Control System Design & Architecture Flashcards
7 cards from real CCST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Control System Design & Architecture flashcards as text
In a distributed control system (DCS), what is the primary role of the historian server?
Answer: Store and retrieve time-stamped process data for trend analysis
The historian server archives time-stamped process variables, enabling long-term trend analysis, reporting, and troubleshooting.
Which control architecture places intelligence directly at the field device level, reducing reliance on a central controller?
Answer: Fieldbus-based control
Fieldbus-based control (e.g., FOUNDATION Fieldbus) allows function blocks to execute directly within smart field devices, decentralizing control.
A control system designer specifies a 1oo2 (one-out-of-two) voting architecture for a safety shutdown. What does this mean?
Answer: Either one of two sensors can initiate a trip
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.
When designing a loop for cascade control, which statement about the inner (secondary) loop is correct?
Answer: It must be tuned to respond faster than the outer (primary) loop
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.
What is the purpose of a marshalling cabinet in a large DCS installation?
Answer: To terminate and cross-connect field wiring before routing to I/O cards
Marshalling cabinets aggregate and cross-connect field instrument cables, providing a flexible wiring junction point before signals reach the DCS I/O subsystem.
In an ISA-95 enterprise control hierarchy, which level is responsible for production scheduling and resource management?
Answer: Level 3 — Manufacturing operations management (MOM)
Level 3 (MOM/MES) handles production scheduling, batch management, quality, and maintenance coordination within the plant.
A control engineer wants to prevent integrator windup in a PID controller when the output is saturated. Which design feature addresses this?
Answer: Anti-windup reset (back-calculation or clamping)
Anti-windup schemes limit or reset the integral term when the controller output is at its saturation limit, preventing excessive overshoot when the output re-enters normal range.