Also referred to as a vocabulary or definition of terms, we have put together some common terms that come up in reference to our precision O2 sensors. If you run across a term you are not familiar with, contact us.
| Term | Definition |
|---|---|
| ACCURACY | The quality of closeness to a specified value under stated conditions. Usually expressed as uncertainty – the maximum deviation to be expected between a reading or output and the actual value being measured. |
| AMBIENT AIR | Often used as a term when referencing oxygen analyzer calibration. Ambient air consists of 20.9% oxygen which can be used as a known SPAN gas value. |
| AMBIENT TEMPERATURE | The minimum / maximum temperature of air surrounding the device or equipment. A critical parameter when specifying an analyzer. |
| ANALOG | A parameter which varies in a continuous, rather than incremental or discrete-step manner. |
| CALIBRATE | To determine the indication or output of a device with respect to a standard. 0 through 9, a 1/2 digit will display a 0 or 1 and overrange at 2, a 3/4 digit will display up to 3 and overrange at 4. A meter with a display span of ±3999 counts is a 33/4 digit meter. |
| EMI / RFI | Electromagnetic interference / Radio Frequency Interference. |
| EXPANDED SCALE | AAn arrangement that expands a specific portion of an overall range to occupy a larger portion of the full-scale length than it normally would. |
| EXPLOSION PROOF | An enclosure capable of withstanding an explosion of a specified gas or vapor which may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosures by sparks, flashes, heat or explosion of the gas vapor within. |
| FORM | A method for specifying relay contact configuration: Form A SPST-NO single pole, single throw, normally open Form B SPST-NC single pole, single throw, normally closed Form C SPDT single pole, double throw Change-Over CO same as SPDT |
| FULL SCALE VALUE | The arithmetic sum of the two end-scale values (may not apply to some specialized meters, such as power factor). When zero is not on the scale, the full-scale value is the higher end-scale value. Examples: Scale Full Scale Value 0-10 ppm, 0 – 100ppm, 0 – 500ppm, 0 – 1000ppm, 0 – 2500ppm, 0 – 10000ppm, 0 – 1%, 0 – 5%, 0 – 10%, 0 – 25% |
| GROUND | Reference point for an electrical system. Often used to indicate an earth connection or negative side of a DC supply. |
| LINEARITY ERROR | A measure of the departure from a straight-line response in the relationship between two quantities, where the change in one quantity is directly proportional to a change in the other quantity. Usually expressed as a maximum percent. |
| NEMA 4X / IP66 ENCLOSURE | A rating standard which defines intended use and degree of environmental protection. Typically associated with analyzers that will be installed outdoors. |
| PPM (PARTS PER MILLION) | A convenient format to express very small numbers, such as temperature coefficients. 100ppm is 0.01%. PPM is also written as “trace” as in trace oxygen. |
| PSIA (PSI Absolute) | A pressure reading using vacuum as the reference. |
| PSIG (PSI Gauge) | A pressure reading using ambient air pressure as the reference. |
| RANGE | The span of values over which a meter will function without entering overload condition, e.g. 0-100ppm |
| REPEATABILITY | The ability of an instrument to register the same reading in successive measurements of the same input. |
| RESOLUTION | The degree to which nearly equal values of a quantity can be discriminated. In digital meters, the value represented by a one-digit change in the least-significant digit. |
| SENSITIVITY | The minimum change in input to which a device can respond. |
| SHIELD | A protective conductive covering that provides a least resistance path to ground for external interference. |
| SPAN CAL ADJUSTMENT | The ability to adjust the gain of an instrument so the display value. |
| T90 RESPONSE TIME | The time required for a sensor to respond to 90% of its total change resulting from a step input. |
| TWO-WIRE TRANSMITTER | An instrument configuration in which the signal output and power input share two wires, power is transfer on one wire and returned to a PLC or DCS system via a 4 – 20mA signal on the other wire. In most cases, this signal is non-isolated. |
| ZERO CAL ADJUSTMENT | The ability to adjust an instrument so that zero output or zero display corresponds to a specific input signal, such as 0V or 4mA. |