Category Archives: Industrial Automation

What Is Industrial Automation?

Posted on by
Reply

Industrial automation is the use of computer‑based control systems, or sometimes even analog ones. It’s about letting machines manage themselves with minimal human intervention.
It involves using machines, robots, and software to perform tasks that usually back then were performed by humans.

Core Components & How It Works

At the core of industrial automation systems are devices and technologies that monitor, control, and execute tasks, replacing or reducing the need for human intervention.

This includes hardware like PLCs (Programmable Logic Controllers), sensors, actuators, robotic arms, HMIs (Human-Machine Interfaces), and software systems such as SCADA (Supervisory Control and Data Acquisition) and DCS (Distributed Control Systems).

PLCs are industrial-grade computers that take input from sensors (such as temperature, pressure, or position sensors), execute programmed logic, and drive actuators (like valves, motors, or lights) accordingly.

The control strategy can be simple—such as turning off a motor when a temperature threshold is reached—or complex, such as coordinating an entire assembly line with hundreds of input/output points.

This is where SCADA systems or DCS platforms come in: they gather data from multiple PLCs or controllers, offer visualization dashboards, allow operators to supervise and control processes remotely, and provide historical logging for quality assurance and diagnostics.

Another major component is CAD/CAM (Computer-Aided Design and Manufacturing), which not only designs parts but also feeds into CNC (Computer Numerical Control) machines and automation paths. This seamless integration is a hallmark of advanced automation.

This control can be analog (e.g., pneumatic regulators, PID loops using analog signals) or digital (as in PLCs).

The ultimate goal remains the same: orchestrate all system components to operate autonomously and precisely.

Types of Industrial Automation

Industrial automation isn’t one-size-fits-all. Depending on production needs, scale, and complexity, different types of automation systems are implemented. These fall into four primary categories:

Fixed (Hard) Automation

This type is designed for high-volume, repetitive tasks. The machinery is configured for a specific process and cannot be easily changed.

Examples include automotive assembly lines or bottling plants. Fixed automation is known for high throughput but lacks flexibility.

Programmable Automation

Here, machinery can be reprogrammed to accommodate changes in product design or production sequence.

It’s widely used in batch production, for example, in chemical or food industries. Reprogramming takes time and cost, but it offers more adaptability than fixed automation.

Flexible (Soft) Automation

Flexible systems, often found in CNC machining and robotic systems, can easily switch between different product types.

The transition requires little to no downtime. This is where robots with vision systems, AGVs (Automated Guided Vehicles), and flexible manufacturing systems shine.

Integrated Automation

This is the future-focused approach combining all levels, from field devices to enterprise resource planning (ERP).

It leverages digital communication, centralized control, and software platforms like MES (Manufacturing Execution Systems) and IIoT (Industrial Internet of Things).

Integrated automation enables real-time data-driven decision-making, predictive maintenance, and seamless cross-system interaction.

Each automation type reflects a different degree of self-management and adaptability. The more integrated and flexible the system, the closer we get to fully autonomous industrial environments.

Benefits & Impact

Industrial automation makes machines run themselves, reducing human involvement to the essentials.
It enhances accuracy, efficiency, productivity, and safety while lowering operational costs.
It will increase accuracy, efficiency, productivity, and safety, and at the same time, we reduce the operational cost for our factories.
Automation frees workers from dangerous or monotonous tasks, enabling them to focus on higher‑value roles.

Enabling Trends: Industry 4.0 & IIoT

Industrial automation is being revolutionized by the Fourth Industrial Revolution, Industry 4.0, with smart devices, M2M communication, AI, and cloud integration.
Concepts like IIoT, digital twins, machine learning, and industrial robotics make production smarter, safer, and more adaptable.

Safety, Challenges & Future Outlook

Using PICs and SCADA in safety‑critical environments requires robust protocols and regulatory compliance. Cybersecurity risks (e.g., PLC vulnerabilities) are significant.

High upfront costs and complexity of integration can be barriers, yet trends like flexible and integrated automation systems lower these hurdles.

