BOC BOC Building Automation and Controls 1 — Questions and Answers
Question 1: What does BAS stand for in building operations?
- Building Audit System
- Building Automation System (Correct answer)
- Boiler Activation Sequence
- Building Assessment Standard
Correct answer: Building Automation System
BAS stands for Building Automation System, which integrates HVAC, lighting, security, and other building systems under centralized monitoring and control.
Question 2: In a BAS, what does a DDC controller stand for?
- Direct Digital Control (Correct answer)
- Dual Device Controller
- Distributed Data Command
- Dynamic Demand Circuit
Correct answer: Direct Digital Control
DDC stands for Direct Digital Control, where a microprocessor-based controller reads sensor inputs, executes control logic, and drives outputs to regulate building systems.
Question 3: What is the role of a sensor's 'setpoint' in a BAS control loop?
- The maximum voltage the sensor can handle
- The desired target value the control system works to achieve and maintain (Correct answer)
- The calibration offset applied to raw sensor data
- The frequency at which the sensor transmits data
Correct answer: The desired target value the control system works to achieve and maintain
A setpoint is the target value (e.g., 72°F room temperature) that the controller continuously compares to the measured value to determine the corrective action needed.
Question 4: Which control strategy modulates equipment output proportionally to the difference between the measured value and the setpoint?
- On/off (two-position) control
- Proportional control (Correct answer)
- Time-of-day scheduling
- Duty cycling
Correct answer: Proportional control
Proportional control adjusts output (e.g., valve position) in direct proportion to the error signal (difference between measured value and setpoint), providing smoother control than simple on/off.
Question 5: What is 'proportional-integral-derivative' (PID) control used for in building systems?
- Scheduling equipment on/off by time of day
- Precisely controlling a variable by combining proportional, accumulated error, and rate-of-change corrections (Correct answer)
- Programming occupancy sensors to dim lights
- Sequencing multiple chillers based on load
Correct answer: Precisely controlling a variable by combining proportional, accumulated error, and rate-of-change corrections
PID control combines three correction terms to minimize steady-state error, prevent overshoot, and respond quickly to disturbances, making it ideal for temperature and pressure loops.
Question 6: In a BAS, what does the term 'trend log' refer to?
- A list of alarm events sorted by severity
- A time-stamped record of a sensor or control point value over time (Correct answer)
- A maintenance schedule for field devices
- A log of failed network communications
Correct answer: A time-stamped record of a sensor or control point value over time
A trend log records the value of a BAS point (sensor reading, output command, etc.) at regular intervals, enabling operators to analyze system behavior and diagnose issues.
BOC BOC Building Automation and Controls 1
What does BAS stand for in building operations?