You are here: NI Home > Support > Product Reference > Manuals > Sound and Vibration Measurement Suite 6.0 Help

Scales signal [V] from volts to the engineering units (EU) you select. You can use this polymorphic VI for single channel measurements, measurements in which the same channel information is applied to all the channels, and measurements in which each channel has its own channel information. The data types you wire to the signal [V] and channel info inputs determine the polymorphic instance to use.

Details  

Use the pull-down menu to select an instance of this VI.

Select an instance SVL Scale Voltage to EU (1 Ch)SVL Scale Voltage to EU (N Ch - 1 Info)SVL Scale Voltage to EU (N Ch - N Info)

SVL Scale Voltage to EU (1 Ch)

	signal [V] contains the signal to be scaled expressed in volts. If the signal is scaled to a different engineering unit prior to reaching the VI, the VI does not apply any scaling.
	channel info contains information about the measurement system used before the signal reaches the DAQ device. sensor sensitivity [mV/EU] specifies the sensitivity of the sensor in mV/EU. engineering units specifies the engineering units. If you are using a microphone, select Pa. If you are using an accelerometer, select g, m/s^2, or in/s^2. If the units you need are not listed, select custom and enter the unit to use in custom label. custom... V A Pa N g m/s^2 m/s m mm/s mm micron/s micron in/s^2 in/s in mil/s mil rad/s^2 rad/s rad strain dB reference [EU] is the reference value used when results are computed in decibels. dB reference [EU] is expressed in the selected engineering units. The typical decibels reference for sound pressure level is 20E–6 Pa. When engineering units is set to Pa, the dB reference [EU] is automatically set to 20E–6 Pa. custom label is the string used for units when engineering units is set to custom. If engineering units is not set to custom, this parameter is ignored. weighting filter specifies if any weighting filter has been applied to the signal. This control does not apply any weighting to the signal. weighting filter should always return linear for calibration measurements. Use weighting filter only if the acquired signal has been weighted by an external device before it is acquired by a DAQ device. If a weighting filter was applied to the signal before reaching the DAQ device, using weighting filter prevents subsequent VIs from applying any additional weighting to the weighted signal. Linear A-weighting B-weighting C-weighting ITU-R 468.4 Dolby CCITT C-message pregain [dB] is the pregain applied by an external amplifier expressed in decibels. A value of 0 dB specifies no pregain. Use pregain [dB] only if an external device amplifies the signal before a DAQ device acquires the signal. If you apply any gain with the DAQ device itself, the driver software takes this into account and you do not need to enter the information.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Refer to Controlling Error Notification to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	scaled signal [EU] returns the scaled signal expressed in the selected engineering units. scaled signal [EU] also contains channel info as an attribute of the waveform.
	unit label returns the selected engineering units.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

SVL Scale Voltage to EU (N Ch - 1 Info)

	signals [V] contains the signals to be scaled expressed in volts.
	channel info contains information about the measurement system used before the signal reaches the DAQ device. sensor sensitivity [mV/EU] specifies the sensitivity of the sensor in mV/EU. engineering units specifies the engineering units. If you are using a microphone, select Pa. If you are using an accelerometer, select g, m/s^2, or in/s^2. If the units you need are not listed, select custom and enter the unit to use in custom label. custom... V A Pa N g m/s^2 m/s m mm/s mm micron/s micron in/s^2 in/s in mil/s mil rad/s^2 rad/s rad strain dB reference [EU] is the reference value used when results are computed in decibels. dB reference [EU] is expressed in the selected engineering units. The typical decibels reference for sound pressure level is 20E–6 Pa. When engineering units is set to Pa, the dB reference [EU] is automatically set to 20E–6 Pa. custom label is the string used for units when engineering units is set to custom. If engineering units is not set to custom, this parameter is ignored. weighting filter specifies if any weighting filter has been applied to the signal. This control does not apply any weighting to the signal. weighting filter should always return linear for calibration measurements. Use weighting filter only if the acquired signal has been weighted by an external device before it is acquired by a DAQ device. If a weighting filter was applied to the signal before reaching the DAQ device, using weighting filter prevents subsequent VIs from applying any additional weighting to the weighted signal. Linear A-weighting B-weighting C-weighting ITU-R 468.4 Dolby CCITT C-message pregain [dB] is the pregain applied by an external amplifier expressed in decibels. A value of 0 dB specifies no pregain. Use pregain [dB] only if an external device amplifies the signal before a DAQ device acquires the signal. If you apply any gain with the DAQ device itself, the driver software takes this into account and you do not need to enter the information.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Refer to Controlling Error Notification to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	scaled signals returns the scaled signals expressed in the selected engineering units. To obtain a properly scaled signal, you can use the SVL Scale Voltage to EU VI or define a virtual channel in National Instruments Measurement & Automation Explorer (MAX).
	unit label returns the selected engineering units.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

