Transition Measurements

Accepts an input signal of a single waveform or an array of waveforms and measures the transition duration (rise or fall time), slew rate, preshoot, and overshoot of a selected positive or negative transition in each waveform. You can use this polymorphic VI to measure a waveform or an array of waveforms. The data type you wire to the signal in input determines the polymorphic instance to use.

Transition Measurements 1 chan

edge number specifies the transition to be measured. An edge number of n with rising polarity selected indicates that the VI will measure the nth rising transition it detects in the input waveform.
signal in is the waveform to be measured. The waveform is required to contain at least edge number transitions in the direction specified by polarity. A rising transition is the interval between adjacent rising low and high ref level crossings. A falling transition is the interval between adjacent falling high and low ref level crossings.
polarity specifies the direction of the transition to be measured as rising (default) or falling.
reference levels specifies the high and low reference levels required to determine the transition interval. mid ref level is not used in transition measurements. Reference levels provide a means to identify the position in time of the waveform feature to be measured.
high ref level specifies the high reference level of the waveform in percent (default) or absolute units. A rising high ref level crossing defines the end of a rising transition and a falling high ref level crossing defines the beginning of a falling transition.
mid ref level specifies the middle reference level in percent (default) or absolute units. mid ref level is not used in transition measurements.
low ref level specifies the low reference level of the waveform in percent (default) or absolute units. A rising low ref level crossing defines the beginning of a rising transition and a falling low ref level crossing defines the end of a falling transition.
ref units specifies whether the high, mid, and low ref level inputs are interpreted as a percentage (default) of the full range of the waveform, or as absolute levels.
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 occurs 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. 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 non-zero 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. The default is an empty string.
percent level settings specify the method used to determine the high and low state levels of a waveform. percent level settings determine the reference levels when percent ref units is selected, otherwise this input is ignored.
method specifies how the high and low state levels of the waveform are computed. Available methods are auto select (default), histogram, and peak.

auto selectdetermines if the histogram bins corresponding to the high and low state levels each have over 5% of the total hits. If so, it returns those results, otherwise, it uses the peak method. This ensures a reasonable answer for either a square wave (ignoring the overshoot and preshoot) or a triangle wave (where a histogram fails).
histogram returns the levels of the histogram bins with the maximum number of hits in the upper and lower regions of the waveform. The upper and lower regions of the waveform include the upper and lower 40%, respectively, of the waveform's peak-to-peak range.
peaksearches the entire waveform for its maximum and minimum levels.
histogram size specifies the number of bins in the histogram used to determine the high and low state levels of the waveform. histogram size is ignored if the peak method is selected.
slew rate is given by the high ref level minus the low ref level divided by the transition duration

for either rising or falling transition polarity, where high and low ref levels are in absolute units.

duration is the time span from when the waveform crosses the low ref level until it crosses the high ref level in seconds (for a rising transition polarity). The measurement starts at the left edge of the waveform and finds all low ref level crossings preceding the first high ref level crossing. The final low ref level crossing is used in the calculation. A rising polarity transition duration is known as rise time, and a falling polarity transition duration is known as fall time, as shown in the following example:

preshoot measures the height of the local minimum (maximum) preceding a rising (falling) transition as a percentage of the histogram-based amplitude of the signal. If polarity is falling,

If polarity is rising,

The state levels and amplitude are computed using the histogram method, regardless of the method specified by percent level settings.

The algorithm searches for a local minimum or maximum in a time interval immediately preceding the beginning of the transition specified by edge number and polarity. The interval starts at the middle time between the beginning of the transition specified by edge number and polarity and the end of the preceding transition. If the transition to be measured is the first in the waveform, the search interval starts at the beginning of the waveform.

overshoot measures the height of the local maximum (minimum) following a rising (falling) transition as a percentage of the histogram-based amplitude of the signal. If polarity is rising,

If polarity is falling,

The state levels and amplitude are computed using the histogram method, regardless of the method specified by percent level settings.

The algorithm searches for a local minimum or maximum in a time interval immediately following the end of the transition specified by edge number and polarity. The interval ends at the middle time between the end of the transition specified by edge number and polarity and the beginning of the following transition. If the transition to be measured is the last in the waveform, the search interval ends at the end of the waveform.

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 indicator on the front panel 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 non-zero 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.
measurement info returns the transition interval endpoints and the absolute reference levels used to define the transition.
start time specifies the time of the rising (falling) low (high) ref level crossing that defines the start of the transition to be measured.
end time specifies the time of the rising (falling) high (low) ref level crossing that defines the end of the transition to be measured.
reference levels returns the three user-defined reference levels of the waveform in absolute units. Reference levels provide a method of identifying the position in time of the waveform feature to be measured.
high ref level returns the high reference level.
mid ref level returns the middle reference level. mid ref level is not used in the transition measurements, but is provided for completeness.
low ref level returns the low reference level.
ref units is always absolute in measurement info.

