Direct Digital Controls and Lab Practice Test

These questions are part of the practice quiz. Start practicing

• What is the purpose of a trend log in a DDC system?
• In an NTC sensor, what happens to resistance as temperature rises?
• A parallel device is defined as which of the following?
• Which technique is specifically used to limit the speed of actuator output changes to prevent instability during saturation?
• What is 'sequencing' in DDC and provide an example.
• Which statement best describes Modbus RTU usage in field devices?
• Data logging is the recording of information such as temperature and equipment On/OFF status at regular intervals. Which option best describes this concept?
• Controller analog output terminals are commonly labeled what, including their common return?
• One of the primary reasons for poor customer satisfaction with a building automation system is which of the following?
• Which instrument is commonly used to check electrical current in DDC wiring?
• Global data includes data such as outside air temperature and electrical demand. Which statement best describes this data?
• What is the role of an HMI in a DDC system?
• What is the purpose of a fail-safe in fault detection and diagnostics (FDD) for DDC?
• What best describes a distributed direct digital control system?
• Which of the following is NOT a typical humidity measurement?
• In commissioning a new DDC controller, what is the purpose of loading a baseline program and validating with the real process?
• Central direct digital control systems are typically used for supervisory control instead of closed loop control. Which option expresses this?
• In modern DDC programming, what is a function block and give an example?
• What is a building automation system?
• What is a common nominal thermistor value and its temperature?
• Which device contains a paddle that moves when contacted by air or water flow?
• Which protocol runs over Ethernet and is commonly used for device interconnection within a building automation system?
• When loaded with the appropriate software, a notebook PC can function as a portable service/maintenance tool that can be used to
• A daisy chain network configuration is a topology in which multiple controllers are connected in which arrangement?
• Which statement best describes a direct digital control system?
• Alarm is a notification of improper temperature or other condition existing in a building. Which option best defines an alarm?
• What is the function of a dampers actuator in an HVAC system controlled by DDC?
• A DIN rail is defined as?
• Why are commissioning tests critical after installation?
• Which guidance should be followed for wiring building automation controllers?
• RS-485 is best described as a multipoint communication standard that incorporates which features?
• In BAS terminology, which term is used to describe the device usually associated with the desktop workstation that communicates with the system?
• A node is a device, such as a computer or printer, that has a unique address and is attached to a network.
• Which statement best describes the purpose of optoisolation?
• Which input method is used by a voice phone interface in BAS?
• A thermostat is what?
• Global data is data needed by all HVAC controllers in a network, including outside air temperature and electrical demand.
• Which statement best describes central supervisory control system?
• Which term best describes the device that allows an individual to access and respond to building automation system information?
• In a building automation network, a multipoint communication in RS-485 refers to which scenario?
• What term describes a small, lightweight, hand-held device that provides access to basic BAS functions from various controllers throughout a building?
• Define a sensor's span and its importance in DDC calibration.
• In BAS, who is typically authorized to assign access levels and codes to other individuals?
• How would you detect a stuck actuator in a DDC loop?
• Software is ...
• Central direct digital control systems are typically used for which type of control?
• A pseudopoint is a point that exists only in software and is not a hard-wired point.
• What is a ladder diagram and in what context might a DDC use it?
• A variable air volume (VAV) box controller is ...
• What is scaling in relation to sensor signals?
• An air handling unit (AHU) controller is ...
• Which of the following describes sensor span?
• Which term refers to a controller-mounted device with a small number of keys and a display?
• A universal input-output controller is ...
• When controllers are located close together, what is recommended regarding transformers?
• What is the role of alarms and fault diagnostics in DDC systems?
• What is 'schedule-based control' in DDC?
• How would you test a 4-20 mA loop in a DDC lab?
• Digital inputs are commonly configured as what?
• What is a building automation system input?
• Field interface device is an electronic device that follows commands sent to the device from the CPU of a central-direct digital control system. Which option correctly defines this device?
• Why do manufacturers provide sunshields for outside air temperature sensors?
• Gateway interface modules provide a connection between central supervisory control systems and modern building automation networks. Which option correctly describes their role?