SVL Scale Voltage to EU (N Ch - N Info)

	signals [V] contains the signals to be scaled expressed in volts.
	channel info contains the channel information for each channel. channel info contains information about the measurement system used before the signal reaches the DAQ device. sensor sensitivity [mV/EU] specifies the sensitivity of the sensor in mV/EU. engineering units specifies the engineering units. If you are using a microphone, select Pa. If you are using an accelerometer, select g, m/s^2, or in/s^2. If the units you need are not listed, select custom and enter the unit to use in custom label. custom... V A Pa N g m/s^2 m/s m mm/s mm micron/s micron in/s^2 in/s in mil/s mil rad/s^2 rad/s rad strain dB reference [EU] is the reference value used when results are computed in decibels. dB reference [EU] is expressed in the selected engineering units. The typical decibels reference for sound pressure level is 20E–6 Pa. When engineering units is set to Pa, the dB reference [EU] is automatically set to 20E–6 Pa. custom label is the string used for units when engineering units is set to custom. If engineering units is not set to custom, this parameter is ignored. weighting filter specifies if any weighting filter has been applied to the signal. This control does not apply any weighting to the signal. weighting filter should always return linear for calibration measurements. Use weighting filter only if the acquired signal has been weighted by an external device before it is acquired by a DAQ device. If a weighting filter was applied to the signal before reaching the DAQ device, using weighting filter prevents subsequent VIs from applying any additional weighting to the weighted signal. Linear A-weighting B-weighting C-weighting ITU-R 468.4 Dolby CCITT C-message pregain [dB] is the pregain applied by an external amplifier expressed in decibels. A value of 0 dB specifies no pregain. Use pregain [dB] only if an external device amplifies the signal before a DAQ device acquires the signal. If you apply any gain with the DAQ device itself, the driver software takes this into account and you do not need to enter the information.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Refer to Controlling Error Notification to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	scaled signals returns the scaled signals expressed in the selected engineering units. To obtain a properly scaled signal, you can use the SVL Scale Voltage to EU VI or define a virtual channel in National Instruments Measurement & Automation Explorer (MAX).
	unit labels returns the unit label for each channel.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

SVL Scale Voltage to EU Details

Use the SVL Scale Voltage to EU (1 Ch_Info N Ch) instance during the configuration phase of a measurement when all the sensors have the same sensitivity and before each channel has been independently calibrated. After the sensitivity of each channel has been determined, use the SVL Scale Voltage to EU (N Ch_Info N Ch) instance to perform the measurement.

The SVL Scale Voltage to EU VI uses a scaling factor based on the information channel info contains. You can use the SVL Calibration VIs to accurately calibrate the scaling factor. The SVL Scale Voltage to EU VI stores channel info in scaled signal [EU] as part of the attributes of the waveform for further use.

Note  If you use any method outside of the Sound and Vibration Toolkit (SVT) to apply scaling to a waveform, do not use the SVL Scale Voltage to EU VI. NI provides several tools and methods to apply scaling to a waveform. These include, but are not limited to, NI-DAQmx tasks or global channels created with Measurement & Automation Explorer (MAX), the DAQ Assistant, or the DAQmx Create Virtual Channel VI. If the input signal is scaled from volts to another engineering unit with any method outside of the SVT prior to reaching this VI, this VI does not perform any additional scaling on the signal. Any scaling information specified in channel info is ignored, and the engineering unit is read from the input signal attributes.

Note  The sensor sensitivity parameter of channel info is essential for obtaining correctly scaled measurement results when used with the SVL Scale Voltage to EU VI. Use the value from a recent calibration performed with a dedicated calibrator and the Calibration VIs for sensor sensitivity. Use the calibrated sensor sensitivity in place of the default or nominal sensor sensitivity. Alternatively, you can use the sensitivity value from the data sheet of the sensor with the SVL Scale Voltage to EU VI.