CCST Control System Design & Architecture 2

Question 1

In a distributed control system (DCS), what is the primary role of the historian server?

Accepted Answer

Store and retrieve time-stamped process data for trend analysis

Answer

The historian server archives time-stamped process variables, enabling long-term trend analysis, reporting, and troubleshooting.

Question 2

Which control architecture places intelligence directly at the field device level, reducing reliance on a central controller?

Accepted Answer

Fieldbus-based control

Answer

Fieldbus-based control (e.g., FOUNDATION Fieldbus) allows function blocks to execute directly within smart field devices, decentralizing control.

Question 3

A control system designer specifies a 1oo2 (one-out-of-two) voting architecture for a safety shutdown. What does this mean?

Accepted Answer

Either one of two sensors can initiate a trip

Answer

In a 1oo2 architecture, a trip occurs if either of the two sensors detects a hazardous condition, maximizing availability but potentially reducing spurious-trip resistance.

Question 4

When designing a loop for cascade control, which statement about the inner (secondary) loop is correct?

Accepted Answer

It must be tuned to respond faster than the outer (primary) loop

Answer

The inner loop must be tuned to respond 3–10× faster than the outer loop so it can correct disturbances before they affect the primary variable.

Question 5

What is the purpose of a marshalling cabinet in a large DCS installation?

Accepted Answer

To terminate and cross-connect field wiring before routing to I/O cards

Answer

Marshalling cabinets aggregate and cross-connect field instrument cables, providing a flexible wiring junction point before signals reach the DCS I/O subsystem.

(CCST) Certified Control Systems Technician Practice Test

(CCST) Certified Control Systems Technician Practice Test

CCST Control System Design & Architecture 2