Vernier LoggerPro Function Reference

LoggerPro functions for use in Calculated Columns.  I always Google for this information and can never find it online.  It is hidden in the “Help” for LoggerPro (who would think to look there!?).

Functions

– Trigonometric functions will use degrees or radians as set in the Settings for (file name) in the File menu.

– For more information about Savitsky-Golay methods see Numerical Recipes in C: http://lib-www.lanl.gov/numerical/bookcpdf.html chapter 15

Function

Description

analysis >

analysis
(“X”, startRow, endRow)
Takes all columns named “X” and extracts startRow to endRow for each of those columns, appending the values into a single column.
dataSets
datasets(“X”)
Appends the dataset names of all datasets that have a column named “X”. Use analysis and datasets together to create a graph (analysis on the vertical axis and datasets on the horizontal). for example, if you had 3 datasets as follows:
DS1  DS2  DS3
X       X      Y
1      11     21
2      12     22and then added analysis(“X”, 1, 1) and datasets(“X”) you would get:

datasets    analysis
DS1             1
DS2            11


beats per minute

BeatsPerMinute(“Signal”, “Time”, intervalInSeconds, minPercent, maxPercent, noise)
Returns the number of beats per minute of the values in “Signal” vs. “Time”. This function is similar to the rate function except that the interval given here is always in seconds and the returned value is always in minutes. For example, if “Time” is in seconds then: beatsPerMinute(“Signal”, “Time”, interval, min, max, noise) = 60 * rate(“Signal”, “Time”, interval, min, max, noise)

blood pressure >

diastolic
The measured arterial pressure when the heart is at rest. “Pressure” and a “Time” column as inputs and return a single number.
diastolic(“Pressure”, “Time”)
“Pressure”: Pressure values from the BPS
“Time”: Time the pressure values were recorded
Returns the smaller number of blood pressure
meanArterialPressure
meanArterialPressure(“Pressure”, “Time”)

“Pressure”: Pressure values from the BPS
“Time”: Time the pressure values were recorded
Returns the pressure value at the max peak used for blood pressure calculations.

Oscillations
Oscillations(“Pressure”, “Time”)
“Pressure”: Pressure values from the BPS
“Time”: Time the pressure values were recorded
Returns the Oscillations of the peaks and valleys used to calculate systolic and other blood pressure values.
OscillatoryPeaks
OscillatoryPeaks(“Pressure”, “Time”)
“Pressure”: Pressure values from the BPS
“Time”: Time the pressure values were recorded
Returns the peaks used to calculate systolic, diastolic, and pulse (the “high” values in “Oscillations”).
pulse
pulse(“Pressure”, “Time”)
“Pressure”: Pressure values from the BPS
“Time”: Time the pressure values were recorded
Returns the pulse using the inputs from the Blood Pressure Sensor (similar results, different algorithm as the other beats-per-minute functions)
systolic
systolic(“Pressure”, “Time”)
“Pressure”: Pressure values from the BPS
“Time”: Time the pressure values were recorded
The measured arterial pressure when the heart contracts. Returns the larger number of blood pressure

boolean >

For the boolean functions a 1 is considered true, 0 false and anything else an invalid input
AND
AND(X, Y) return 1 if and only if X and Y are both 1
NOT
NOT(X) return 1 if X is 0; 0 if X is 1
OR
OR(X, Y) return 1 if X or Y is 1
XOR
XOR(X, Y) return 1 if X or Y is 1 but not both

calculus >

derivative
derivative(“Y”, “X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
The numerical derivative is the weighted average of the slope of ‘n’ points around each point. You can set ‘n’ in Settings for (Name). If you don’t supply an “X” column, the program will find one.
derivativeSG
derivativeSG(“Y”, “X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
Savitsky-Golay derivative. Fits a polynomial to ‘n’ points around each point and computes the derivative of the polynomial at that point. You can set ‘n’ in Settings for (Name). If you don’t supply an “X” column, the program will find one.
derivativeTimeShift
derivativeTimeShift(“Y”, “X”)
Returns the derivative of “Y” with respect to “X”.
This function is specifically designed to be used with photogate and picket fence data. The derivatives returned are adjusted to estimate values at the start of the timing interval, instead of the midpoint. For details see The Physics Teacher, Vol 35, April 1997, p. 220. The article written by William Leonard is entitled “The Dangers of Automated Data Analysis.”
Average velocity during the time interval is equal to the instantaneous velocity at midpoint of the time interval.
Where

integral
integral(“Y”,”X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
The numerical integral is the running sum of the areas of rectangles calculated by the midpoint rule. The i’th rectangle is (Yi – Y(i-1)) / (Xi – X(i-1)). If you don’t supply an “X” column, the program will find one.
secondderivative
secondDerivative(“Y”, “X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
Calculates the numerical second derivative of “Y” with respect to “X”. If you don’t supply an “X” column, the program will find one.
secondderivativeSG
secondDerivativeSG(“Y”, “X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
Savitsky-Golay second derivative. Fits a polynomial to ‘n’ points around each point and computes the second derivative of the polynomial at that point. You can set ‘n’ in Settings for (Name). If you don’t supply an “X” column, the program will find one.
secondderivative
Time Shift
secondDerivativeTimeShift(“Y”, “X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
Numerical time-shifted second derivative. Calculates the second numerical derivative of “Y” with respect to “X”. The values are shifted so that the derivatives are calculated at the midpoints between each two values. If you don’t supply an “X” column, the program will find one.

collapse

collapse(“X”)
Returns a column with all non-numerical cells (blanks and text) removed.

