August 2007

Documenting skills is value-add

ISA certification provides an objective, third-party assessment, and confirmation of a person's skills. It gives manufacturing and factory staff the opportunity to differentiate themselves from their peers and gain recognition. InTech covers three certification areas in its monthly Certification department.

ISA Certified Automation Professional (CAP) program

Certified Automation Professionals (CAPs) are responsible for the direction, design, and deployment of systems and equipment for manufacturing and control systems.

The following question comes from the CAP study guide, Performance Domain II, Definition: Identify customer requirements and complete high-level analysis of the best way to meet those requirements

CAP question

What is required to find the MOST efficient operating points that are highly dependent on complex shifting process conditions, such as equipment fouling?

A. Real-time optimization with a detailed process model
B. Tactical schedulers with business economics
C. Linear programs with detailed process economics
D. Model predictive controls with a constraint pusher

CAP answer

The correct answer is A, real-time optimization with a detailed process model. 
 
Real-time optimization uses a reconciled high fidelity process model with the equipment details, such as heat transfer coefficients and physical properties of the components.
 
Tactical schedulers do not have process knowledge built in and may request operating points that are not achievable or advisable based on equipment and process constraints.
 
A linear program assumes fixed economic relationships and does not deal with stationary behavior shifts and nonlinear process behavior. 

A model predictive control with a constraint pusher is only able to do a simple maximization on minimization of a process variable such as feed flow.

ISA Certified Control Systems Technician (CCST) program

Certified Control System Technicians (CCSTs) calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables.

This question comes from the Level I study guide, Domain 3, Troubleshooting. Level I represents a professional who has a five-year total of education, training, and/or experience.

CCST question

Which meter does not use an obstruction?

A. Head meter
B. Magnetic flowmeter
C. Open channel meter 
D. Turbine meter

CCST answer

A magnetic flowmeter is a volumetric flowmeter, which does not have any moving parts and is ideal for wastewater applications or any dirty liquid, which is conductive or water based. Magnetic flowmeters will generally not work with hydrocarbons.

The operation of a magnetic flowmeter rests upon Faraday's Law, which states the voltage induced across any conductor as it moves at right angles through a magnetic field is proportional to the velocity of that conductor.

The fluid must be electrically conductive for the Faraday principle to apply.

The other meters in this list leverage some kind of wheel or obstacle that creates a pressure differential from which one ascertains a flow measurement.

The correct answer is B.

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ISA Certified Industrial Maintenance Mechanic (CIMM) program

Certified Industrial Maintenance Mechanics (CIMMs) are responsible for preventive, predictive, and corrective maintenance. They are multi-skilled individuals whose expertise is primarily mechanical in nature as opposed to instrumentation or electrical.

CIMMs have a minimum of five years of relevant work experience in the maintenance mechanic field or three years experience and a two-year associate degree in maintenance or a related field. This question is from Performance Domain III: Troubleshooting and Analysis.

CIMM question

After disassembling a pump, you find nothing wrong with the bearings on the shaft. What is the MOST appropriate next step?

A. Follow policy, and report the discrepancy to the management.
B. Follow policy, and replace all bearings.
C. Check the manufacture's manual for information on the life of the bearings.
D. Continue with the repair, and document the bearings will need to be replaced in the future.

CIMM answer

The correct answer is B, follow policy, and replace all bearings.

The failure rate of a used bearing is greater than the failure rate of a new bearing. Manufacturers imply the policy, "Never reuse a bearing."

Reference: ITT Industries; Gould Pump Manual; Seneca Falls, N.Y.

Nicholas Sheble (nsheble@isa.org) writes and edits the Certification department.