• An EEPROM memory chip is ...
• Which component is most directly responsible for defining the measurement range and linearity of the sensed variable in a DDC system?
• In the Ziegler-Nichols tuning method, what is the starting point to determine PID parameters?
• An application-specific controller is ...
• Define a fan coil unit (FCU) and how DDC controls it.
• Which device is a digital output used to position a motor?
• What effect does actuator saturation have on a controller, and how can it be mitigated?
• What is a primary reason to implement redundancy in DDC systems?
• Name two common sensor errors and how to diagnose them in a lab.
• When testing RS-485 wiring, the voltage should be between which values?
• What is the significance of 'version control' for DDC program files?
• A ground loop is best described as which of the following?
• What is a jumper?
• At what rate do humidity sensors commonly drift?
• What type of signal does an analog input provide to the controller?
• Which capability distinguishes EEPROM memory from other memory types?
• Which statement best describes setpoint scheduling in a direct digital control system?
• In humidity sensing, besides relative humidity, what other measurements may be provided?
• A local area network is a communication network that spans a relatively small area.
• Which term describes a point existing only in software and not in hard-wired hardware?
• In BAS security, what is an access level?
• What happens if time constants are too short in a DDC loop?
• What is the primary purpose of a direct digital controller in building automation?
• For a negative temperature coefficient (NTC) sensor, how does resistance change with temperature?
• In lab practice, why is it important to establish a safe operating envelope before testing a control loop?
• Which device surrounds a wire and detects the electromagnetic field due to electricity passing through the wire?
• Which device accepts an on or off signal?
• Which devices can a building automation system send alarms and logs to besides off-site PCs?
• Which term describes the printer used with a BAS to produce hard copies of alarms, preventive maintenance messages, and data trends?
• Optoisolation is a communication method in which controllers use photonic components to achieve what benefit?
• What step is essential when performing a loop check to confirm actuator movement?
• What is the relationship between the process variable and the setpoint in a control loop?
• Which of the following describes Ethernet in a BAS context?
• Which statement best describes a peripheral device in automation systems?
• Which term describes a device that has a unique address attached to a network?
• What does an analog input do in a building automation system?
• Which device is used to produce hard copies of alarms and data trends in a building automation system?
• When testing RS-485 wiring, the voltage between RS-485+ and RS-485- should be between which range?
• A central supervisory control system is characterized by which description?
• Explain BACnet and its role in DDC integration.
• Central direct digital control systems are typically used for:
• Which sequence best describes typical steps to commission a new DDC controller in a lab?
• In a PID control system, what does the acronym PID stand for?
• A notebook docking station is best described as which of the following?
• A thermistor is typically made from which material?
• What are the typical output types from a DDC to control HVAC devices?
• How do time constants influence the response of a DDC-controlled system?
• What is a control loop's deadband and why is it important in DDC?
• In automation systems, which statement best describes a peripheral device?
• Which type of controller is designed for basic zone control using a standard wall-mounted temperature sensor?
• What is the difference between analog input and digital input on a DDC?
• What do most humidity sensors measure?
• What is a 'hard alarm' vs 'soft alarm' in a DDC system?
• Which three main components make up a DDC loop in a typical HVAC application?
• Describe Ziegler-Nichols method for PID tuning in a practical lab context.
• Compare direct digital control versus limit switching with a thermostat in simple terms.
• What is LonWorks and how does it relate to DDC?
• Which term corresponds to the integral action in a PID controller?
• What best describes a voice phone interface in a building automation context?
• How is the operator interface for a building automation system selected?
• Which device changes the state of a controlled device in response to a command from a building automation system controller?
• What is the primary purpose of fault diagnostics in DDC systems?
• Which description best defines a thermistor?
• A latching relay is a relay that requires a short pulse to energize the relay.
• Central direct digital control system is a control system in which all decisions are made in one location and that provides closed loop control. Which option correctly describes this type of system?
• LonWorks relates to DDC by enabling distributed control across devices. To emphasize this, which option correctly completes the statement with the most precise phrasing?
• An incremental output is a digital output device used to position a bi-directional electric motor.
