Mantracourt Electronics Limited
SGA/A & SGA/D User Manual
20
Millivolt
One thousandth of a volt, 10
-3
volts symbol mV.
NEMA 4/ UL Type 4
A standard from the National Electrical Manufacturers Association, which
defines enclosures, intended for indoor or outdoor use primarily to
provide a degree of protection against windblown dust and rain, splashing
water, and hose-directed water.
Noise
An unwanted electrical interference on the signal wires.
Null
A condition, such as balance, which results in a minimum absolute value
of output.
Offset
Offset is otherwise identified as Zero. It relates to the proportional
output to the sensor input. Calibration of the SGA is determined by
setting the Offset (Zero) and Gain (Span).
Potentiometer
Two potentiometers (variable resistors) are used in the SGA for fine
calibration.
Pressure Transducer
The Pressure Transducer is one of a series of Strain Gauge sensors that
the SGA input is designed to accept. (Torque Sensor, Load Cell and
Temperature transducers).
Proportional Outputs
The Voltage or Current outputs are calibrated to be directly proportional
to the input from the sensor. The output is, within the sensor limits,
taken as linear and no linearity compensation is required within the SGA.
Resolution
The input corresponding to a one-unit change in the least significant digit
of the data acquisition /display equipment (Good resolution is not
necessarily equal to good accuracy.)
Sensing Element
That part of the transducer, which reacts directly in response to the
input.
Sensitivity
The minimum change in input signal to which an instrument can respond.
This is the relationship between the change in strain gauge output to the
level or magnitude of the SGA output
Signal Conditioner
A circuit module that offsets attenuates, amplifies, linearizes and/or
filters the signal for input to an A/D converter. A typical output signal
conditioning is 4 to 20 mA.
The SGA is essentially a Signal Conditioner –more specifically known as a
Strain Gauge Amplifier - in that it
conditions
(alters) the input signal from
a load cell to an electrical output
Single card assembly
The SGA has only the one Printed Circuit Board assembly on which all the
components are mounted. The assembly is then mounted inside an
environmentally rugged enclosure.
Span
Span is otherwise identified as GAIN. It relates to the proportional output
to the sensor input. Calibration of the SGA is determined by setting the
Span (Gain) and Zero (Offset).
Span Adjustment
The ability to adjust the gain of a process or strain meter so that a
specified display span in engineering units corresponds to a specified
signal span. For instance, a display span of 200°F may correspond to the
16 mA span of a 4-20 mA transmitter signal.
Stability
The quality of an instrument or sensor to maintain a consistent output
when a constant input is applied.
Strain Gauge
The strain gauge is a resistance bridge device where the bridge value
alters linearly and proportionally to the force exerted on it – be it
temperature, pressure, torque or load. The SGA is designed to convert
this change to a proportional electrical signal.
Torque Transducer
The Torque Transducer is one of a series of STRAIN GAUGE sensors that
the SGA input is designed to accept. (Torque Sensor, Load Cell and
Temperature transducers).
Zero
Zero is otherwise identified as Offset. It relates to the proportional
output to the sensor input. Calibration of the SGA is determined by
setting the Span (Gain) and Zero (Offset).
