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Glossary
120
Building Technologies 125-202
06/06/2017
Glossary
Word Description
Amp Multiplier A multiplier that changes amperage so that a meter can read higher measurements.
Analog Value A type of BACnet object that is a floating point number. On the MD-BMS and MD-BMED Model Power Meters, Analog
Value objects are used to represent the electrical measurements.
BACnet Building Automation Control networks. A communications protocol that allows building automation and control devices
and their association properties (objects) to be automatically discovered.
CAM Clear All Measurements
Data Scalar A scalar is used to multiply the raw data value to convert information read from the registers
Demand Window The Demand Window is how long the meter calculates your demand for recording a value. For example if your Demand
Window is set to 15 minutes, the meter will calculate your total demand every minute for 15 minutes. At the end of the 15
minutes it will sum all 15 values, and then record that value as the demand.
Digital Output The MD-BMS and MD-BMED Power Meters have an output port. The port can be used to output kWh, kVARh, or kVAh
pulses to external devices, or to toggle on and off to control a remote device or relay.
Discovery In BACnet, devices and the objects they expose can be found through a discovery process. This means that devices and
objects do not need to be manually added if a BACnet client supports discovery.
Falling edge Transition of the input signal from high to low.
Hexadecimal In mathematics and computer science, hexadecimal (or hex) is a numeral system with a radix, or base, of 16. It uses
sixteen distinct symbols, most often the symbols 0 to 9 to represent values zero to nine, and A, B, C, D, E, F (or a
through f) to represent values ten to fifteen.
kVAh Kilovolt-Ampere Hour
kVARh Kilovolt Ampere Reactive Hours
kWh Kilowatt Hour
LSB Least significant bit
LSW (Modbus mode only) Least Significant Word. Unit of data with the low-order bytes at the right.
MS/TP Master-Slave/Token Passing is a model of communication used by BACnet where one device (the master node) has
unidirectional control of the RS-485 serial bus. The token is passed from master node to master node to allow a master
node to send frames over the bus.
MSB Most significant bit
MSW (Modbus mode only) Most Significant Word. Unit of data with the high-order bytes at the left.
Net When a register/object has the word “net” in its description, the net equals the sum of all individual signed
measurements.
Object A BACnet object is a standard data structure that on the MD Model Power Meter represents electrical measurements.
Power Factor The power factor of the AC electric power system is defined as the ratio of the real power flowing to the load to the
apparent power, and is a number between 0 and 1 (frequently expressed as a percentage, for example, 0.5 pf = 50% pf).
Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the root
mean squared current and root mean squared voltage of the circuit. Due to energy stored in the load and returned to the
source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power
can be greater than the real power.
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