Looking ahead, expect growth in AI-driven automation, digital twin simulations, and fully lights-out smart factories.

FAQ: What Is Industrial Automation?

What is an example of industrial automation?

A classic example of industrial automation is a robotic assembly line in an automotive plant.

Robots handle tasks like welding, painting, or assembling parts with minimal human oversight.

These systems rely on PLCs, sensors, and actuators to perform repetitive actions with speed and precision.

What is automation in the industry?

Automation in the industry refers to the use of machines, software, and control systems to perform tasks that traditionally required human labor.

This includes monitoring processes, adjusting equipment, handling materials, and even making decisions based on real-time data.

What are the four types of industrial automation?

The four primary types of industrial automation are:

  1. Fixed Automation – High-volume, repetitive tasks (e.g., vehicle assembly lines).
  2. Programmable Automation – Customizable control systems for batch production.
  3. Flexible Automation – Rapidly adjustable systems for varying products.
  4. Integrated Automation—Fully networked and data-driven production environments.

Each of these represents a different approach to reducing manual labor and enhancing production flexibility.

These systems scale from rigid to highly adaptive setups depending on the industry’s needs.

What is a PLC in automation?

A PLC (Programmable Logic Controller) is a rugged industrial computer used to automate processes by monitoring inputs and controlling outputs based on a custom logic program.

They’re essential in managing repetitive tasks like turning motors on/off, adjusting valves, or reading sensor signals.

In practical use, “the use of PLC” is one of the most fundamental tools in industrial automation.

These controllers provide the decision-making brain of the system, ensuring operations run smoothly and according to programmed logic—even in harsh industrial environments.

Conclusion: What Is Industrial Automation?

Industrial automation means letting machines self-manage critical processes. It combines PLCs, robots, sensors, control systems and software to deliver safer, more accurate, efficient, and lower-cost operations.

As IIoT, robotics and AI advance, automation will only deepen its impact across industries.

How To Design A Gas Detection System For Boiler Rooms

Posted on by
Reply

We commonly use natural gas for heating in industrial complexes; undetected gas leaks or incomplete combustion could cause an explosive hazard or an influx of carbon monoxide, resulting in loss of life, structural damage, or expensive waste of fuel.

Why do we need a gas detection system for boiler rooms?

The boiler room is not frequently occupied; this may lead to the leak remaining undetected.

A continuous gas monitoring and detection system will provide early warning of a gas leak and prevent loss of life and material.

What gases can be found in boiler rooms?

Natural gas

Natural gas is used in the industry for heating, and undetected leaks can be deadly. Nearly half of the natural gas is methane.

Since natural gas is lighter than air, it will immediately rise to the ceiling or roof space of the boiler room.

Carbon Monoxide

Carbon monoxide is the result of the incomplete burning of hydrocarbon fuels such as wood products, natural gas, fuel oil, and coal.

For this reason, carbon monoxide and natural gas monitoring are essential for gas detection in boiler rooms.

Components of Boiler room gas detection system

How To Design A Gas Detection System For Boiler Rooms

The boiler room’s gas detection system consists of sensors that are strategically placed to detect natural gas and carbon monoxide, with a controller that will have relays or that can connect to an external system.

Gas sensors

I recommend selecting catalytic bead sensors for boiler room applications. Catalytic bead sensors are less prone to false alarms than solid-state or semiconductor sensors.

Catalytic bead sensors have a life expectancy of 3 to 5 years, sometimes even more depending on how well you take care of them and environmental factors like temperature and humidity.

Boiler rooms are considered safe areas, i.e., you do not need explosion-proof sensors, but it is recommended to use them, and if possible, use class I Div I sensors.

My recommendation for this would be Sensepoint XCD or E3point, both manufactured by Honeywell.

Location of the sensors

Natural gas is lighter than air, which means the gas will concentrate near the roof, so my recommendation would be to place at least one sensor on the roof (typically one foot from the roof), and the rest of the sensors should be located over potential leak areas.

This includes

  • The gas burner assembly.
  • The gas train assembly.
  • The pressure boosters (if boosted).
  • The gas shut-off valve.
  • The combustion air intake.
  • The gas meter.

