evedata.evefile.entities.metadata module

Metadata classes corresponding to the data entities.

Data without context (i.e. metadata) are mostly useless. Hence, to every class (type) of data in the evedata.evefile.entities.data module, there exists a corresponding metadata class in this module.

Overview

A first overview of the classes implemented in this module and their hierarchy is given in the UML diagram below.

Fig. 40 Class hierarchy of the evedata.evefile.entities.metadata module. Each concrete class in the evedata.evefile.entities.data module has a corresponding metadata class in this module. You may click on the image for a larger view.

A note on the AbstractDeviceMetadata interface class: The eveH5 dataset corresponding to the TimestampMetadata class is special in sense of having no PV and transport type nor an id. Several options have been considered to address this problem:

1. Moving these three attributes down the line and copying them multiple times (feels bad).

2. Leaving the attributes blank for the “special” dataset (feels bad, too).

3. Introduce another class in the hierarchy, breaking the parallel to the Data class hierarchy (potentially confusing).

4. Create a mixin class (abstract interface) with the three attributes and use multiple inheritance/implements.

As obvious from the UML diagram, the last option has been chosen. The name “DeviceMetadata” resembles the hierarchy in the scml.setup module and clearly distinguishes actual devices from datasets not containing data read from some instrument.

The following is not a strict inheritance hierarchy, but rather a grouped hierarchical list of classes for quick access to their individual API documentation:

• Metadata

  • MonitorMetadata

  • MeasureMetadata

    • DeviceMetadata

    • TimestampMetadata

    • AxisMetadata

      • NonencodedAxisMetadata

    • ChannelMetadata

      • NonnumericChannelMetadata

      • SinglePointChannelMetadata

        • SinglePointNormalizedChannelMetadata

      • AverageChannelMetadata

        • AverageNormalizedChannelMetadata

      • IntervalChannelMetadata

        • IntervalNormalizedChannelMetadata

      • ArrayChannelMetadata

        • MCAChannelMetadata

          • MCAChannelCalibration

        • ScopeChannelMetadata

      • AreaChannelMetadata

        • ScientificCameraMetadata

        • SampleCameraMetadata

      • SkipMetadata

Module documentation

class evedata.evefile.entities.metadata.Metadata

Bases: object

Metadata for the devices involved in a measurement.

This is the base class for all data(sets) and not meant to be used directly. Rather, one of the individual subclasses should actually be used.

This class complements the class evedata.evefile.entities.data.Data.

name

Name of the device.

Devices are uniquely identified by an ID that usually corresponds to the EPICS process variable (PV). However, most devices have “given” names as well that provide a more human-readable alternative.

Type:

str

options

(Scalar) options of the device.

Devices can have options. Generally, there are two types of options: those whose values are not changing within a given scan module, and those whose values can potentially change for every individual position (count). The former are stored here as key–value pairs with the key corresponding to the option name. The latter are stored in the evedata.evefile.entities.data.Data.options attribute.

Type:

dict

Examples

The Metadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.AbstractDeviceMetadata

Bases: object

Mixin class (interface) for metadata of actual physical devices.

Each physical device has a unique ID and can be accessed by an EPICS process variable (PV).

id

Unique ID of the device.

Type:

str

pv

EPICS process variable (PV) used to access the physical device.

Type:

str

access_mode

Method used to access the EPICS PV.

Type:

str

Examples

The AbstractDeviceMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

class evedata.evefile.entities.metadata.MonitorMetadata

Bases: Metadata, AbstractDeviceMetadata

Metadata for monitor data.

This class complements the class evedata.evefile.entities.data.MonitorData.

Examples

The MonitorMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.MeasureMetadata

Bases: Metadata

Metadata for data that are actually measured.

This class complements the class evedata.evefile.entities.data.MeasureData.

unit

Name of the unit corresponding to the data.

Type:

string

Examples

The MeasureMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.DeviceMetadata

Bases: MeasureMetadata, AbstractDeviceMetadata

Metadata for device data.

This class complements the class evedata.evefile.entities.data.DeviceData.

Examples

The DeviceMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.AxisMetadata

Bases: MeasureMetadata, AbstractDeviceMetadata

Metadata for axis data.

This class complements the class evedata.evefile.entities.data.AxisData.

Examples

The AxisMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.ChannelMetadata

Bases: MeasureMetadata, AbstractDeviceMetadata

Metadata for channel data.

This class complements the class evedata.evefile.entities.data.ChannelData.

Examples

The ChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.TimestampMetadata

Bases: MeasureMetadata

Metadata for the special dataset mapping timestamps to positions.

This class complements the class evedata.evefile.entities.data.TimestampData.

Examples

The TimestampMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.NonnumericChannelMetadata

Bases: ChannelMetadata

Metadata for channels with non-numeric data.

This class complements the class evedata.evefile.entities.data.NonnumericChannelData.

Examples

The NonnumericChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.SinglePointChannelMetadata

Bases: ChannelMetadata

Metadata for channels with numeric 0D data.

This class complements the class evedata.evefile.entities.data.SinglePointChannelData.

Examples

The SinglePointChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.AverageChannelMetadata

Bases: ChannelMetadata

Metadata for channels with averaged numeric 0D data.

This class complements the class evedata.evefile.entities.data.AverageChannelData.

n_averages

Number of averages

Type:

int

low_limit

Minimum value for first reading of the channel

If set, the value of the channel is read and needs to be larger than this minimum value to start the comparison phase.

Type:

float

max_attempts

Maximum number of attempts for reading the channel data.

Type:

float

max_deviation

Maximum deviation allowed between two values in the comparison phase.

If the low_limit is set, as soon as the value of the channel is larger than the low limit, the comparison phase starts. Here, two subsequent channel readouts need to be within the boundary set by max_deviation.

However, no more than max_attempts channel readouts are done.

Type:

float

Examples

The AverageChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.IntervalChannelMetadata

Bases: ChannelMetadata

Metadata for channels with numeric 0D data measured in a time interval.

This class complements the class evedata.evefile.entities.data.IntervalChannelData.

trigger_interval

The interval/rate measurements are taken in seconds

Type:

float

Examples

The IntervalChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.ArrayChannelMetadata

Bases: ChannelMetadata

Metadata for channels with numeric 1D data.

This class complements the class evedata.evefile.entities.data.ArrayChannelData.

Examples

The ArrayChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.AreaChannelMetadata

Bases: ChannelMetadata

Metadata for channels with numeric 2D data.

This class complements the class evedata.evefile.entities.data.AreaChannelData.

Examples

The AreaChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.NormalizedChannelMetadata

Bases: object

Mixin class (interface) for metadata of normalized channel data.

normalize_id

Unique ID of the channel used to normalize the data

Type:

str

Examples

The NormalizedChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

class evedata.evefile.entities.metadata.SinglePointNormalizedChannelMetadata

Bases: ChannelMetadata, NormalizedChannelMetadata

Metadata for channels with normalized numeric 0D data.

This class complements the class evedata.evefile.entities.data.SinglePointNormalizedChannelData.

Examples

The SinglePointNormalizedChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.AverageNormalizedChannelMetadata

Bases: ChannelMetadata, NormalizedChannelMetadata

Metadata for channels with normalized averaged numeric 0D data.

This class complements the class evedata.evefile.entities.data.AverageNormalizedChannelData.

Examples

The AverageNormalizedChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.IntervalNormalizedChannelMetadata

Bases: ChannelMetadata, NormalizedChannelMetadata

Metadata for channels with normalized interval-measured numeric 0D data.

This class complements the class evedata.evefile.entities.data.IntervalNormalizedChannelData.

Examples

The IntervalNormalizedChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.ScopeChannelMetadata

Bases: ArrayChannelMetadata

Metadata for oscilloscope channels.

This class complements the class evedata.evefile.entities.data.ScopeChannelData.

Examples

The ScopeChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.MCAChannelMetadata

Bases: ArrayChannelMetadata

Metadata for multichannel analyzer (MCA) channels.

This class complements the class evedata.evefile.entities.data.MCAChannelData.

calibration

Metadata for the calibration of the MCA channel.

Type:

MCAChannelCalibration

Examples

The MCAChannelMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.MCAChannelCalibration

Bases: object

Metadata for MCA channel calibration.

Many MCA channels need to be calibrated (with a second-order polynomial) to convert the channel numbers to actual energies.

From the EPICS MCA Record description: “The relationship between calibrated units (cal) and channel number (chan) is defined as cal=CALO + chan*CALS + chan^2*CALQ. The first channel in the spectrum is defined as chan=0.” Here, CALO is the offset, CALS the slope, and CALQ the quadratic term of the polynomial.

offset

Calibration offset, i.e. 0th order coefficient of the polynomial.

