Level Plus
®
LevelLimit
®
Operation Manual
I
4
I
2. Terms and definitions
6A Heavy Oils
‘Generalized Crude Oils’, Correction of Volume to 60 °F against API
Gravity.
6B Light Oils
‘Generalized Products’, Correction of Volume to 60 °F against API
Gravity.
6C Chemical
‘Volume Correction Factors (VCF)’ for individual and special
applications, volume correction to 60 °F against thermal expansion
coefficients.
6C Mod
An adjustable temperature reference for defining VCF.
A
API gravity
The measure of how heavy or light a petroleum liquid is compared to
water. Allowable values are 0 to 100 degrees
API
for
(6A)
and 0 to 85
degrees
API
for
(6B)
.
D
DDA (Direct Digital Access)
The proprietary digital protocol developed by MTS for use in
intrinsically safe areas.
Density
Mass divided by the volume of an object at a specific temperature. The
density value should be entered as lb / cu. ft..
Digital I/O
Represents a binary input and output signal that is either in a high or
low state. The LevelLimit generates an output signal that is HI when
the switch float is sitting at rest on the stop collar and LO when switch
float is no longer at rest.
E
Explosion proof
Type of protection based on enclosure in which the parts which can
ignite an explosive gas atmosphere are placed within, and which
can withstand the pressure developed during an internal explosion
of an explosive mixture, and which prevents the transmission of the
explosion to the explosive gas atmosphere surrounding the enclosure.
F
Flameproof
Type of protection based on enclosure in which the parts which can
ignite an explosive gas atmosphere are placed within and which can
withstand the pressure developed during an internal explosion of
an explosive mixture, and which prevents the transmission of the
explosion to the explosive gas atmosphere surrounding the enclosure.
G
GOVI (Gross Observed Volume of the Interface)
The total volume of the tank occupied by the interface liquid. The
GOVI
is only given when measuring two liquids and is calculated by
subtracting the volume of the product from the total volume of liquid
in the tank (
GOVT – GOVP
).
GOVP (Gross Observed Volume of the Product)
The total volume of the tank occupied by the product liquid. When
measuring only one liquid, it is also the total volume of liquid
in the tank (
GOVT
). When measuring two liquids it is the total
volume of liquid in the tank minus the volume of the interface liquid
(
GOVT – GOVI
).
GOVT (Total Gross Observed Volume)
The total volume of liquid in the tank. When measuring only one liquid
it is equal to the volume of the product (
GOVP
). When measuring two
liquids it is equal to the volume of the product and interface liquids
(
GOVP + GOVI
).
GOVU (Gross Observed Volume Ullage)
The difference in volume between the working capacity of a tank and
the total volume in the tank (Working Capacity –
GOVT
).
H
HART
®
A
Bidirectional communication protocol
that provides data access
between intelligent field instruments and host systems.
I
Interface
Noun
; The measurement of the level of one liquid when that liquid is
below another liquid.
Interface
Adj
.; The Software
Graphical User Interface
(GUI) that allows the user
to access software protocols (
HART
®
, DDA, MODBUS
).
Intrinsic safety
‘Intrinsically safe’ - Type of protection based on the restriction of
electrical energy within apparatus of interconnecting wiring exposed to
potentially explosive atmosphere to a level below that which can cause
ignition by either sparking or heating effects.