Depending on the size of the boiler room, the rule of thumb is to install one sensor for each 25 feet of radius.

The controller

It is recommended to have at least one controller in the boiler room; as its name suggests, the controller will be the main brain of the gas detection system. You can set it up to shut down the valves, activate relays, or activate the horn and strobe.

Here are my recommendations when it comes to selecting a controller for the boiler room gas detection system.

Location of the controller

I recommend having a controller outside the boiler room so that people can see what is going on in the boiler room before they enter it.

Compatible with the sensors

I have seen people buy sensors from one manufacturer and the controller from a different one, or the same manufacturer, but they are incompatible.

Make sure the sensors you have can communicate with the controller; if you have 4-20 mA sensors, you need a controller that can take 4-20 mA input; if the sensors are Modbus, make sure the controller can accept Modbus inputs.

The controller must have relays

Depending on what you want to do, you may need a controller with relays; this can be to shut down a control valve, start or stop a fan, process, etc.

Power Supply

Most controllers run on 24 VDC; make sure that you have the power supply that can help the sensors and the controller.

Visible Display

I recommend a controller that has a visible display so that people can be able to see the reading in real-time.

Integration Options

Depending on whether the boiler room gas detection system is stand-alone or is integrated with a larger system.

If you are going to connect it to a building management system (BMS), you probably need a controller that has BACnet (Building Automation Control Network) protocol as an output.

FAQ: Gas Detection System For Boiler Rooms

What detector do you need for a boiler room?

You need two types of detectors for carbon monoxide and flammable gases (LEL).

How many sensors do I need for a boiler room?

It depends on how many potential leaks there are; I recommend one per potential leak. Make sure the sensors are placed near the potential leak.

Is a carbon monoxide detector required in a boiler room?

Each boiler room containing one or more boilers from which carbon monoxide can be produced shall be equipped with a carbon monoxide detector with a manual reset.

Key takeaways: Gas Detection System For Boiler Rooms

Most industries, including boiler rooms, use natural gas for heating; this poses the danger of explosion due to the natural gas leak, or the unburned gases can turn into carbon monoxide.

To design a gas detection system for boiler rooms, you need to consider sensors that will detect methane (LEL sensors) and carbon monoxide.

I recommend using electrochemical sensors because they have an expected life of 3 to 5 years and produce fewer false alarms.

You need to place the sensors near the position where there is more possibility of a leak and the controller outside the boiler room where it is visible so that people can see the reading before they enter the boiler room.

Bimetallic Strip – Everything You Need To Know

Posted on by
Reply

Bimetallic strips are an ingenious invention that harnesses the different expansion rates of two metals to perform a variety of tasks.

At its core, a bimetallic strip is made by bonding two strips of different metals together. These metals expand at different rates when heated, causing the strip to bend.

This simple principle has given rise to numerous practical applications.

The history of bimetallic strips

The story of bimetallic strips begins with John Harrison, an 18th-century clockmaker who revolutionized timekeeping.

By using bimetallic strips in his marine chronometers, Harrison was able to correct the timekeeping errors caused by temperature fluctuations, which was a game-changer for navigation at sea.

Fast forward to today, and bimetallic strips are everywhere. You’ll find them in thermostats, where they help control heating and cooling systems, and in electrical devices, acting as a safeguard against overheating.

In industrial settings, they’re crucial for various sensors and automatic controls, ensuring machines operate smoothly and safely.

The choice of metals is crucial—typically, a high-expansion metal like brass or copper is paired with a low-expansion metal like steel.

This combination creates the desired thermal sensitivity, making the strip bend predictably in response to temperature changes.

In essence, bimetallic strips are a brilliant blend of materials science and thermal engineering.

Their straightforward design and reliable performance make them a cornerstone in both everyday gadgets and sophisticated industrial systems.

What Is A Bimetallic Strip?

A bimetallic strip is a fascinating little device composed of two different types of metals bonded together.

These metals have different coefficients of thermal expansion, meaning they expand and contract at different rates when exposed to temperature changes.

