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2 weeks ago

Modbus Serial Communications Protocol Making Data Acquisition and Management More Effective

Modbus is a very effective serial communications protocol, which is published by Modicon in 1979, the company later converted to Schneider Electrical . This module is basically used in programmable logic controllers (PLCs). Soon after its release, Modbus has become the simplest and most robust de facto communication protocol in industrial automation.

The major advantages making Modbus the default communication protocol for a wide spectrum of industries are;

It is custom developed to be compliant with all standards industrial applications.
Modbus is open source without royalty free, to be acquired and customised by anyone.
So easy to deploy and maintain.
Not much restrictions on vendors and users.

What Modbus does?

Modbus helps in enabling effective communication and data acquisition in an industrial network with many devices interconnected to the same network. A classic example for such data communication can be a system which measures the temperature and humidity in a plant and then communicating that result to a computer. Modbus is now mostly used to a supervisory computer which has a remote terminal unit (RTU) in a typical supervisory control and data acquisition (SCADA) system.

Building Modbus application unit

To build a Modbus application data unit, the users need to first initiate a Modbus transaction modality. This is a function which informs a server as to what kind of action to be performed. This works in a Master to Slave mode as when the Master sends a message to Slave, this function cold field informs the server on what action to be performed next. There are also options to define multiple actions simultaneously.

The Modbus messages on serial connections are constructed in such a way that it allows the receivers to detect the beginning and end of the message easily. Usually, to identify the start of a message, a colon sign ‘:’ is used. If you are planning to install Modbus, then a bit more intensive research about its functionality is high advised.

3 weeks ago

Industrial PC Touch Screen SCADA System Administration

PC Touch Screen based SCADA systems are now largely gaining in popularity. Not just that these are easy to operate, but there is a huge time and cost saving also with this when compared to the conventional use of navigation devices and pointers to operate a typical SCADA system.

There are various types of industrial panel PC touch screens available now which are compatible with SCADA HMIs. A few of the major options popularly used are as below.

Low power consuming fan-less models.
Low-profile PC touch screen models ranging 8 inch to 19 inch
Resistive 5-wire touch screen
2.0 GHz Quad Core processor
LAN (1), COM (2), USB (4) interfaces
Windows 7 Embedded OS, to name a few.

Touch screen PC

PClog is one of the most popular model low-power fan-less PC, which is custom designed from front panel mounting. It features 4/5-wire resistive touch screens, which are so easy to comfortable to use. There are various models available in this range with screen sizes as 8.4", 15", 17", 19" etc.

The latest PC Touch Screens have J1900 Quad Core CPU, which is highly powerful, four USB interfaces, one Ethernet interface, and two RS232 serial interfaces. This application is meant ideally for the industrial applications and installed with Windows 7 Embedded OS (WES7), which ensures higher memory, speed, and reliability.

Windows 7 Embedded OS ensures;

Faster booting and log in.
Considerable reduction in footprint
Application memory and write protection
Reduced cost when compared to other versions

SCADA Software compliant with PC touch screen

Winlog Pro is a flexible and convenient software package to be clubbed with PC touch screen applications. An integrated development environment offers a custom set of tools for intuitive creation of multi-language applications and make SCADA system administration so easy for the operators.

 

4 weeks ago

Industrial PC Touch Screen SCADA System Administration

PC Touch Screen based SCADA systems are now largely gaining in popularity. Not just that these are easy to operate, but there is a huge time and cost saving also with this when compared to the conventional use of navigation devices and pointers to operate a typical SCADA system.

 

There are various types of industrial panel PC touch screens available now which are compatible with SCADA HMIs. A few of the major options popularly used are as below.

 

Low power consuming fan-less models.

Low-profile PC touch screen models ranging 8 inch to 19 inch

Resistive 5-wire touch screen

2.0 GHz Quad Core processor

LAN (1), COM (2), USB (4) interfaces

Windows 7 Embedded OS, to name a few.

 

Touch screen PC

 

PClog is one of the most popular model low-power fan-less PC, which is custom designed from front panel mounting. It features 4/5-wire resistive touch screens, which are so easy to comfortable to use. There are various models available in this range with screen sizes as 8.4", 15", 17", 19" etc.

 

The latest PC Touch Screens have J1900 Quad Core CPU, which is highly powerful, four USB interfaces, one Ethernet interface, and two RS232 serial interfaces. This application is meant ideally for the industrial applications and installed with Windows 7 Embedded OS (WES7), which ensures higher memory, speed, and reliability.

 

Windows 7 Embedded OS ensures;

 

Faster booting and log in.

Considerable reduction in footprint

Application memory and write protection

Reduced cost when compared to other versions

 

SCADA Software compliant with PC touch screen

 

Winlog Pro is a flexible and convenient software package to be clubbed with PC touch screen applications. An integrated development environment offers a custom set of tools for intuitive creation of multi-language applications and make SCADA system administration so easy for the operators.

1 month ago

SCADA Systems – A Few Things for the Beginners to Know

SCADA refers to a centralised system, which is meant to monitor and control complex industrial systems distributed over an extensive area. A typical SCADA system can act as a decisive link between an industrial plant and its distribution network. Say for example, a typical SCADA system will ensure adequate functioning of a power plant and the distribution network of national power grids.

SCADA control functions

The host control functions of SCADA systems are usually restricted to supervisory level interventions. Say for example, a typical PLC system may be used to control the flow of coolant to a section or the plant, whereas a SCADA system will enable the operators to alter the set points to plan the flow and set alert conditions to be recorded. The major advantage of SCADA is that it enables remote administration, which when integrated with PLC makes management of a large plant just a breeze.

SCADA subsystems

A typical SCADA system comprises of many subsystems as;

An HMI (Human-Machine Interface), which is an apparatus that processes data for the human operators to take informed decisions.

A computer system to acquire data and process it to send commands.

Remote terminal unit/s (RTUs), which ideally connects to the sensors to access the signals and convert it to digital data to be sent to the supervisory system.

Programmable Logic Controllers (PLCs), which are field devices for various purposes that can be customised based on purpose.

Communication infrastructure to connect the supervisory system to remote terminal units to access data and transfer information.

SCADA systems are usually comprised of a widely distributed database that is known as tag database. Such databases are made of elements called tags or points. An element represents a single input or output (I/O) value, which is monitored or controlled using the central system.

Overtime, SCADA systems are largely advanced and now there are web-based and cloud-based SCADA applications to ensure more flexibility, customisability, and these also eradicate the previous restrictions on geographical restrictions, time constraints, and accessibility.

 

2 months ago

Scada- The New Age Automation Solution

What is SCADA?

SCADA stands for Supervisory control and data acquisition. It is a remote monitoring and control system that works with the help of coded signals through communication channels. The system uses usually a single communication channel for every remote station.

USES

SCADA finds its use in the core of modern industry where it basically works as an industrial automation control system. It is used in the many industries. Some of them are as follows:

 Food and beverage

 Energy

 Oil and gas

 Recycling

 Transportation

 Water and waste water

 Manufacturing

 Power

SCADA systems are used in large as well big industrial units both in private and public sector undertakings. This is possible because these systems are highly flexible. They can be simple and complicated which makes them fit for various industrial automation systems that may be needed for large and complex projects.

In fact SCADA has become indispensable to all types enterprises ad are adding in the smooth running of the operations. It is implemented in supermarkets, waste water treatment plant, refinery and even in many households.

How does it work?

Several hardware and software elements are implemented to monitor, accumulate and process data. With the help of this automated system, it is possible to interact and operate variety of machines and wide range of devices including motors, valves, pumps and more. These machines and devices are connected to HMI (human-machine interface) software.

All events are recorded in a file which makes it easier to track down any errors in case of a snag.

