Returns the properties of a .tdms file, group, or channel.
© 2017 National Instruments. All rights reserved.
Data type of the property value or values you want to return.
This input accepts the following data types:
Data Type | Default |
---|---|
Signed or unsigned integer | 0 |
Single-precision or double-precision floating-point number | 0 |
Complex single-precision or double-precision floating-point number | 0+0i |
Extended-precision floating-point number | 0 |
Alphanumeric string that does not contain null characters | Empty string |
Timestamp | 00:00:00.000 |
Boolean | False |
Variant that contains any of the data types specified above | Empty variant |
Name of the property whose values you want to get.
Refer to the Properties in a .tdms File section on the Details tab for more information about TDMS properties.
A reference to a .tdms file. Use the TDMS Open node to obtain the reference.
Channel group on which to perform the operation.
Channel on which to perform the operation.
If you wire a value to channel name, you must also wire a value to group name.
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Standard Error Behavior
Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.
Default: No error
A reference to the .tdms file.
Channel group on which you performed the operation.
If you do not specify a group name, this output returns Untitled.
Channel on which you performed the operation.
If you do not specify a channel name, this output returns Untitled.
Error information.
The node produces this output according to standard error behavior.
Standard Error Behavior
Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.
Property values of the .tdms file, group, or channel.
This output is available only if you do not wire property name.
Property value of the .tdms file, group, or channel.
This output is available only if you wire property name.
Property names of the .tdms file, group, or channel.
This output is available only if you do not wire property name.
The following table shows the inputs you must wire to search for properties at the file, group, or channel level.
Search level | Inputs to Wire | Comments |
---|---|---|
File or root level | None | Leave group name and channel name empty to search at the file or root level. |
Group level | group name | |
Channel level | group name and channel name | If channel name contains a value, group name must also contain a value. |
To get the value of a single property, wire property name and data type. If this node finds the property, found returns True and property value returns the value of the property. If this node does not find the property, found returns False and property value returns the default value of data type.
To return more than one property, leave property name and data type empty. This node returns the property names and values of the file, group, or channel you specify to search.
Every TDMS object can have an unlimited number of properties. Each TDMS property consists of a combination of a name (always a string), a data type, and a value. Typical data types for properties include numeric types such as integers or floating-point numbers, time stamps, or strings. TDMS properties do not support arrays. TDMS properties help you organize and document data and later perform searches on that data by adding meta information specific to your data set.
The following table lists all properties you might find in a .tdms file.
Property Name | Data Type | Access | Available in File Format Versions | Description |
---|---|---|---|---|
name | String | Read/write | 2.0 | Specifies the object name, such as the root name, group name, or channel name, in a .tdms file. |
NI_ArrayColumn | 32-bit signed integer | Read only | 1.0 and 2.0 | Indicates the index of a column in a 2D array. This property appears in a .tdms file only if you write a 2D array of data to the file. |
NI_ChannelLength | 64-bit unsigned integer | Read only | 1.0 and 2.0 | Represents the number of values in a channel of a .tdms file. |
NI_DataType | 16-bit unsigned integer | Read only | 1.0 and 2.0 | Represents the data type of a channel. The value is an integer that corresponds to a type code. |
NI_DigitalCompression | Boolean | Read only | 1.0 and 2.0 | Indicates whether a digital table is compressed or not. A value of 1 indicates that the digital table is compressed. If the digital table is not compressed, this property does not appear. |
NI_DigitalLine | 32-bit signed integer | Read only | 1.0 and 2.0 | Indicates the index of a row in a digital table. |
NI_DigitalNumberOfLines | 32-bit signed integer | Read only | 1.0 and 2.0 | Indicates the number of rows in a digital table. |
NI_Number_Of_Scales | 32-bit unsigned integer | Read/write | 2.0 | Specifies the number of scales to use when you read data from a .tdms file. For example, if a .tdms file has five scales and you set the value of NI_Number_Of_Scales to 4, only the first four scales are applied to the data when you read the .tdms file. |
NI_Scale[n]_config , where n represents the order of the scale and config represents the configuration of the scale. | N/A | Read/write | 2.0 | Specifies the scaling information for the data in a .tdms file. You can create more than one scale in a .tdms file. |
NI_Scaling_Status | String | Read/write | 2.0 | Specifies whether to scale data when reading the data from a .tdms file. If the value is unscaled and the .tdms file contains one or more scales, the node scales the data. If the value is scaled, the node does not scale the data. |
unit_string | String | Read/write | 1.0 and 2.0 | Specifies the unit of the channel data in a .tdms file. |
wf_increment | Double | Read/write | 1.0 and 2.0 | Represents the increment between two consecutive samples on the x-axis. |
wf_samples | 32-bit signed integer | Read/write | 1.0 and 2.0 | Represents the number of samples in the first data chunk of the waveform you write to a .tdms file. The value must be greater than zero. |
wf_start_offset | Double | Read only | 1.0 and 2.0 | Represents the first value on the x-axis used by frequency-domain data and histogram results. |
wf_start_time | Timestamp | Read only | 1.0 and 2.0 | Represents the time at which the waveform was acquired or generated. This property can be zero if the time information is relative or the waveform is not in the time domain. |
wf_time_pref | String | Read only | 1.0 and 2.0 | Indicates whether to interpret the x-axis data in absolute time or relative time. |
wf_xname | String | Read only | 1.0 and 2.0 | Indicates the name of the x-axis of the waveform. |
wf_xunit_string | String | Read only | 1.0 and 2.0 | Indicates the unit text of the x-axis. |
If the data type of a property is not valid, this node treats the property as a customized property and the property will not function as described in the table.
The following table lists all properties that do not exist in a .tdms file, but which you can use to perform certain actions.
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported
Web Server: Not supported in VIs that run in a web application