Ask The Experts

Get Answers to Your Process Control Questions Here

"Ask The Experts" is moderated on ControlGlobal.com by noted process control authority and CONTROL Columnist Bela Liptak. Liptak either answers the questions himself, or brings in one or more experts from his cadre of co-authors that worked with him on the Instrument Engineers' Handbook, Fourth Edition. Save yourself the hefty consulting fees by getting the answers to your questions here.

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TOPICS PREVIOUSLY COVERED

• Deaerator Level Control
• Protecting Blast Furnace Pressure Transmitters from Plugging
• D/P Impulse Lines; Chinese Solar Tech
• PLC Redundancy- How Much is Enough?
• Vortex Flowmeter Problems
• Valves vs. VFDs; Digital Level Transmitters
• Orifice Rangeability; Non-Renewable Energy Sources
• Weather, Plus Compensation, Transmission, Standardization
• Measurement of Drift, Stability, Offset, Bias
• Two-Way PD Flow Measurement of LPG
• More on BP Oil Spill; Restriction Orifice Sizing
• Control Valve Simulation in the Age of the Black Box
• Microprocessor Control of Remote Pipeline Sites
• Process Control in Archeology and Meteorology
• Can Process Control Prevent Oil Well Blowouts?
• Nuclear Waste Sludge Management; MPC References
• Getting Respect and Preventive Valve Maintenance
• Temperature Control with Slow Boilers
• Response to Control Mode Switching
• Gas Blending Control; Pipe Schedule and Control Valve Size
• A Gathering of Eagles: Ask the Experts Special Edition
• Model-Based Control of Fast Processes
• Safe Valve Positions
• Liquid Hydrogen Level Transmitters; Power Supplies
• Steam Quality Measurement; Automation Levels
• Aviation Safety; Variable Control Valve Failure
• Flowmeter Selection
• Piezometers for Flow Measurement; Level Gauges
• Vortex Flowmeters; Galvanic Thermowell Corrosion
• Flowmeters, Multi-Lingual Keyboards, DCS/PLC Websites
• Solar Power Plants, Orifice Vent Holes, District Heating
• Magnetic Flowmeters, Nuclear Plants
• Calibrating Injection Molding Machines, Compressor Control
• Gas Blanketing Controls and How to Contribute to IEH v.5
• Three-Mile Island, Preventing Boiler Blowups and More
• Orifice Rangeabilty; Bubblers for Difficult Service
• Steam Heat and More on Calibration
• TV Reports, Heating Value of Natural Gas, PID Outputs
• Continuous Level Measurement; Noise Filters
• How to Measure pH Inside a Tank; Increasing Scan Times
• Cavitation in Control Valves
• Split-Ranging Multiple Valves
• D/P Cell Installation, Elevation; Isolation Fuses in Is Circuits
• Does Valve Size Matter? Ethernet or Modbus?
• Open Loop Tuning and Process Control en Español
• Difficult Level Measurements
• Solar Generators; Control Valve Boosters
• D/P Cell Settings, Plus Good Books
• Detecting Bunker C Oil Mass Flow
• Aluminum anodizing temperature control
• Regulating inlet fluid temperature
• Measuring flare gas; Controller set points
• Ink control, steam drums, smart positioners
• Features and capabilities of hybrid controllers
• Failing safely with shutdown systems
• Getting loopy with control loops
• So much to learn, so little time
• We can't believe our vortex shedding flowmeter
• Where are the best opportunities in the field of process control?
• Measurement problems on a high level
• Books and online courses recommended for continued education
• Valve-position control with an external reset feedback
• Reactor level measurement
• Bumpless switching of most open valves

 

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HOW DO I . . .
We've started a series of informative process control "How To" articles we hope will be of interest to you at ControlGlobal.com. These articles are short, informative, and without relevance to specific products. They are written for a general understanding of process control techniques, applications and solutions.  

• How do I adjust for DO₂
  Flexibility is what you need when it comes to controlling fermentation. This abbreviated description (full version is AN304) focuses on applying Mantra's advanced process control solution for dissolved oxygen.
• How do I tune cascade loops
  Tuning a cascade loop is simple, as long as the concepts of the cascade loop are understood. In this installment of "How Do I . . ." we take a look at a common cascade loop application.
• How do I select an ultrasonic system
  In water and wastewater plants around the world, ultrasonic is the level and fl ow technology of choice, and for many good reasons.

 

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About the Moderator

 

	Ask The Experts
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Bela Liptak, PE, is a process control consultant and editor of the "Instrument Engineers' Handbook, Fourth Edition." He is seeking new co-authors for the forthcoming edition of that multi-volume work and can be reached at liptakbela@aol.com.