Type:

float

slope

Calibration slope, i.e. 1st order coefficient of the polynomial.

Type:

float

quadratic

2nd order coefficient of the polynomial.

Type:

float

Examples

To calibrate your MCA with a number of channels with the given calibration parameters (offset, slope, quadratic term), use:

calibration = MCAChannelCalibration()
# Set the calibration parameters
calibrated_values = calibration.calibrate(n_channels=4096)

The MCAChannelData object will usually perform the calibration transparently for you if necessary. Even better, this object knows how many channels the MCA has.

calibrate(n_channels=0)

Return calibrated values for given number of channels.

From the EPICS MCA Record description: “The relationship between calibrated units (cal) and channel number (chan) is defined as cal=CALO + chan*CALS + chan^2*CALQ. The first channel in the spectrum is defined as chan=0.” Here, CALO is the offset, CALS the slope, and CALQ the quadratic term of the polynomial.

Parameters:

n_channels (int) – Number of channels of the MCA

Returns:

calibrated_values – Calibrated values for the given number of channels.

Return type:

numpy.ndarray

class evedata.evefile.entities.metadata.ScientificCameraMetadata

Bases: AreaChannelMetadata

Metadata for scientific camera data.

This class complements the class evedata.evefile.entities.data.ScientificCameraData.

gain

Short description

Type:

float

reverse_x

Short description

Type:

bool

reverse_y

Short description

Type:

bool

Examples

The ScientificCameraMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.SampleCameraMetadata

Bases: AreaChannelMetadata

Metadata for consumer digital cameras used to take photos of samples.

This class complements the class evedata.evefile.entities.data.SampleCameraData.

beam_x

Position of the beam in x direction in image coordinates

Type:

int

beam_y

Position of the beam in y direction in image coordinates

Type:

int

fractional_x_position

Fractional position of the beam in x direction in image coordinates

The fractional position allows to specify the beam position independent of the image resolution.

Type:

float

fractional_y_position

Fractional position of the beam in y direction in image coordinates

The fractional position allows to specify the beam position independent of the image resolution.

Type:

float

skip_frames

Number of frames skipped

Type:

int

average_frames

Number of frames averaged

Note

May currently not be implemented in the EPICS IOC.

Type:

int

Examples

The SampleCameraMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.NonencodedAxisMetadata

Bases: AxisMetadata

Metadata for data of axes without encoders.

This class complements the class evedata.evefile.entities.data.NonencodedAxisData.

Examples

The NonencodedAxisMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.

class evedata.evefile.entities.metadata.SkipMetadata

Bases: AverageChannelMetadata

Metadata for skip detector channel.

This class complements the class evedata.evefile.entities.data.SkipData. See there for further details. Note that in this particular case, the class hierarchy of the data and metadata classes is not parallel, as this class inherits from AverageChannelMetadata. This is due to the skip detector channel being close to an average detector channel regarding its metadata, but not its actual data.

n_averages

Number of averages

Type:

int

low_limit

Minimum value for first reading of the channel

If set, the value of the channel defined in channel is read and needs to be larger than this minimum value to start the comparison phase.

Type:

float

max_attempts

Maximum number of attempts for reading the channel data.

In case of an MPSKIP EPICS channel, this value is not contained in the channel itself, but set by a counter motor axis in the same scan module. Hence, the value can only be obtained from the SCML.

Type:

float

max_deviation

Maximum deviation allowed between two values in the comparison phase.

If the low_limit is set, as soon as the value of the channel defined in channel is larger than the low limit, the comparison phase starts. Here, two subsequent channel readouts need to be within the boundary set by max_deviation.

However, no more than max_attempts channel readouts are done.

Type:

float

channel

EPICS PV of the channel whose values are read and used.

Type:

str

Examples

The SkipMetadata class is not meant to be used directly, as any entities, but rather indirectly by means of the respective facades in the boundaries technical layer of the evedata.evefile subpackage. Hence, for the time being, there are no dedicated examples how to use this class. Of course, you can instantiate an object as usual.

copy_attributes_from(source=None)

Obtain attributes from another Metadata object.

Sometimes, it is useful to obtain the (public) attributes from another Metadata object. Note that only public attributes are copied. Furthermore, a (true) copy of the attributes is obtained, hence the properties of source and target are actually different objects.

Parameters:

source (Metadata) –

Object to copy attributes from.

Should typically be of the same (super)type.

Raises:

ValueError – Raised if no source is provided to copy attributes from.