ISA CAP Foundational Concepts & Principles 2

Question 1

Which ISA standard defines the functional requirements for programmable electronic systems used in safety instrumented systems?

Accepted Answer

ISA-84.00.01

Answer

ISA-84.00.01 (equivalent to IEC 61511) defines requirements for safety instrumented systems (SIS) in the process industry.

Question 2

In process control, what does the term 'dead time' refer to?

Accepted Answer

The delay between a change in process input and the first observable change in process output

Answer

Dead time (also called transport delay) is the elapsed time between a change in a process variable input and the first detectable response in the output.

Question 3

What is the primary purpose of a feedforward control strategy?

Accepted Answer

To compensate for disturbances before they affect the controlled variable

Answer

Feedforward control measures a disturbance and applies a corrective action before the disturbance can affect the controlled variable, unlike feedback which reacts after the fact.

Question 4

The 'gain margin' of a control loop is best described as:

Accepted Answer

How much the loop gain can increase before the system becomes unstable

Answer

Gain margin is the factor by which the open-loop gain can be increased at the phase crossover frequency before the closed-loop system reaches the verge of instability.

Question 5

Which of the following best describes a 'split-range' control configuration?

Accepted Answer

One controller output driving two or more final control elements in sequence

Answer

In split-range control, a single controller output is divided across two or more final control elements (e.g., valves), each responding to a different portion of the output signal range.

(ISA CAP) ISA Certified Automation Professional Practice Test

(ISA CAP) ISA Certified Automation Professional Practice Test

ISA CAP Foundational Concepts & Principles 2