Information can be provided either manually or through sensors which are then sent to RTUs (remote terminal units) or PLCs (programmable logic controllers).  The SCADA software loaded in computers then processes this information. The raw data is analyzed to help operators derive meaningful information that helps them to eliminate waste and make the operations more efficient.

Since the manufacturing processes are refined there is savings in terms of money and time.

 

2 months ago

Scada- The New Age Automation Solution

What is SCADA?

SCADA stands for Supervisory control and data acquisition. It is a remote monitoring and control system that works with the help of coded signals through communication channels. The system uses usually a single communication channel for every remote station.
 
USES

SCADA finds its use in the core of modern industry where it basically works as an industrial automation control system. It is used in the many industries. Some of them are as follows:

 Food and beverage
 Energy
 Oil and gas
 Recycling
 Transportation
 Water and waste water
 Manufacturing
 Power

SCADA systems are used in large as well big industrial units both in private and public sector undertakings. This is possible because these systems are highly flexible. They can be simple and complicated which makes them fit for various industrial automation systems that may be needed for large and complex projects.

In fact SCADA has become indispensable to all types enterprises ad are adding in the smooth running of the operations. It is implemented in supermarkets, waste water treatment plant, refinery and even in many households.

How does it work?

Several hardware and software elements are implemented to monitor, accumulate and process data. With the help of this automated system, it is possible to interact and operate variety of machines and wide range of devices including motors, valves, pumps and more. These machines and devices are connected to HMI (human-machine interface) software.

All events are recorded in a file which makes it easier to track down any errors in case of a snag.

Information can be provided either manually or through sensors which are then sent to RTUs (remote terminal units) or PLCs (programmable logic controllers).  The SCADA software loaded in computers then processes this information. The raw data is analyzed to help operators derive meaningful information that helps them to eliminate waste and make the operations more efficient.

Since the manufacturing processes are refined there is savings in terms of money and time.

 

4 months ago

The first steps in understanding Modbus

Electronic devices communicate with each other by using a language that is termed as Modbus. Truly speaking, it is a communication protocol or messaging structure, which is not the language itself but the method of communication. Devices that are connected to the same network can communicate with its help. This is widely perceived in SCADA systems where the communication between the remote computer and the RTUs are performed by it. Since the computer, which can be a PC touch screen, is seeking information from the RTUs, the computer is the Master and the RTUs that supply the information are considered Slaves.  Indeed, this is what has been laid down in the protocol. There can be only a single master that has the ability to look after 247 slaves. Being the Master, it can command the Slaves through written information to the salves that have to act accordingly.

RS-485 – Modbus RTU

Things are likely to get a bit technical but don’t worry, it will be simplified as much as possible. RTU is the most popularly used network that has a Master and a single or many slaves but not more than 247. Each slave is designated by a unit number that corresponds to a unique device address of 8 bit. The Master sends information packets that bear the Slave’s address for whom it is meant. As soon as the packet reaches the slave, after verifying the address, it is its turn to respond but within a specified time.  If no response is received by the master within that time it considers the activity as a no-response error.

What are registers?

The information exchange that comprises of writing and reading data is compiled in 16 bit data pieces which are known as registers. The register is usually a 16 bit integer that may or may not be signed. If a floating point of 32 bit integer is required it is obtained by combining two registers. The values are read in the form of a pair of registers.  The Holding Register is most commonly used or writing as well as reading. There is another read-only register named Input Register.

What are coils?

Coils and discrete input are registers but with exceptions to the standard 16 bit registers because these are of a single bit only. Discrete inputs are read-only type while coils can both be read and written. Coils are normally related to relay outputs. The types of registers to be included in a system depend on the manufacturer.

Function codes

The function code is responsible in determining which type of register is being addressed by a specific Modbus request.  “Read holding registers” is denoted by the numerical code 3 and 1 denotes “may read”. To write a “single holding register” you have to use 6 as the function code. For writing one or more holding registers function code 16 has to be used.

A Modbus RTU (RS 485) can have one Master only and if the gateway is the Master, you can have one gateway only.