• Which of the following is NOT listed as a recipient of BAS alarms besides off-site PCs?
• The most common power supply converts 120 VAC to what secondary voltage for controllers?
• Which device enables an off-site desktop PC to access a building automation system, or allows the building automation system to dial in to the off-site PC?
• The primary desktop PC used to communicate with a building automation system is commonly referred to as the front end.
• Name two common sensor types used for temperature measurement in DDC and one key characteristic.
• Serial information is information that is transmitted sequentially one bit at a time. Which option correctly defines serial information?
• Operator interfaces commonly require installation at what height above finished floor for viewing by maintenance personnel?
• What is the primary function of software in a controller?
• A comprehensive training plan for building automation should include BAS training as well as which other component(s) and should be integrated with which department?
• What is the purpose of a bias in sensor readings and how is it corrected?
• A network communication module is ...
• Which technology is a building automation control networking platform designed for distributed control across devices?
• Which statement best describes a recommended safe wiring practice for DDC devices in a laboratory setting?
• Which of the following describes offset as a sensor error?
• Which description matches a dumb terminal?
• A unitary controller is ...
• How would you perform a calibration of a pressure sensor in a lab?
• Which device surrounds a wire to detect the electromagnetic field due to current?
• In a typical DDC lab setting, what is a common outcome after applying Ziegler-Nichols tuning before further refinement?
• A dumb terminal can display how many lines of information?
• A differential pressure switch responds to what?
• What is the purpose of anti-windup in control systems?
• Which device, when closed, sends a signal to a controller indicating that a timed override period is to begin?
• What is the purpose of a setpoint in a control loop?
• The coefficient of a thermistor sensor is defined as what?
• Why is calibration of sensors important in a DDC lab practice test?
• During a loop check for a temperature control loop, which action helps verify correct sensor reading?
• What is hysteresis in valve control, and how can it influence performance?
• What is the purpose of a signal conditioner in a DDC system?
• What is a network address?
• Which term best describes a terminal that can display 20 to 60 lines of information?
• In PID terms, what is the relationship between proportional band and gain?
• What is integral windup, and how is it avoided in DDCs?
• What is the meaning of 'redundancy' in DDC systems and why is it used?
• The most common controller power supply is which of the following?
• What is loop isolation and why is it important in lab testing?
• Central direct digital control systems are typically used for:
• Which statement best describes a dumb terminal?
• Which term describes a controller-mounted device that consists of a small number of keys and a small display?
• Which of the following represents a valid approach to preventing integral windup?
• Operators and technicians are issued what type of codes to activate their access level?
• What is a foot candle?
• What safety considerations should you take when wiring DDC devices in a lab?
• A notebook docking station typically includes which combination of features?
• Which statement best describes the benefit of version control for DDC program files?
• Which statement defines an incremental output?
• Which guideline applies to wiring all building automation controllers?
• What is the role of a fail-safe in DDC Fault Detection and Diagnostics?
• Pulse width modulation is a control technique in which a sequence of short pulses is used to position an actuator.
• Which unit is used to express illuminance in the context of lighting measurements?
• What safety procedure should be followed before performing electrical lab tasks on DDC equipment?
• Explain the difference between a Proportional (P) control and a Proportional-Integral (PI) control in DDC.
• Some manufacturers provide gateway interface modules that enable communication with modern building automation system networks. Which statement best describes their function?
• What is Modbus RTU and when would you use Modbus TCP in a DDC system?
• How does a positive temperature-coefficient device change its output resistance with temperature?
• Why is RS-485 favored in noisy environments?
• Data logging is the recording of information such as temperature and equipment On/OFF status at regular intervals. Which option expresses this definition?
• Which device records the number of occurrences of a signal?
• What is the primary purpose of a trend log in a DDC system?
• What does the supervisor level allow in BAS access control?
• A common nominal value of 1000Ω for a thermistor is specified at which temperature?
• Which term describes data needed by all HVAC controllers in a network, including outside air temperature and electrical demand?
• What is a deadband vs a hysteresis in control systems?
• The operator interface is selected based on which factor?
• Which device requires a short pulse to energize a relay?