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3 weeks ago | 
emersonautomationexperts.com | Jim Cahill |Greg McMillan
The surge controller setpoint should be offset to the right of the surge curve on the compressor map so that the surge setpoint follows the shape of the surge curve, enabling the margin to be optimized to be on the longitudinal axis of the efficiency ellipses. The margin size depends on the speed of the automation system, the tuning of the surge controller, and the disturbance speed.
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1 month ago | 
emersonautomationexperts.com | Jim Cahill |Greg McMillan
If you’re an engineer working in a process with centrifugal or axial compressors, you’re probably well-versed in the topic of compressor surge. If not, I came across a nice post from several years ago on the Mechanical Engineering Site, Centrifugal Compressor Surge Basics, Mechanism. Here is how the author defines surge.
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Jan 31, 2025 | 
emersonautomationexperts.com | Jim Cahill |Greg McMillan
The Smith predictor control algorithm goes back to the 1950s. Its purpose and history are described in Wikipedia. The Smith predictor (invented by O. J. M. Smith in 1957) is a type of predictive controller designed to control systems with a significant feedback time delay. But is it the best approach to handle feedback time delay? A fascinating ControlGlobal.com article, Face-off: Smith Predictor vs. deadtime compensated PID, highlights the possibility of a better approach.
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Jan 15, 2025 | 
controlglobal.com | Greg McMillan
Control valves are used to manipulate flows in most control loops. Control valve selection and specification is critical to achieving good control loop and process performance. Here’s a look at some of the essential aspects of the best control valves. Let’s start with what I think is the missing knowledge that’s important for the control valve’s dynamic response.
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Dec 6, 2024 | 
controlglobal.com | Greg McMillan
Greg: There’s been a lot of buzz in the industry regarding artificial intelligence (AI) and machine learning (ML). Vendors claim their tools can transform operations and leap tall buildings in a single bound. So, how do we get past the hype and unlock the real value for industrial plants? Julie Smith, group manager for DuPont’s Engineering Technology Center and its global automation and process control leader, is once again here to discuss these two trends.
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Nov 7, 2024 | 
controlglobal.com | Greg McMillan
Greg: I’ve previously advocated using dynamic simulation to drive process control improvements and train operators. But there’s another, sometimes overlooked, use case for getting the most out of control system migration projects. Julie Smith, DuPont group manager and global automation and process control leader at the Engineering Technology Center, offers insights gained over many decades. Julie, has your team seen value in this use case?
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Oct 31, 2024 | 
controlglobal.com | Greg McMillan
Greg: In September, I talked with Marsha Wisely, president of PlantWise Industrial Consulting, about some of the value of process simulation. In that article, we explained that you don't always have to go with a complex or high-fidelity model to get value. However, your process simulator must match production, so any testing, training and optimization of the system is relevant to your current production.
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Oct 30, 2024 | 
emersonautomationexperts.com | Jim Cahill |Greg McMillan
Greg McMillan presented pH Measurement Best Practices at the recent Mary Kay O’Connor Safety & Risk Conference as part of the 79th Annual Instrumentation and Automation Symposium For the Process Industries. Here is the abstract from the pH Measurement Best Practices paper that Greg also submitted. pH measurement has the greatest sensitivity and rangeability by far of any ion composition measurement. However, there are many challenges in terms of the installed accuracy and life expectancy.
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Oct 18, 2024 | 
emersonautomationexperts.com | Jim Cahill |Greg McMillan
You only have to visit Greg McMillan’s author page here on the blog to see his massive contributions to our automation profession. I came across a recently published ControlGlobal.com article, Greg McMillan profiled in Who’s Who. This is well-deserved recognition for Greg. ControlGlobal.com’s Jim Montague opens the article by highlighting this accomplishment. Marquis Who’s Who reported Aug.
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Sep 10, 2024 | 
controlglobal.com | Greg McMillan
Greg: Real-time process simulation is a powerful tool. From engineering testing to operator training, having a virtual plant to test and train helps reduce risks in manufacturing facilities. Originally designed for site acceptance testing (SAT), operator training systems (OTS) and process control improvement (PCI), simulators focus on automation system details, such as inputs, outputs and dynamic relationships, all of which affect control system and operator performance.
