2.3.3.3.172. NXpositioner_sts

Status:

base class, extends NXobject

Description:

A generic positioner such as a motor or piezo-electric transducer.

Symbols:

No symbol table

Groups cited:

NXtransformations

Structure:

@default: (optional) NX_CHAR

Declares which child group contains a path leading ...

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.

name: (optional) NX_CHAR

symbolic or mnemonic name (one word)

description: (optional) NX_CHAR

description of positioner

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

best known value of positioner - need [n] as may be scanned

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

raw value of positioner - need [n] as may be scanned

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

targeted (commanded) value of positioner - need [n] as may be scanned

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

maximum allowable difference between target_value and value

soft_limit_min: (optional) NX_NUMBER {units=NX_ANY}

minimum allowed limit to set value

soft_limit_max: (optional) NX_NUMBER {units=NX_ANY}

maximum allowed limit to set value

velocity: (optional) NX_NUMBER {units=NX_ANY}

velocity of the positioner (distance moved per unit time)

acceleration_time: (optional) NX_NUMBER {units=NX_ANY}

time to ramp the velocity up to full speed

controller_record: (optional) NX_CHAR

Hardware device record, e.g. EPICS process variable, taco/tango …

depends_on: (optional) NX_CHAR

NeXus positions components by applying a set of translations and rotations ...

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.

z_contronller: (optional) NX_NUMBER

This controllers task is to continuously adjust the Z position of the stm tip ...

This controllers task is to continuously adjust the Z position of the stm tip in order to keep the selected control signal as close as possible to the Set Point. Different control signals lead to different contronller beahvior.

z_offset: (optional) NX_NUMBER {units=NX_LENGTH}

Offset added to the initial averaged position Zaver before starting to swepp.

tip_position_z: (optional) NX_NUMBER {units=NX_LENGTH}

Indicate the tip position Z between tip and sample. The tip position can also ...

Indicate the tip position Z between tip and sample. The tip position can also be varied when the controller is not running.

controller_name: (optional) NX_CHAR

Controller name. This name which will be displayed at places where you can sel ...

Controller name. This name which will be displayed at places where you can select a controller.

setpoint: (optional) NX_NUMBER {units=NX_CURRENT}

Set Point is the desired value of the control signal. It can be set by editing ...

Set Point is the desired value of the control signal. It can be set by editing the number or using the slider bar. Click the “Set” button above the input field to use the actual value as Set Point. The slider shows the Set Point as well as the current value.

tip_lift: (optional) NX_NUMBER {units=NX_LENGTH}

Lifts the tip by the specified amount when then controller is switched off. Th ...

Lifts the tip by the specified amount when then controller is switched off. This can be a positive or a negative number, i.e. the tip can also be moved towards the sample. Be careful with sign and value when using this feature.

switch_off_delay: (optional) NX_NUMBER {units=NX_TIME}

Use this parameter for a reproducible position when switching off the Z-contro ...

Use this parameter for a reproducible position when switching off the Z-controller. When >0 and the Z-controller is switched off, it doesn’t switch off immediately but continues to run for the specified time and averages the Z position.

z_controller_hold: (optional) NX_BOOLEAN

(In bias spectroscopy) Select whether to set the Z-Controller on hold (i.e. di ...

(In bias spectroscopy) Select whether to set the Z-Controller on hold (i.e. disabled) during the sweep. It is selected by default. When deselected, Z-offset and Z control time parameters are disabled.

final_z: (optional) NX_NUMBER {units=NX_LENGTH}

The final z-position during the bias spectroscopy scan. The availability of va ...

The final z-position during the bias spectroscopy scan. The availability of values is related to the mode of scanning.

scanfield: (optional) NX_NUMBER {units=NX_LENGTH}

Configure the scan frame like x position; y position; width; height.

pixels_line: (optional) NX_NUMBER {units=NX_COUNT}

Scan resolution by setting the Lines equal to Pixels.

lines: (optional) NX_NUMBER {units=NX_ANY}

Define the image resolution.

speed_forw: (optional) NX_NUMBER {units=NX_ANY}

Define the scan forward speed in the forward direction.

speed_backw: (optional) NX_NUMBER {units=NX_ANY}

Define the scan backward speed in the forward direction.

piezo_calibration: (optional) NX_CHAR

Piezo calibration module is used to define the X Y Z piezos calibration.

active_calib: (optional) NX_CHAR

The name of caliberation type.

calib_N: (optional) NX_NUMBER

p_gain: (optional) NX_NUMBER {units=NX_UNITLESS}

The Type switches controller parameters between :math:`P/I` (proportional gain ...

The Type switches controller parameters between \(P/I\) (proportional gain/integral gain) and \(P/T\) (proportional gain/time constant). The formula for the controller in the frequency domain is: \(G(s) = P + I/s = P(1 + 1/(Ts))\). The integral gain and time constant are related as follows: \(I = P/T\).

i_gain: (optional) NX_NUMBER {units=NX_UNITLESS}

The Type switches controller parameters between :math:`P/I` (proportional gain ...

The Type switches controller parameters between \(P/I\) (proportional gain/integral gain) and P/T (proportional gain/time constant). The formula for the controller in the frequency domain is: \(G(s) = P + I/s = P(1 + 1/(Ts))\). The integral gain and time constant are related as follows: :math:I = P/T.

time_const: (optional) NX_NUMBER {units=NX_TIME}

The Type switches controller parameters between :math:`P/I` (proportional gain ...

The Type switches controller parameters between \(P/I\) (proportional gain/integral gain) and \(P/T\) (proportional gain/time constant). The formula for the controller in the frequency domain is: \(G(s) = P + I/s = P(1 + 1/(Ts))\). The integral gain and time constant are related as follows: \(I = P/T\).

scan_contronller: (optional) NX_NUMBER

There are 2 parameters in X and Y directions. If you know them, you can enter ...

There are 2 parameters in X and Y directions. If you know them, you can enter the 2nd order piezo characteristics to compensate for it. The following equation shows the interpretation of the 2nd order correction parameter: For the X-piezo: \(Ux = 1/cx · X + cxx · X2\); with units: \([V] = [V/m] · [m] + [V/m2] · [m2]\) where cx is the calibration of the piezo X and cxx is the 2nd order correction. \((V/m^2)\)

drift: (optional) NX_NUMBER {units=NX_ANY}

There are 2 parameters in X and Y directions. Define the drift speed for all t ...

There are 2 parameters in X and Y directions. Define the drift speed for all three axes. When the compensation is on, the piezos will start to move at that speed.

drift_correction_status: (optional) NX_CHAR

Use the button to turn on/off the drift compensation.

TRANSFORMATIONS: (optional) NXtransformations

This is the group recommended for holding the chain of translation ...

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.

position: (optional) NXtransformations

To clarify the frame laboratory frame. The scanning area in x, y, and z positi ...

To clarify the frame laboratory frame. The scanning area in x, y, and z position in the frame.

Hypertext Anchors

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

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXpositioner_sts.nxdl.xml