Enhancing processes and improving operations with PID loop monitoring
Proportional-integral-derivative (PID) loop monitoring technology can help facilities find a solution for enhancing process control and operational stability.
Learning Objectives
- Understand the fundamental principles and components of proportional-integral-derivative (PID) loop monitoring, including how it measures and controls process variables to maintain desired setpoints.
- Learn how implementing PID loop monitoring is being leveraged in digital transformation for data-driven results.
- See a real-world application on how PID loop monitoring can address specific operational challenges and contribute to an improved plant.
PID loop monitoring insights
- Proportional-integral-derivative (PID) loop monitoring improves process efficiency by automating control adjustments and providing real-time insights, minimizing downtime and ensuring smooth, consistent operations through proactive system maintenance.
- Real-world applications of PID loop monitoring demonstrate tangible benefits, such as reducing energy use, detecting faults early, and enhancing operational performance in manufacturing, leading to cost savings.
Maintaining efficiency and reliability in manufacturing remains critical. Proportional-integral-derivative (PID) loop monitoring is a cornerstone in better understanding and managing your critical loops. Offering automated and continuous oversight of control loops, this technology provides insights that, when used properly, enhance process efficiency and reliability.
Understanding PID loop monitoring
PID loop control involves measuring process variables such as temperature, pressure, flow, level or speed within a manufacturing system and adjusting control variables such as control valves or variable frequency drives (VFDs) to guide the process variable to a setpoint. The PID controller uses three algorithms that together to adjust the output and maintain the desired setpoint (see Figure 1).
Figure 1: This is an example of a dashboard in a PID loop monitoring tool. The daily run scoring dashboard shows the travel time of each PID loop and displays its green/yellow/red performance over each day. Courtesy: Interstates
Some of the key performance indicators (KPIs) you may monitor in a PID loop tool include cycle time, cycle response, oscillation magnitude, oscillation percent, and settling time. David King, analytics delivery leader at Interstates, compares PID loop monitoring to a car’s cruise control: “You want to accelerate to your target speed quickly but without overshooting or creating oscillation in your car’s speed.”
Much like cruise control, which involves the gas pedal, car speed and target speed, this solution has three parts: A sensor, a controller and an actuator. These elements work in tandem to regulate system performance and ensure operational stability (see Figure 2).
Figure 2: PID loop monitoring gathers data on important key performance indicators for operations. Those include cycle time, cycle response time, setting time, oscillation magnitude and/or oscillation percent. Each of these metrics can be seen in one chart. Courtesy: Interstates
While loops work well right after tuning, the performance can degrade. Traditionally, PID loop maintenance has been performed on an as-needed basis, often when process engineers identify performance issues. Incorporating a monitoring tool can provide real-time insights into both short-term events, such as spikes outside the set boundaries and longer-term trends such as increased oscillations or a gradual increase in fault frequency.
The tool can inform proactive maintenance activities, including the replacement of worn components, adjustments to mechanisms or modifications to process schedules, ensuring optimal performance and preventing unexpected downtime.
Three benefits of PID loop monitoring at a facility
PID loop monitoring, once installed, continuously runs, capturing data and showing performance history to improve loop performance. Here are a few key benefits:
1. Operational efficiency: The data and insights from a monitoring tool can inform tuning operations, helping to maintain maximum efficiency. This proactive approach improves product quality, enhances safety and increases output.
2. Cost savings: Carbon Trust reports that properly tuned control loops can reduce energy consumption by 5 to 15%, increase throughput by 2 to 5%, increase yield by 5 to 10% and improve quality by 25 to 50%. It all begins with knowing when to tune which loops.
3. Fault detection: Monitoring loops allow for early detection and diagnosis of system faults, malfunctions or disturbances. This allows personnel to take corrective actions and prevent maintenance issues (see Figure 3).
Figure 3: Users can set up automatic alerts using the monitoring tool. For example, these can be generated when loops drift too far from the set point. Here is an example of that automated report. Courtesy: Interstates
Improving bottle-filling operations with PID loop monitoring
To illustrate the practical benefits of PID loop monitoring, consider a recent project with a consumer-packaged goods client. The client faced persistent challenges with their bottle-filling operations, particularly in maintaining consistent product dispensation. The lack of visibility into process variables made troubleshooting difficult and optimization almost impossible.
Implementing a PID loop monitoring tool that enhanced monitoring capabilities and operational efficiency. Here’s how:
1. Virtual machine and software deployment: A virtual machine (VM) was set up to run the PID loop monitoring software, collecting real-time process data from a programmable logic controller (PLC). Alerts were generated based on pre-set analytical baselines, providing immediate feedback on process performance.
