Pressure and Temperature Terminology and Definitions
Absolute Pressure: Pressure measured relative to ambient pressure.
Accuracy: The conformity of an indication to it’s true value. Accuracy is a percentage of the full scale
value.
Ambient Conditions: The surrounding environmental conditions (pressure, temperature, etc.) of the
medium surrounding the instrument.
Burst Pressure: The maximum pressure that can be applied to the bourdon tube without rupturing the
bourdon tube or causing leakage in a transmitter.
Housing/Can: The housing which covers the electronic components of a transducer/transmitter. The
majority of our products will have 316 stainless steel can/housing, however, other materials, such as
brass and carbon steel are also available.
Differential Pressure: The measured difference between two separate but related pressures.
Drift: The change in accuracy of a pressure reading over time. For example, after continued use, a
transducer/transmitter can go out of calibration. The amount of drift experienced by a
transducer/transmitter may or may not have an effect on the customer’s application.
Excitation: The external electrical voltage and/or current applied to a transducer for its proper operation.
Electrical Connection: The connection on the transducer/transmitter used to attach the wires. Our
standard connector will be the Mini DIN connector. Other connectors are available.
Gauge Pressure: Pressure measured relative to ambient atmospheric pressure.
Hysteresis: The maximum difference in output, at any measured value within the specified range,
where the value is approached first when increasing and then decreasing pressure.
Linearity: The maximum deviation of any calibration point, on a specified straight line, during any
one calibration cycle.
Life Cycle: The number of times an instrument can provide a pressure measurement within its specified
accuracy tolerance.
Proof Pressure: The maximum pressure that can be applied to the transmitter without a permanent
change in the performance of the unit.
Process Connection: The connection used to attach the transmitter to the application in the same manner
as a pressure gauge or thermometer.
Corporate Office: 121 Railside Road ● Toronto ● ON ● M3A 1B2 ● (416) 444-2345 ● Fax: (416) 444-8979
U.S.A. Office: 600 Ensminger Road ● Buffalo ● NY ● 14150 ● (716) 874-8700 ● Fax: (716) 874-8800
www.winters.com 1-800-WINTERS (946-8377)
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Pressure and Temperature Terminology and Definitions
Range and Reference Point: When a transducer and transmitter is ordered, the pressure range
required must be specified as well as the electrical signal (output). In a transmitter, where a range is
given as 0-100psi with a 4-20mA output, the pressure reading of 0psi equals 4mA and the pressure of
100 psi equals 20 mA (the maximum electrical signal).
Repeatability: The ability to reproduce output readings when the same pressure value is applied
consecutively, under the same conditions and in the same direction.
Response Time:The length of time required for the output to rise to a specified percentage of its final
value, as a result of a step change in pressure.
Thermal Error: The maximum change in output, at any pressure value within the specified range,
when the temperature is changed from room temperature to specified temperature extremes.
Thermal Sensitivity Shift: The sensitivity shift due to changes of the ambient temperature from room
temperature to the specified limits of the operating temperature range.
Thermal Zero Shift: The zero shift due to changes of the ambient temperature from room temperature
to the specified limits of the operating temperature range.
Transducer: A device that takes mechanical force (pressure) and converts it to an electrical energy. In
the case of our product offering, a transducer will be a unit with a voltage output (i.e. 1-5 Vdc,
0-5 Vdc, etc.)
Transmitter: A device that takes mechanical force (pressure) and converts it to an electrical energy. In
the case of the transmitter, the output signal will be milliamp output (4-20 mA) instead of voltage output.
Note: a transmitter may also be considered a transducer, but a transducer with strictly a voltage output should never be considered a transmitter.
Vacuum: Vacuum measured relative to ambient atmospheric pressure.
Zero/Span Adjustment: This allows the operator to adjust the unit to read a known pressure (i.e. 0 or
100 psi) so that the unit can be adjusted/calibrated in the field.
Corporate Office: 121 Railside Road ● Toronto ● ON ● M3A 1B2 ● (416) 444-2345 ● Fax: (416) 444-8979
U.S.A. Office: 600 Ensminger Road ● Buffalo ● NY ● 14150 ● (716) 874-8700 ● Fax: (716) 874-8800
www.winters.com 1-800-WINTERS (946-8377)
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