Three new tips for revitalizing control systems
Three control system improvements: Heed these open-loop PID tuning tips, create a 30% throughput increase and optimize control system alarms. These are among leading tips in Control Engineering July/August edition.
Learning Objectives
- Understand three PID open-loop tuning tips and two limits.
- Visualize automation software that can create a 30% output gain, better decisions.
- Address alarm system challenges in SCADA systems with this advice.
Three of many favorite excerpts follow from this Control Engineering July/August issue can help improve effectiveness of control systems this summer.
Three open-loop tuning tips, two limits
Ed Bullerdiek, retired process control engineer offers PID tuning with three open-loop tuning tips and two limitations. Three open-loop tuning tips are:
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Make multiple steps when performing the open loop test (minimum of three).
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The step sizes should be different.
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The step sizes should be made in opposite directions. This is necessary to see if the valve is working. (A cascade master may not require multiple steps as valve performance should not be a problem.)
Two open-loop tuning limitations are:
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Slow control loops may be difficult to test. External disturbances may make it difficult to guess an ultimate gain and curve inflection point, which will make it impossible to calculate loop-tuning constants.
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Bad valves will warp the results. Estimated ΔPV can be wildly inaccurate, especially with small step sizes. Deadtime may also appear variable based on valve response. As a matter of good practice before tuning an existing control loop, you should check the loop for valve problems and other non-loop tuning related problems.
See practical examples and graphics from Bullerdiek starting on Page 25, “PID spotlight, part 7: Open-loop tuning of a self-limiting process.”
Automation software: 30% output gain, better decisions
Rob McGreevy, chief product officer at Aveva, explains how a centralized, scalable data infrastructure creates closer understanding and real-time collaboration. Within a connected industrial ecosystem, everyone can make better decisions, business operations become more efficient, resource use is optimized and waste minimized.
He continued with a quantified example of benefits. “By modeling the impact of changes such as higher temperatures or water use, Pet Nutrition can adjust manufacturing processes in real time to keep quality on track. The result? Process-to-product output is up 30% while waste is down.” Get more advice from McGreevy on Page 17, “From ecosystems and AI to the industrial metaverse.”
Alarming challenges with alarm systems? Here’s how to improve
System integrator Jason Israelsen, PE, control engineer for APCO Inc., examines alarm-system health in supervisory control and data acquisition systems (SCADA). Four-step process identifies, addresses and maintains the health of an alarm system with analysis, review, acting and repeating. Israelsen provides more details and examples start on Page 19, “Improve SCADA systems by analyzing alarm system health.”
Think again about how to share your summer wisdom with Control Engineering peers.
https://www.controleng.com/connect/how-to-contribute/
Mark T. Hoske is editor-in-chief, Control Engineering, WTWH Media, mhoske@wtwhmedia.com.
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www.controleng.com/magazine
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