base class, extends NXobject


A sensor used to monitor an external condition

The condition itself is described in NXenvironment.


No symbol table

Groups cited:

NXgeometry, NXlog, NXoff_geometry, NXorientation, NXtransformations


@default: (optional) NX_CHAR

Declares which child group contains a path leading to a NXdata group.

It is recommended (as of NIAC2014) to use this attribute to help define the path to the default dataset to be plotted. See https://www.nexusformat.org/2014_How_to_find_default_data.html for a summary of the discussion.

model: (optional) NX_CHAR

Sensor identification code/model number

name: (optional) NX_CHAR

Name for the sensor

short_name: (optional) NX_CHAR

Short name of sensor used e.g. on monitor display program

attached_to: (optional) NX_CHAR

where sensor is attached to (“sample” | “can”)

measurement: (optional) NX_CHAR

name for measured signal

Any of these values:

  • temperature

  • pH

  • magnetic_field

  • electric_field

  • conductivity

  • resistance

  • voltage

  • pressure

  • flow

  • stress

  • strain

  • shear

  • surface_pressure

type: (optional) NX_CHAR

The type of hardware used for the measurement. Examples (suggestions but not restrictions):


J | K | T | E | R | S | Pt100 | Rh/Fe


Hg/Hg2Cl2 | Ag/AgCl | ISFET

Ion selective electrode:

specify species; e.g. Ca2+

Magnetic field:


Surface pressure:

wilhelmy plate

run_control: (optional) NX_BOOLEAN

Is data collection controlled or synchronised to this quantity: 1=no, 0=to “value”, 1=to “value_deriv1”, etc.

high_trip_value: (optional) NX_FLOAT {units=NX_ANY}

Upper control bound of sensor reading if using run_control

low_trip_value: (optional) NX_FLOAT {units=NX_ANY}

Lower control bound of sensor reading if using run_control

value: (optional) NX_FLOAT (Rank: 1, Dimensions: [n]) {units=NX_ANY}

nominal setpoint or average value - need [n] as may be a vector

value_deriv1: (optional) NX_FLOAT (Rank: same as field value, Dimensions: same as field value) {units=NX_ANY}

Nominal/average first derivative of value e.g. strain rate - same dimensions as “value” (may be a vector)

value_deriv2: (optional) NX_FLOAT (Rank: same as field value, Dimensions: same as field value) {units=NX_ANY}

Nominal/average second derivative of value - same dimensions as “value” (may be a vector)

external_field_brief: (optional) NX_CHAR

Any of these values:

  • along beam

  • across beam

  • transverse

  • solenoidal

  • flow shear gradient

  • flow vorticity

depends_on: (optional) NX_CHAR

NeXus positions components by applying a set of translations and rotations to apply to the component starting from 0, 0, 0. The order of these operations is critical and forms what NeXus calls a dependency chain. The depends_on field defines the path to the top most operation of the dependency chain or the string “.” if located in the origin. Usually these operations are stored in a NXtransformations group. But NeXus allows them to be stored anywhere.

geometry: (optional) NXgeometry

DEPRECATED: Use the field depends_on and NXtransformations to position the beamstop and NXoff_geometry to describe its shape instead

Defines the axes for logged vector quantities if they are not the global instrument axes.

value_log: (optional) NXlog

Time history of sensor readings

value_deriv1_log: (optional) NXlog

Time history of first derivative of sensor readings

value_deriv2_log: (optional) NXlog

Time history of second derivative of sensor readings

external_field_full: (optional) NXorientation

For complex external fields not satisfied by External_field_brief

OFF_GEOMETRY: (optional) NXoff_geometry

This group describes the shape of the sensor when necessary.

TRANSFORMATIONS: (optional) NXtransformations

This is the group recommended for holding the chain of translation and rotation operations necessary to position the component within the instrument. The dependency chain may however traverse similar groups in other component groups.

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source: