Why is control technology used? To keep a process (such as a temperature or speed, pressure or position) running continuously without operator manually changing it, as the process continues. It does this by measuring the process, comparing that reading to a set value (set-ramp) and automatically adjusting the process to comply with the set value. Consistency and efficiency, safety, speed and visibility are the payoffs.
What Control Technology Does
Control systems consist of four elements-sensors, actuators, controllers, and human machine interface (HMI) and Management software. The basic one is the control loop consisting of a sensor, controller and control element.
There are 2 primary designs. Closed-loop or feedback control systems are systems where the output (actuator) signal is continuously compared with a set desired (reference) value to see if there is any difference and then using this difference to control the processes (actuator) to stay stable. The idea of the open loop is that this check is not done, for example a timer might not confirm the result. The closed loop approach is the main source of value in control technology.
The need for Control technology in Industry, Buildings and vehicles?
You’ll find it breaks down to 5 payoffs. These are each directly related to a tangible method of measuring results.
| Payoff | Inspired by: How control delivers it | How to measure it |
| Consistency | The same logic operates each and every time, hence the output is less variable. | The proportion of defective items in a sample, the difference from shift to shift |
| Efficiency | Precise control is an application of the energy and material just required for the job. | This is expressed in terms of energy per unit and “scrap rate”. |
| Safety | Limits and interlocks will respond more quickly than a human can. | Incidents, alarm response time |
| Speed | Corrects within fractions of a second using actuators | Cycle time, throughput |
| Visibility | Data generated by sensors can be trended and audited | Downtime is addressed in terms of audit findings. |
The first three have published overviews. According to the first description, automated control systems make it possible to achieve all of the above: increase efficiency by decreasing manual operations, make things more consistent by eliminating quality deviations and fluctuations and provide realtime monitoring for quicker adjustments. That a general automation summary is added, shares the fact that Automation is used to CONSAVE LABOUR, ENERGY, MATERIALS and IMPROVE QUALITY.
Your local school communities are the places where It’s Working
- Industrial automation: Control systems monitor and control production processes, managing machinery, assembly lines and industrial robots for smooth, precise operation.
- Buildings: Control systems – control lighting, heating, ventilation & air conditioning (HVAC).
- Everyday devices: A simple case of on/off control for a heating or cooling load is a basic electromechanical thermostat.
The shape remains the same in any location. A value is required to be maintained within bounds, the conditions are constantly changing and the adjustment is impractical, expensive or dangerous.
Control Ladder: Match the Control to the Job (Original Framework)
Advanced control is not required for all processes. Always use the lowest (easiest) rung to ensure accuracy and safety.
| Rung | Approach | Typical use |
| 1 | Manual adjustment | Rare, low-risk tasks |
| 2 | Timer (open loop) | Fixed-duration cycles |
| 3 | On/off control | Switches for heating and cooling control, buoys, switches for tanks |
| 4 | PID feedback control | Temperature / speed control or pressure control without any variation. |
| 5 | Supervisory Control (PLC / DCS) | Multi-looping the coordination for one plant |
Only use a step up if a problem can be detected in the step below, e.g., overshoot, rework or operator workload. Each ohm increase costs, tuning modes and tuning failures.
Newer Directions
Control technology is shifting towards connection and remote operation. effective-control.net indicates that IoT-based control systems facilitate remote monitoring and control of the processes, while cloud-based platforms are increasing control systems’ accessibility and scalability. Automation overviews additionally consist of the incorporation of AI and machine learning right into automation systems.
Limits and Risks
trade-offs of control technology that must be planned for exist:
- Oscillation and overshoot of the equipment is a result of poor tuning and can lead to increased wear.
- Calibration and redundancy are important to prevent making confident incorrect decisions due to bad sensor data.
- Network segregation, access control and patching are part of the design as the connected systems also add to the attack surface.
- Monitoring trends (as well as alarms) can allow quiet compensation to mask a degraded part until the loop ceases to be able to handle it.
ControlPaybackChecklist is a Linkable Asset to control the Payback Checklist.
- A variable cannot exceed or surpass a particular range, otherwise it becomes poor in quality or unsafe.
- Changing conditions may be quicker than the ability to adjust.
- Temperatures outside the operating range; leads to waste, damage or risk.
- Measurement of the variable is reliable and some action can be taken
- I have a defect baseline, and energy usage/outage baseline
- I am familiar with the persons responsible for the calibration, maintenance and security of the system.
- I selected the least of the steps on the ladder that is a solution to the problem.
- I will re-measure after commissioning, so you can be sure of your payoff
Guest Post Angles
The following topics are applicable for engineering, manufacturing, and facilities and smart-building publications:
- Open Loop vs Closed Loop for Home Appliances: A Smart Explainer.
- Retrofit story: Manual replacing by PID one process.
- Security for operational technology: Not disrupting production.
Begin with the loop that results in the greatest amount of rework
Identify process variable that most often varies or requires operator attention. For one week measure it and record cost of drift for scrap, energy or labor. That’s the number if you are still wondering why is Control technology used in your given environment? If you choose a loop that you will be happy with, before taking the necessary step of scaling up, you will see the payout.
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