2. Targeted coverage: The solution was applied to one area of the plant, covering seven packing lines. This focused approach allowed for detailed monitoring and control, addressing the most critical issues.
3. Real-time insights: Process engineers and maintenance technicians received real-time alerts about PID loop performance, including contextual data such as pump speed, frequency and setpoints. This enabled quick, informed decision-making and improved overall process efficiency.
Data shows pressure level inefficiencies
Implementing PID loop monitoring yielded several tangible benefits for the client, including enhanced visibility into critical process variables. One variable was the pressure variation in tanks, which is crucial for maintaining product quality.
Through the data provided by the monitoring dashboard and reports, the client observed minimal pump speed variations when the product tanks were full due to stable pressure levels. However, as the tanks dispensed the product, there were higher variations in pump speed, indicating the need for adjustments based on tank levels.
“The PID loop monitoring tool has enabled us to historically analyze instances where we have had issues filling and allowed us to visualize it in a way that is very similar to our PLC trend. This enables us to solve issues without having to be on the line,” King said.
These insights allowed the client to make precise, data-driven adjustments, ensuring more consistency in the bottle-filling process.
Eight ways to leverage PID loop monitoring for digital transformation
Leveraging PID monitoring can enhance operational efficiency, data-driven decision-making and overall competitiveness (see Figure 4). It is more than just a tool for immediate process improvement; it’s also essential for broader digital transformation. There are eight ways it can be strategically integrated:
Figure 4: For a quick and easy way to view a summary of PID loop data, users can use the PID loop user dashboard. This displays events and loop performance data from the last seven days. Courtesy: Interstates
1. Data integration and analytics: Integrate the control loop data with other operational data sources to create a comprehensive view of plant operations. Utilize advanced analytics and machine learning to analyze this data, identifying patterns and anomalies that human operators might miss. This approach enables predictive maintenance, real-time optimization, and enhanced quality control, transforming raw data into actionable insights.
2. Improved decision-making: With real-time data from PID control loops, decision-makers have nearly live information from the production floor. This facilitates quicker, more informed decisions rather than relying on outdated reports or guesses. For instance, adjustments in the production process can be made in response to feedback from the monitoring system.
3. Automated adjustments and control: Use the insights gained from monitoring to automate control adjustments, minimizing the need for manual intervention. This not only speeds up response times but also ensures more consistent and optimal settings that adhere to predefined quality and efficiency standards. Automation in this context reduces human error and enhances operational reliability.
4. Enhanced quality control: Monitoring directly impacts product quality because it shows whether manufacturing processes remain within set parameters critical to product specifications. Consistency in operation leads to less variation in output, ensuring all products meet quality standards, which is vital for customer satisfaction and compliance.
5. Energy efficiency and cost reduction: Maintaining optimal control loop performance allows manufacturers to achieve significant energy savings. Well-tuned PID loops operate more efficiently, reducing waste and excessive use of raw materials and energy. This translates into lower operational costs and a reduced environmental footprint.
6. Training and skill development: Digital tools that monitor and analyze PID control loops can also be used for training new operators and engineers. Simulations and historical data help in understanding how different settings affect the system, enhancing the skill set of the workforce and preparing them for a more digitalized industrial environment.
7. Scalability and flexibility: As businesses grow or diversify, PID control loop monitoring systems can scale accordingly. They can be integrated into new lines or adapted to new products, making the digital transformation strategy flexible and adaptable to future needs and technologies.
8. Regulatory compliance and reporting: Automated data collection and analysis facilitated through real-time process monitoring ensure that companies can comply with regulatory requirements. Detailed records of process conditions and adjustments aid in auditing and reporting processes, which is essential for industries with strict regulatory oversight (see Figure 5).
Figure 5: Users can see trends in PID performance with additional context from the machine’s key indicators. Courtesy: Interstates
PID loop benefits
PID loop monitoring is a transformative technology that automates the oversight of control loops, informing actions that can benefit process efficiency, reliability and maintenance. Integrating advanced analytics and remote access capabilities empowers manufacturers to optimize operations, save energy and reduce environmental impact. As the real-world example demonstrates, this technology can address persistent operational challenges and enhance overall production processes. Embracing PID loop monitoring is a strategic step towards achieving sustainable efficiency improvements in industrial automation.
By understanding and implementing PID loop monitoring, facilities can boost their production capabilities and ensure a smoother, more efficient operational flow.
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