Junction: A thermocouple junction is the point at which
two alloys are joined. A typical thermocouple circuit
would have a measuring and a reference junction.
Junction: A thermocouple junction is the point at which
two alloys are joined. A typical thermocouple circuit
would have a measuring and a reference junction.
Kelvin: The unit of absolute or thermodynamic temperature
scale. Zero Kelvin is absolute zero, where all molecular
activity stops. No " " symbol is used. 0 °C= 273.15K;
100 °C =373.15K.
Kelvin: The unit of absolute or thermodynamic temperature
scale. Zero Kelvin is absolute zero, where all molecular
activity stops. No " " symbol is used. 0 °C= 273.15K;
100 °C =373.15K.
Kilo: The prefix for one thousand (K).
Kilo: The prefix for one thousand (K).
Kilowatt (kw): 1000 watts or 3412Btu per hour.
Kilowatt (kw): 1000 watts or 3412Btu per hour.
Lag: 1. A time delay between the output of a signal and
the response of the instrument to which the signal is
sent. 2. A time relationship between two waveforms
where a fixed reference point on one wave occurs
after the same point of the reference wave.
Lag: 1. A time delay between the output of a signal and
the response of the instrument to which the signal is
sent. 2. A time relationship between two waveforms
where a fixed reference point on one wave occurs
after the same point of the reference wave.
Load: The electrical demand of a process expressed as
power (watts), current (amps) or resistance (ohms).
Load: The electrical demand of a process expressed as
power (watts), current (amps) or resistance (ohms).
Least Significant Digit (LSD): The digit farthest to the right
in a display.
Least Significant Digit (LSD): The digit farthest to the right
in a display.
Linearity: The deviation of an instrument's response from
a straight line.
Linearity: The deviation of an instrument's response from
a straight line.
Manual reset: The adjustment on a proportional control
which shifts the proportional band in relation to the set
point to eliminate droop of offset errors.
Manual reset: The adjustment on a proportional control
which shifts the proportional band in relation to the set
point to eliminate droop of offset errors.
Mega: The prefix for one million (M) (10 ).
Mega: The prefix for one million (M) (10 ).
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Mechanical relay: An electromechanical device that
completes or breaks a circuit by opening or closing
electrical contacts.
Mechanical relay: An electromechanical device that
completes or breaks a circuit by opening or closing
electrical contacts.
Mico: The prefix for one millionth (10 ).
Mico: The prefix for one millionth (10 ).
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Microamp: 10 amps (one millionth of an amp).
Microamp: 10 amps (one millionth of an amp).
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Micron: 10 meters (one millionth of a meter).
Micron: 10 meters (one millionth of a meter).
Maximum operating temperature: The maximum
temperature at which an instrument or sensor can be
safely operated.
Maximum operating temperature: The maximum
temperature at which an instrument or sensor can be
safely operated.
Maximum power rating: The maximum power in watts
that a device can safely handle.
Maximum power rating: The maximum power in watts
that a device can safely handle.
Measuring junction: The thermocouple junction referred
to as the hot junction that is used to measure an
unknown temperature.
Measuring junction: The thermocouple junction referred
to as the hot junction that is used to measure an
unknown temperature.
Joule : The basic unit of thermal energy. 1 Joule equals 1
ampere passed through a resistance of 1 ohm for 1
second.
Joule : The basic unit of thermal energy. 1 Joule equals 1
ampere passed through a resistance of 1 ohm for 1
second.
ITS-90: International Temperature Scale of 1990
ITS-90: International Temperature Scale of 1990
Isolation: Electrical Separation
Isolation: Electrical Separation
Isothermal: A process or area that maintains a constant
temperature.
Isothermal: A process or area that maintains a constant
temperature.
Hi-Pot test : To apply a high voltage to an electrical
conductor to test the surrounding insulation.
Hi-Pot test : To apply a high voltage to an electrical
conductor to test the surrounding insulation.
Hysteresis: In ON/OFF control, the temperature change
necessary to change the output from full ON to full OFF.
Hysteresis: In ON/OFF control, the temperature change
necessary to change the output from full ON to full OFF.
Hunting: Oscillation or fluctuation of process temperature
between set point and process variable.
Hunting: Oscillation or fluctuation of process temperature
between set point and process variable.
IE: Integrated error
IE: Integrated error
IAE: Integrated absolute error
IAE: Integrated absolute error
ISE: Integrated squared error
ISE: Integrated squared error
Impedance: The total opposition in a circuit to the flow of
electrical current. Measured in ohms and represented
by "Z".
Impedance: The total opposition in a circuit to the flow of
electrical current. Measured in ohms and represented
by "Z".
ISA: Instrument Society of America.
ISA: Instrument Society of America.
Ice point: The temperature at which pure water freezes.
0 °C, 32 °F, 273.16K.
Ice point: The temperature at which pure water freezes.
0 °C, 32 °F, 273.16K.
Infrared: Or radiation is the exchange of energy by
electromagnetic waves. The infrared spectrum extends
from the deep red end of the visible spectrum to the
microwave region of the radio spectrum, the portion
adjacent to the visible spectrum is of importance to
heating. Radiant heat transfer can be very efficient in
directing energy from the heat source to an object.
Infrared: Or radiation is the exchange of energy by
electromagnetic waves. The infrared spectrum extends
from the deep red end of the visible spectrum to the
microwave region of the radio spectrum, the portion
adjacent to the visible spectrum is of importance to
heating. Radiant heat transfer can be very efficient in
directing energy from the heat source to an object.
Interchangeability error: A measurement error that can
occur if two or more probes are used to make the
same measurement. It is caused by a slight variation
in characteristics of different probes.
Interchangeability error: A measurement error that can
occur if two or more probes are used to make the
same measurement. It is caused by a slight variation
in characteristics of different probes.
Intrinsically safe: An instrument which will not produce
any spark or thermal effects under normal or abnormal
conditions that will ignite a specified gas mixture.
Intrinsically safe: An instrument which will not produce
any spark or thermal effects under normal or abnormal
conditions that will ignite a specified gas mixture.
IPTS-68: International Practical Temperature Scale of
1968. Fixed points in thermometry set by the 1968
General Conference of Weights and Measures.
IPTS-68: International Practical Temperature Scale of
1968. Fixed points in thermometry set by the 1968
General Conference of Weights and Measures.
Integral: (See Automatic Reset).
Integral: (See Automatic Reset).
Microprocessor: The central processing unit (CPU) that
performs the logic operations in a micro-computer
system. The microprocessor in a process or instrument
control decodes instructions from the stored program,
performs algorithmic and logic functions, and produces
signals and commands.
Microprocessor: The central processing unit (CPU) that
performs the logic operations in a micro-computer
system. The microprocessor in a process or instrument
control decodes instructions from the stored program,
performs algorithmic and logic functions, and produces
signals and commands.
Milliamp: 10 amps (one thousandth of an amp).
Milliamp: 10 amps (one thousandth of an amp).
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Millivolt: 10 volts (one thousandth of a volt).
Millivolt: 10 volts (one thousandth of a volt).
NEC: National Electrical Code
NEC: National Electrical Code
NEMA: National Electrical Manufacturer's Association
NEMA: National Electrical Manufacturer's Association
Milli: The prefix for one thousandth (10 )
Milli: The prefix for one thousandth (10 )
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Melting point: The temperature at which a substance
transforms from a solid phase to a liquid phase.
Melting point: The temperature at which a substance
transforms from a solid phase to a liquid phase.
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