop documentation.
  •  Diagnostic data may be transmitted by the field device for example out of limit alarms, preventing maintenance alerts, self-test results etc.
  • Technicians may use HART communicators to force field instruments into different manual modes for diagnostic purposes e.g. forcing a transmitter to output a fixed current so as to check calibration of other loop components, manually stroking a valve equipped with a HART capable positioner.



Merits of HART Protocol
HART technology has allowed new features and capabilities to be added on to existing analog signal loops without having to upgrade wiring or change all the instruments in the loop.
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Demerits of HART Protocol
The main disadvantage of HART data communication is the slow speed.  Its bit rate of 1200 bits per second is slow for modern standards.

Monday, September 17, 2018

Foundation Fieldbus and Profibus

Before we look at Foundation Fieldbus (FF) and Profibus let’s find out why digital signals are commonly used in industrial data transmission.
Digital signals can be transmitted without loss of integrity, via a hardwired parallel or serial bus, radio transmitter or fiber optics.
Digital data transmission speeds are higher than with analog data transmission.

Digital signals can be transmitted without loss of accuracy and can contain codes for limited automatic error correction or for automatic requests of data retransmission.
Digital transmitters consume less power as compared to analog transmission devices hence they are preferred for use in industrial communication systems over analog devices.

Foundation Fieldbus and Profibus
The Foundation Fieldbus (FF) and Profibus are the two most universal serial data bus formats that have been developed for interfacing between central processor and smart sensing devices in a process control system.
The FF is primarily used in the USA and the Profibus is primarily used in Europe.
Process control equipment is presently manufactured to accept either of these formats.
A serial data bus is a single pair of twisted copper wires, which enables communication between a central processing computer and many monitoring points and actuators when Smart Sensors are used.
Foundation Fieldbus Cable Connection

Although initially more expensive than direct lead connections, the advantages of the serial bus include: Minimal bus cost and installation labour. The system replaces the leads to all the monitoring points by one pair of leads. New units can be added to the bus with no extra wiring i.e. plug and play feature, giving faster control. Programming is also the same for all the systems.
The accuracies achieved are higher than from using analog, and more powerful diagnostics are available.
The bus system uses time division multiplexing, in which the serial data word from the central processor contains the address of the peripheral unit being addressed in a given time slot, and the data being sent.
In the FF, current from a constant current supply is digitally modulated. Information on the FF is given in the ISA 50.02 standards.
One drawback of the FF is that a failure of the bus, such as a broken wire, can shut down the entire process, where with the direct connection method, only one sensor is disabled. This disadvantage can be overcome by the use of a redundant or backup bus in parallel to the first bus, so that if one bus malfunctions, then the backup bus can be used
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Monday, September 10, 2018

How Digital Communication Technology is applied in Measurement and Control Systems

The continued advancement in digital technology has revolutionized how data is acquired in measurement and control instruments. Data acquisition in instrumentation systems encompasses the measurement and recording of process data.
The ability of being able to relay or communicate large amounts of data over a limited number of channels gives digital technology an upper hand over Analog technology. For example in Analogy technology where  4-20 mA or 3-15 PSI signals are used, each pair of wires can communicate only one variable whereas in digital networks, one pair of wires can communicate a limitless number of variables, with the only limit to it being the speed of that data communication.
From the above, 4-20 mA analog signals can be expensive to utilize in especially for an instrument generating multiple variables of measurement like Coriolis mass flowmeters that measures Flow rate, density, and temperature at the same time. In this case you will need dedicated wire pair for each process variable. Digital Technology overcomes these shortcomings of 4-20 mA analog signals.
One solution to this problem is using HART digital signals superimposed on 4-20 mA signals; we normally call this 4-20 mA plus HART. With this, you retain the analog signals while at the same time enjoying the multi-variable communication benefits that comes with digital technology however wired-HART communication is rather slow by any standard, and this restricts its use to maintenance {range changes, diagnostic data polling} and used only for slow process control processes.
Magnetrol Level Transmitter Configuration using Pactware

Examples of digital communication standards include:
  • Modbus
  •  HART
  •  FOUNDATION Fieldbus
  • Profibus PA
  • Profibus DP
  • Profibus FMS
  • AS-I
  •  ControlNET
  •  DeviceNet
  • BACnet
  • LonWorks
  • CANbus
Some of the digital communication instruments find common use in distributed control systems (DCS) applications.
SCADA (Supervisory, Control and Data Acquisition) systems use digital communication technology. SCADA is similar to DCS, but it is spread over a large geographical area whereas DCS may cover only a plant floor. You will find SCADA systems applied in areas like:
  •  Gas and oil exploration and distribution (pipeline) systems
  • Electric power generation and distribution (power line, substation) systems.
  • Water and wastewater treatment and distribution lines (water line, pumping stations) systems.
  • Large irrigation or harvesting systems.
The process data in a SCADA system is sensed by various measurement devices (transmitters) converted to digital form by an RTU (Remote Terminal Unit), and communicated to one or more MTUs (Master Terminal Units) at a central location where we have human operators monitoring the data and at the same time make command decisions.
In a system where we have the flow of information just in one way (simplex) from the measurement devices to human operators, the system may be referred to as a Telemetry system rather than a SCADA system.
SCADA implies two-way (Duplex) information flow, where human operators not only monitor the process data but also issue commands back to the remote terminal units to effect change.
Actually the need of remote monitoring and control of electric power distribution systems lead to the development of power line carrier analog telemetry systems. These systems superimposed high-frequency (50 kHz to 150 kHz) carrier signals on a low-frequency (50 Hz and 60 Hz power line conductors to communicate basic information like human voice (telephone network dedicated to power system operators), power flow (MVAR meter, Wattmeter) monitoring and protective relay (automatic trip) controls. These are examples of telemetry systems that were among the first to benefit from digital technology.
Large scale power systems cannot be operated safely and with efficiency without the use of remote data monitoring and control systems.

You can also read: How to integrate PLC into a Control System

The bottom line
From the above discussion, you can see that digital communication technology forms an essential part of any modern measurement and control system, and as more research and development is being done in the digital field, industries will continue to use this technology to improve efficiency in their industrial production and processing systems.
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