Pneumatics Final Flashcards
What is a Node?
A device that has a unique address and is attached to a network.
What type of training plan should be considered for a BAS system?
A comprehensive training plan that includes BAS training as well as HVAC system training and should be integrated with the human resources department of a facility.
What can be accomplished with an offsite portable operator terminal?
Functions include setpoint adjustments, time schedule changes, and timed overide of equipment.
What is a BAS input?
A device that senses and sends building conditions information to a controller.
What does the most common type of humidity sensor measure?
Percent relative humidity, others measure dewpoint or absolute humidity.
What is a current sensing relay?
A device which surrounds a wire and detects the resistance due to electricity passing through the wire.
What is Global Data?
Data required by all controllers in a network.
What is Closed Loop Control?
Control in which feedback occures between the controller, sensor, and controlled device.
What is an AHU Controller?
A controller that contains inputs and outputs required to operate large central-station air handling units. Control humidification, static pressure, and IAQ. Single Zone with space temp controls. Ex. Used to control VAV to maintain static pressure.
What is a Unitary Controller?
Designed for basic zone control using a standard wallmount temp sensor. Control packaged HVAC equipment such as rooftop units, heat pumps, and fan coil units. Some have supply air sensing, airflow switches, and dirty filter condition switches.
What is a Universal I/O Controller?
Designed to control most HVAC equipment. Many have same two-piece construction as ASC with fixed input-output number of inputs and outputs, 8 and 16 most common. Usu. 24 VAC power. These are field programmed, unlike ASC. On/Off output functions.
What is a Network Communication Module?
(NCM) is a controller that coordinates communication from controller to controller on a network and procides a location for operator interface. Often proprietary. Usu. 120 VAC to 24 VAC transformer.
What are Application Specific Controllers (ASC)?
Designed to control only one type of HVAC system. Preprogrammed in the factory. Cost effective. Contains EEPROM chip which allows software to be replaced.
What is a Central Supervisory Control System?
Control system in which the decision-making equipment is located in one place and the system enables/disables local (primary) controllers. Allows for Electrical demand control, duty cycling, and clock functions. 1970s. All decisions made by central location.
What is a Central Direct Digital Control System?
Control System in which all decisions are made in one location and which provides Closed Loop Control. BAS controller replaces t-stat or other controller in system. It has sensor input and sends output signal to valve, damper, etc. 1980s. Typ. Used for Supervisory Control rather than Closed Loop.
What is a Network Address?
A unique number assigned to each BAS controller on an RS-485 communications network.
What is a Dumb Terminal?
A display monitor and keyboard, with no processing capabilities. 20 to 60 lines of information only.
What is a Direct Digital Control System?
A control system in which the building automation system controller is wired directly to controlled devices and can turn them ON or OFF, or start a motion.
What is the most common controller power supply in a BAS system?
120VAC to 24VAC step-down transformer. 18 AWG stranded wire. Electrical System uses 24VAC and higher. Electronic System uses 24VAC and lower.
Describe Economizer operations?
Dry Bulb: uses OA air temp sensor and allows OA at 68 degrees and below to cool a building. Enthalpy: uses OA and RA air temp sensor and humidity sensor and selects lowest value for supply air.
