GL.7
Date Code 20090730 Instruction Manual SEL-734 Meter
Glossary
Maximum Dropout Time—NOT Operator
Maximum Dropout Time
The maximum time interval following a change of input conditions between
the deassertion of the input and the deassertion of the output.
Maximum/Minimum
Meter
Type of meter data presented by the SEL-734 that includes a record of the
maximum and minimum of each value, along with the date and time that each
maximum and minimum occurred.
Meter Form
The design of the measuring portion of the electric meter so that the meter can
correctly measure the electric service supplied by the utility. There are many
different forms because of the different types of electric service and the size of
the service. Meter forms are defined in ANSI C12.10. Socket-based meters
use an “S” suffix in the form number, e.g., “2S.” Bottom-connected meters,
also known as “A-base” meters, use an “A” suffix, e.g., “9A.” The commonly
used residential meter is the Form 2S, three-wire, self-contained. It is used on
a 120/240 V service. The Form 9 meter is commonly used in substation
metering. A Form 9 meter is a three-stator, transformer-rated, three-phase,
four-wire wye.
Meter Word Bit
A single meter element or logic result. A Meter Word bit can equal either
logical 1 or logical 0. Logical 1 represents a true logic condition, picked up
element, or asserted control input or control output. Logical 0 represents a
false logic condition, dropped out element, or deasserted control input or
control output. Use Meter Word bits in SEL
OGIC control equations.
MID
Meter firmware identification string. Lists the meter model, firmware version
and date code, and other information that uniquely identifies the firmware
installed in a particular meter.
MIRRORED BITS
®
Communications
Patented meter-to-meter communications technique that sends internal logic
status, encoded in a digital message, from one meter to the other. Eliminates
the need for some communications hardware.
MMS
Manufacturing Messaging Specification, a data exchange protocol used by
UCA.
Model
Model of device (or component of a device) including the data, control access,
and other features in UCA protocol.
Negation Operator
A SELOGIC control equation math operator that changes the sign of the
argument. The argument of the negation operation is multiplied by –1.
Negative-Sequence
A configuration of three-phase currents and voltages. The currents and
voltages have equal magnitude and a phase displacement of 120°, and have
clockwise phase rotation with current and voltage maxima that occur
differently from that for positive-sequence configuration. If positive-sequence
maxima occur as ABC, negative-sequence maxima occur as ACB.
NEMA
National Electrical Manufacturers’ Association.
NONVOL
Nonvolatile memory where meter settings, event reports, SER records, and
other nonvolatile data are stored.
Nonvolatile Memory
Meter memory that persists over time to maintain the contained data even
when the meter is de-energized.
NOT Operator
A logical operator that produces the inverse value.
Courtesy of NationalSwitchgear.com
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