When the temperature changes, one metal expands or contracts more than the other, causing the strip to bend or curve.

This bending action can be used to measure temperature changes or to act as a switch in various applications.

You’ll often find bimetallic strips in thermostats, where they help control heating and cooling systems by responding to temperature changes.

They’re also used in electrical devices as thermal protectors, shutting down circuits when things get too hot.

In industrial settings, they’re crucial components of sensors and control systems, ensuring safe and efficient operation.

In essence, a bimetallic strip is a simple yet incredibly effective way to harness the physical properties of metals for practical applications.

Who Invented The Bimetallic Strip?

The bimetallic strip was invented by John Harrison, an English clockmaker, in the mid-18th century.

Harrison developed the bimetallic strip for his third marine chronometer (H3) in 1759 to compensate for temperature-induced changes in the balance spring.

This invention significantly improved the accuracy of timekeeping, which was crucial for navigation at sea.

How Does a Bimetallic Strip Work?

A bimetallic strip operates on a simple yet effective principle that leverages the differing thermal expansion rates of two metals.

Here’s a detailed explanation of how it works:

Composition

A bimetallic strip is made by bonding two thin strips of different metals together. These metals are chosen because they have distinct coefficients of thermal expansion, meaning they expand and contract at different rates when exposed to temperature changes.

Thermal Expansion

When the temperature changes, each metal expands or contracts by a different amount. If the temperature increases, the metal with the higher coefficient of thermal expansion (let’s call it Metal A) will expand more than the metal with the lower coefficient (Metal B). Conversely, if the temperature decreases, Metal A will contract more than Metal B.

Bending Action

Because Metal A and Metal B are bonded together and can’t move independently, this difference in expansion rates causes the bimetallic strip to bend. When heated, the strip bends towards the metal with the lower coefficient of thermal expansion (Metal B). When cooled, it bends towards the metal with a higher coefficient of thermal expansion (Metal A).

What is a Bimetallic Strip Used For?

Bimetallic strips are incredibly versatile and find application in a wide range of fields due to their ability to convert temperature changes into mechanical movement. Here are some of the primary uses:

Thermostats

One of the most common applications of bimetallic strips is in thermostats. In these devices, the strip bends in response to temperature changes, either closing or opening an electrical circuit.

This action regulates heating and cooling systems in homes, appliances, and industrial equipment, maintaining a desired temperature.

Thermal Switches

In electrical devices, bimetallic strips serve as thermal protectors. When a device overheats, the strip bends, breaking the circuit and preventing further heating. This helps in avoiding damage to the device or potential fire hazards.

Thermometers

Bimetallic strips are used in dial thermometers, where the bending of the strip is converted into a rotary motion that moves a needle across a scale to indicate temperature. These thermometers are simple, durable, and do not require batteries or external power.

Industrial Controls

In industrial settings, bimetallic strips are integral to various sensors and control systems. They help in monitoring and regulating the temperature of machinery and processes, ensuring operational safety and efficiency.

Clocks and Chronometers

The invention of bimetallic strip was invented by John Harrison primarily for use in marine chronometers to compensate for temperature-induced errors in timekeeping.

This application is still relevant in precision instruments where temperature stability is crucial.

Fire Alarms

Some fire alarms use bimetallic strips to detect heat. When a certain temperature is reached, the strip bends and triggers the alarm, alerting occupants to the presence of a fire.

Automotive Applications

Bimetallic strips are used in various automotive components, such as temperature sensors for engine management systems, where they help maintain optimal performance and prevent overheating.

Household Appliances

Common household appliances like irons, ovens, and toasters use bimetallic strips to regulate temperature.

The strip ensures the appliance maintains a consistent temperature, preventing overheating and ensuring safety.

Electrical Overcurrent Protection

In circuit breakers, bimetallic strips are used to detect overcurrent conditions. When excessive current flows through the circuit, the strip heats up, bends, and trips the breaker, cutting off the electrical supply to prevent damage.

What Happens When A Bimetallic Strip Is Heated?