Transition Measurements N chan

edge number specifies the transition to be measured. An edge number of n with rising polarity selected indicates that the VI will measure the nth rising transition it detects in the input waveform.
signal(s) in is the array of waveforms to be measured. Each waveform is required to contain at least edge number transitions in the direction specified by polarity. A rising transition is the interval between adjacent rising low and high ref level crossings. A falling transition is the interval between adjacent falling high and low ref level crossings.
polarity specifies the direction of the transition to be measured as rising (default) or falling.
reference levels specifies the high and low reference levels required to determine the transition interval. mid ref level is not used in transition measurements. Reference levels provide a means to identify the position in time of the waveform feature to be measured.
high ref level specifies the high reference level of the waveform in percent (default) or absolute units. A rising high ref level crossing defines the end of a rising transition and a falling high ref level crossing defines the beginning of a falling transition.
mid ref level specifies the middle reference level in percent (default) or absolute units. mid ref level is not used in transition measurements.
low ref level specifies the low reference level of the waveform in percent (default) or absolute units. A rising low ref level crossing defines the beginning of a rising transition and a falling low ref level crossing defines the end of a falling transition.
ref units specifies whether the high, mid, and low ref level inputs are interpreted as a percentage (default) of the full range of the waveform, or as absolute levels.
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 occurs 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. 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 non-zero 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. The default is an empty string.
percent level settings specify the method used to determine the high and low state levels of a waveform. percent level settings determine the reference levels when percent ref units is selected, otherwise this input is ignored.
method specifies how the high and low state levels of the waveform are computed. Available methods are auto select (default), histogram, and peak.

auto selectdetermines if the histogram bins corresponding to the high and low state levels each have over 5% of the total hits. If so, it returns those results, otherwise, it uses the peak method. This ensures a reasonable answer for either a square wave (ignoring the overshoot and preshoot) or a triangle wave (where a histogram fails).
histogram returns the levels of the histogram bins with the maximum number of hits in the upper and lower regions of the waveform. The upper and lower regions of the waveform include the upper and lower 40%, respectively, of the waveform's peak-to-peak range.
peaksearches the entire waveform for its maximum and minimum levels.
histogram size specifies the number of bins in the histogram used to determine the high and low state levels of the waveform. histogram size is ignored if the peak method is selected.
slew rate is given by the high ref level minus the low ref level divided by the transition duration

for either rising or falling transition polarity, where high and low ref levels are in absolute units.

duration is the time span from when the waveform crosses the low ref level until it crosses the high ref level in seconds (for a rising transition polarity). The measurement starts at the left edge of the waveform and finds all low ref level crossings preceding the first high ref level crossing. The final low ref level crossing is used in the calculation. A rising polarity transition duration is known as rise time, and a falling polarity transition duration is known as fall time, as shown in the following example:

preshoot measures the height of the local minimum (maximum) preceding a rising (falling) transition as a percentage of the histogram-based amplitude of the signal. If polarity is falling,

If polarity is rising,

The state levels and amplitude are computed using the histogram method, regardless of the method specified by percent level settings.

The algorithm searches for a local minimum or maximum in a time interval immediately preceding the beginning of the transition specified by edge number and polarity. The interval starts at the middle time between the beginning of the transition specified by edge number and polarity and the end of the preceding transition. If the transition to be measured is the first in the waveform, the search interval starts at the beginning of the waveform.

overshoot measures the height of the local maximum (minimum) following a rising (falling) transition as a percentage of the histogram-based amplitude of the signal. If polarity is rising,

If polarity is falling,

The state levels and amplitude are computed using the histogram method, regardless of the method specified by percent level settings.

The algorithm searches for a local minimum or maximum in a time interval immediately following the end of the transition specified by edge number and polarity. The interval ends at the middle time between the end of the transition specified by edge number and polarity and the beginning of the following transition. If the transition to be measured is the last in the waveform, the search interval ends at the end of the waveform.

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 indicator on the front panel 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 non-zero 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.
measurement info returns the transition interval endpoints and the absolute reference levels used to define the transition for each waveform.
start time specifies the time of the rising (falling) low (high) ref level crossing that defines the start of the transition to be measured.
end time specifies the time of the rising (falling) high (low) ref level crossing that defines the end of the transition to be measured.
reference levels returns the three user-defined reference levels of the waveform in absolute units. Reference levels provide a method of identifying the position in time of the waveform feature to be measured.
high ref level returns the high reference level.
mid ref level returns the middle reference level. mid ref level is not used in the transition measurements, but is provided for completeness.
low ref level returns the low reference level.
ref units is always absolute in measurement info.