Process Control: Improving Plant Performance

| Marica Pohl

Process Control

Loop Monitoring for Operational Intelligence

Many manufacturing plants across the Northeast have been researching new tools or resources that could aid their productivity and profitability efforts. For process control users, your research might involve consideration of software, analytics, ability to track multiple process variables, ability to monitor variables against established norms, and more.

Control loop performance monitoring software is an option for process control applications. It can be a solid investment if you and your team are looking to improve your facility’s operational intelligence. What are the benefits?

  1. It helps users proactively detect production issues
  2. It equips users with valuable insight and actionable information

Both are absolutely required for effective process control. So what is “control loop performance monitoring software”? This post will provide an introductory explanation.

A Closer Look at Control Loops

OK. For any process that we are trying to control, there is a variable. We want the variable to meet the desired setpoint. Things in our system might be moving and filling and dispensing all at once, representing ups and downs in the variable. The setpoint is our target, but the target is moving. Essentially, our Control Loop will take these ups and downs into account and constantly adjust for the desired setpoint!

The Control Loop will include things that measure, a typical example will be process sensors. As these sensors measure something, say, the level of fluid in a tank, they feedback to the Process Control devices and can intelligently say whether to increase or decrease the rate of fill into this tank.

The rest of this post assumes you have an interest in these technical points of process control. The deep and dark parts of Control Loop management involve differential equations and might be a bit too complex for this blog post. For those that might be interested, I recommend Control Station’s blog. This offers medium length articles on topics such as noise, controller tuning, and root-cause analysis. Excellent further reading.

Improve Uptime, Improve Profitability

Do you need help identifying performance issues before they lead to costly downtime? Unplanned downtime can be a real setback. Not only does it directly impact the company bottom line profitability – it can be a hassle and have cascading effects. Do you spend too much time dealing with costly downtime? Would you like to spend less?

Process Control Loop

A screenshot of control loop performance monitoring software from Control Station Inc. View the larger resolution version of this image here.

Control loop performance monitoring can leverage existing historical process data to uncover details that might lead to equipment failure. Software exists that can provide a warning regarding negative trends like valves that are being overworked due to Stiction. When you take proactive steps to avoid equipment failure, you are avoiding costly downtime. It’s probably not possible to ever 100% eliminate unplanned downtime (I guess that’s why we still call it “unplanned”). But it is possible to take steps closer towards that ideal. Each step you take is an investment that will continue showing dividends down the road. If you need help identifying performance issues, consider control loop performance monitoring (CLPM) software.

CLPM: Leverage Your Existing Historical Process Data

Identifying performance issues and isolating their root-causes can be challenging. Whether you need information for the weekly status meeting or you need information prior to a shift change – you need something customizable and in tune with your schedule.

Your greatest asset for root cause analysis is your existing data. The ability to see how your plant runs, where it’s running at optimum efficiency, and where it might be sub-optimal is a powerful tool. CLPM software like PlantESP from Control Station can provide forensic analysis of process data. It also includes a library of pre-configured reports for ease of use. Whether you’re a Plant Manager, Process Engineer, E&I Tech, or Console Operator, reports are designed to supply just the right information that you need and they can help you jumpstart your efforts by collecting and using data that already exists.

CLPM: Negative Trend Warnings

AKA “Alerts”. Every automated factory has a few “troublemakers”. Production environments are complex and inherently dynamic. Successful process control should maintain a constant watch for variations and troublemakers so you can respond promptly.

Process Control PriorityVue

A screenshot of control loop performance monitoring software from Control Station Inc. View the larger resolution version of this image here.

Example: a key loop that’s degraded steadily over the past month. Not quick enough to be red hot, but certainly not optimal.

Solution: CLPM software like PlantESP tracks the degree of change exhibited by each PID control loop within your facility. Those that exhibit the most change over a span of 1-day, 7-days, and 30-days are highlighted and the amount of change for each duration is displayed on a loop-by-loop basis.

When you are aware and informed of changes, you can direct resources effectively and efficiently.

Ongoing Process Improvement Efforts

For many process and manufacturing plants, a cross-functional team will work to tackle manageable improvement goals. Your team might involve OT, IT, production control, equipment superintendents, management, and process control engineers. You want a software solution that works for all of these varied stakeholders and gives the team actionable information to execute improvements.