ISA CAP Technology & Tools 2

Question 1

Which communication protocol is most commonly used for HART field devices to transmit digital signals over a 4–20 mA analog loop?

Accepted Answer

Highway Addressable Remote Transducer (HART)

Answer

HART uses FSK modulation to superimpose digital signals on the 4–20 mA analog current loop, enabling two-way communication with field devices.

Question 2

In a Distributed Control System (DCS), what is the primary function of the historian server?

Accepted Answer

Store time-stamped process data for trend analysis and reporting

Answer

The historian server collects and archives time-stamped process data, enabling long-term trend analysis, reporting, and compliance documentation.

Question 3

Which fieldbus technology is commonly used in process automation and provides an intrinsically safe option with data rates up to 31.25 kbps on the H1 segment?

Accepted Answer

Foundation Fieldbus H1

Answer

Foundation Fieldbus H1 operates at 31.25 kbps and supports intrinsic safety, making it suitable for hazardous area installations in process plants.

Question 4

A SIL 2 Safety Instrumented Function (SIF) requires a Probability of Failure on Demand (PFD) in which range?

Accepted Answer

≥10⁻³ to <10⁻²

Answer

IEC 61511 defines SIL 2 as a PFD range of ≥10⁻³ to <10⁻², corresponding to a risk reduction factor of 100 to 1,000.

Question 5

What is the primary advantage of using OPC UA over the original OPC DA standard in industrial automation?

Accepted Answer

OPC UA is platform-independent and provides built-in security

Answer

OPC UA is platform-independent, runs on any OS, and includes built-in security features such as encryption and authentication, unlike the COM/DCOM-based OPC DA.

(ISA CAP) ISA Certified Automation Professional Practice Test

(ISA CAP) ISA Certified Automation Professional Practice Test

ISA CAP Technology & Tools 2