When a bimetallic strip is heated, an interesting process occurs due to the different thermal expansion rates of the two metals bonded together. Here’s what happens:

Differential Expansion

Each metal in the strip has a different coefficient of thermal expansion, meaning it expands at different rates when subjected to heat.

Typically, one metal (let’s call it Metal A) has a higher coefficient of expansion than the other metal (Metal B).

Bending or Curving

As the bimetallic strip is heated, Metal A expands more than Metal B. Since these two metals are rigidly bonded, the difference in expansion rates causes the strip to bend or curve. The strip bends towards the metal with the lower coefficient of thermal expansion (Metal B).

Mechanical Movement

The bending of the strip can be harnessed to perform mechanical work. For example, in a thermostat, the bending action of the strip can open or close an electrical contact, thereby turning heating or cooling systems on or off.

Thermal Sensitivity

The degree of bending is proportional to the temperature change. This property allows the bimetallic strip to be used as a precise temperature-sensitive device in various applications.

Which Is The Principle On Which The Bimetallic Strip Works?

The bimetallic strip operates on the principle of differential thermal expansion. When two metals with different coefficients of thermal expansion are bonded together and subjected to temperature changes, they expand or contract at different rates.

This difference in expansion causes the strip to bend or curve, as one metal expands or contracts more than the other.

This bending motion, which is directly proportional to the temperature change, is harnessed for various practical applications such as temperature measurement and control, acting as a switch in devices like thermostats and thermal protectors.

What Is The Principle Of Bimetallic Expansion?

The principle of bimetallic expansion is based on the concept that different metals expand at different rates when exposed to temperature changes.

When two metals with distinct coefficients of thermal expansion are bonded together into a strip, any temperature change will cause them to expand or contract at different rates.

This differential expansion leads to the bending or curving of the strip because one metal elongates more than the other.

This bending action is utilized in various practical applications, such as in thermostats, thermal switches, and temperature gauges, to measure and respond to temperature changes efficiently.

Which Metal Expands More In A Bimetallic Strip?

In a bimetallic strip, the metal that expands more when heated is the one with the higher coefficient of thermal expansion.

Common examples of such metals include brass and copper, which typically expand more than metals like steel or Invar.

The difference in expansion rates between the two metals is what causes the bimetallic strip to bend or curve when subjected to temperature changes.

Conclusion

Bimetallic strips exemplify the elegant synergy between materials science and thermal engineering.

By leveraging the differing expansion rates of two bonded metals, these strips convert temperature changes into mechanical movement.

This principle of differential thermal expansion has led to numerous practical applications, ranging from household thermostats and appliances to industrial controls and precision instruments.

Bimetallic strips are fundamental components in many devices, ensuring reliable temperature measurement and control.

Their simplicity, reliability, and effectiveness make them a cornerstone of modern technology, continuing to play a vital role in our everyday lives and various industries.

4-20 mA Current Loop

Posted on by
Reply

The 4-20 mA current loop remains one of the most dominant types of analog output in the industry today.

In this article I will look at the history of the 4-20 mA loop, why it is widely used in industry automation, and its advantages and disadvantages.

What is a 4-20 mA current loop?

The 4-20 mA current loop especially refers to the wire connecting the sensor to a receiver that receives the 4–20 mA signal and then returns to the transmitter. 

The history of 4-20 mA current loop

At the beginning of the industry automation, most mechanical devices were controlled by a pneumatic signal; these systems were costly, bulkier, and difficult to repair. The control signal used back then was 3-15 psi.

With the huge development of electronics in the 1950s, electronic devices became cheaper, and eventually, the old pneumatic 3-15 psi systems were replaced by the analog controllers that used the 4-20 mA.

Why 4-20 and why not 0-20 mA?

Now we know that the control signal that was picked was 4-20 mA, the question I often get is why 4- 20 mA and not 0-20 mA? The simple answer is that there was a problem with the dead zero.

What is a dead zero issue?

A dead zero is when you start the lowest signal with 0mA, and the controller will not be able to differentiate if the 0mA is because the sensor detects the lowest signal value or there is an open circuit.

If you have an H2S sensor that detects 0 to 100 ppm, it will show 0 mA when there is 0 ppm of H2S, and it will also show 0 mA when there is an open circuit in the loop. This will have a huge impact on the process control.

How do you solve a dead zero issue?

The solution was simple: start with a number above zero; in the same example, if the sensor reads zero, it will send 4 mA, and if there is an open circuit, it will send a 0 mA signal. The problem is solved.

Why 4 mA?

We said above that to solve the dead zero issue, there was a need to start the value at a value greater than zero, the next question is, why 4ma and not another value? Here is the answer.

Electronic chips require at least 3mA to work

To move from mechanical controllers to electronic ones, electronic chips were introduced. Those chips require a minimum of 3 mA of current to function, so a margin of 4 mA is taken as a reference.

The 20% bias

The original control signal was 3-15 psi; 20% of 15 is 3, and 20% of 20 mA is 4 mA.

Why 20mA?

There are 3 reasons why 20 mA was picked:

The human heart can withstand up to 30 mA.

20 mA is used as the maximum because the human heart can withstand up to 30 mA of current only. so, from a safety point of view, 20 mA is chosen.

1:5 rule

The 4-20 mA was designed to replace the old 3-15 psi, and since most instruments at the time were using this control signal, there was a need to design the new signal that would follow the same pattern.

Lineality 

With the current signal being linear, it is easier to design and implement the control system using the 4-20 mA signal.

Easy to design

Most industrial transmitters are powered with 24 V, and since the signal obeys Ohm’s law, V=IR, it makes it easier to design devices that can be connected to the 4-20 mA loop.

Simple calculations

Having a signal that ranges from 4-20 mA makes it very easy to calculate the expected values. if we have a sensor that detects the 0 to 100 range, here are the estimated current values.

0-4 mA

25-8 mA

50-12 mA

75-16 mA

100-20 mA

It is that simple.

Simple conversion to 1-5V

For other elements of industry automation to interpret the signal, there is a need to convert it to a digital signal.

Most ADCs (Analog-to-Digital Converters) use voltage to convert the signal; by using the precision 250-ohm resistor, it makes it easier to convert the analog signal to a digital one by using Ohm’s law, V=IR.

Types of 4-20 mA current loop

There are 4 types of 4-20 mA current loops, where the two-wire loop version is by far the most common.

There is a three-wire 4-20 mA source, 3-wire 4-20 mA sinks, and four-wire 4-20 mA variants that are similar in their fundamental working principle.

I explain the difference between them in this article here.

Advantages of 4-20 mA current loop

Worldwide industry standard

Since it is easier to implement and design control loops with a 4-20 mA signal, it is widely used in many industrial automation industries.

Easy to connect and configure

The 4-20 mA loop is easy to design, configure, and wire; you do not need a lot of training to wire or configure it; hence, it is used in most applications.

Less sensitive to electronic noise

Electronic noise can affect the information the cables are carrying since the signal is transported as a current, which is less sensitive to electronic noises than voltage.

Fault detection using live zero

Since the signal starts at 4 mA, it is very easy to know if there is a fault in the loop; if we receive 0 mA, we know there is a fault somewhere.

You can use a simple multimeter to detect a fault

Since the loop will carry current, you can measure the current by using a simple $10 multimeter; this will reduce the diagnostic time and fault detection cost.

Disadvantages of the 4-20 loop

There are a few disadvantages to using the 4-20 mA loop; for me, these two are the main ones.

The current may introduce a magnetic field

The current may introduce magnetic fields and crosstalk to the parallel cables; this can be solved by using the twisted wire cable.

One pair of cables can only carry one process

This is huge. When you design a control loop using a 4-20 mA signal, you need to know that one loop can only have one variable, so if you have many loops, you will need more cables, and this will increase the cost of installation and eventually make the fault diagnostic more complicated.

Conclusion

We took a look at the famous 4-20 mA current loop. We looked at the history of the 4-20 mA loop, why it is widely used in industry automation, and its advantages and disadvantages.

If you have anything to add to this or a question, please leave your comment below. Thank you for reading.