collapseIndirect

collapseIndirect(X, Y)
Returns a column of only the rows in “X” corresponding to rows in “Y” that have valid numerical cells.

constant

Constant(x, num)
x: A real number
num: A real number or a column
Generates a constant column filled with the value ‘x’.  The number of values in the returned column is num, or if a column was passed in, the size of the passed-in column.

delta

delta (“X”)
“X”: A column of real numbers
Returns a column of values where the i’th value is the i’th value in “X” minus the (i-1)’th value in “X”.

digital filtering >

lowPassFilter
(“Y”, “X”, “ripple”, “freqCutoff”)
“Y”: The data column to be filtered
“X”: The associated time column for “Y”
“ripple”: The ripple allowed in the pass-band
“freqCutoff”: Cut-off frequency (-3dB), in hertz
Applies a Chebyshev low-pass filter. For “ripple”, enter a value that is a percent of the pass-band. To apply a Butterworth low-pass filter, set “ripple” to 0.
highPassFilter
(“Y”, “X”, “ripple”, “freqCutoff”)
“Y”: The data column to be filtered
“X”: The associated time column for “Y”
“ripple”: The ripple allowed in the pass-band
“freqCutoff”: Cut-off frequency (-3dB), in hertz
Applies a Chebyshev high-pass filter. For “ripple”, enter a value that is a percent of the pass-band. To apply a Butterworth high-pass filter, set ripple to 0.
bandPassFliter
(“Y”, “X”, “lowFreq”, “highFreq”)
“Y”: The data column to be filtered
“X”: The associated time column for “Y”
“lowFreq”: Low frequency cut-off (-3dB), in hertz
“highFreq”: High frequency cut-off (-3dB), in hertz
Ripple is automatically set to zero and is not adjustable. The function returns the signal with the frequencies outside the designated frequency range removed.
bandStopFliter
(“Y”, “X”, “lowFreq”, “highFreq”)
“Y”: The data column to be filtered
“X”: The associated time column for “Y”
“lowFreq”: Low frequency cut-off (-3dB), in hertz
“highFreq”: High frequency cut-off (-3dB), in hertz
Ripple is automatically set to zero and is not adjustable. The function returns the signal with the frequencies inside the designated frequency range removed.
timeDecayFilter
(“Y”, “X”, “decayConstant”)
“Y”: The data column to be filtered
“X”: The associated time column for “Y”
“decayConstant”: A value in seconds that determines the decay of “Y”
Applies an exponential time decay to the signal.

ElectrophoresisInterpolate

ElectrophoresisInterpolate(“Std. Dist”, “Std. BP”, “Dist”)
“Std. Dist”: Distances from the standard
“Std. BP”: Base Pair Counts from the standard
“Dist”: Distances to interpolate
Returns a column of base pair counts based on the Electrophoresis curve fit for “Std. Dist” vs. “Std. BP” given “Dist”. Will NOT work if curve fit has been deleted. This function is used automatically when doing a Gel Analysis (Electrophoresis).

exp

exp(“X”)
“X”: A column of real numbers
Returns the exponent, exp(x) = e^x, where e is the natural log base (2.17…).

integer

integer(“X”)
Extracts the integral part of values in “X”.

interpolate

interpolate(“X”)
Fills in missing values using linear interpolation.

ln

ln(“X”)
“X”: A column of real numbers larger than 0
Returns the natural logarithm. If b = ln(a) then e^b = a  (Where e is the constant 2.17…).

log

log(“X”)
“X”: A column of real numbers larger than 0
(Log base 10) If b = log(a) then 10^b = a.

modulo

modulo(“X”, n)
“X”: A column of integers
n: An integer larger than 0
Returns the remainder of each of the numbers in “X” when divided by n.

photogate >

Blocked MidTimes
BlockedMidTimes(“Time”, “Gate1”, “Gate2”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Calculate the average times between blocked events from Gate 1 to Gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
Blocked to Blocked
BlockedToBlocked(“Time”, “Gate1”, “Gate2”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Returns a column of the times between successive blocked events in gate 1 and blocked events in gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
Blocked to Unblocked
BlockedToUnblocked(“Time”, “Gate1”, “Gate2”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Returns a column of the times between successive blocked events in gate 1 and unblocked events in gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
Blocked to Unblocked MidTimes
Blocked to Unblocked MidTimes
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Calculate the average time between the blocked events in gate 1 and unblocked events in gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
derivativeTimeShift
DerivativeTimeShift (“Y”, “X”)
Returns the derivative of “Y” with respect to “X”.
This function is specifically designed to be used with photogate and picket fence data. The derivatives returned are adjusted to estimate values at the start of the timing interval, instead of the midpoint. For details see The Physics Teacher, Vol 35, April 1997, p. 220.
Average velocity during the time interval is equal to the instantaneous velocity at midpoint of the time interval.
Where

Pendulum Period
PendulumPeriod(“Time”, “Gate1”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
Calculate the time between every other blocked event on Gate 1. If you don’t enter a “Time” column, the program will find one.
secondDerivativeTimeShift
secondDerivativeTimeShift(“Y”, “X”)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
Numerical time-shifted second derivative. Calculates the second numerical derivative of “Y” with respect to “X”. The values are shifted so that the derivatives are calculated at the midpoints between each two values. If you don’t supply an “X” column, the program will find one.
Unblocked to Blocked
UnblockedToBlocked(“Time”, “Gate1”, “Gate2”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Returns a column of the times between successive unblocked events in gate 1 and blocked events in gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
Unblocked to Unblocked
UnblockedToUnblocked(“Time”, “Gate1”, “Gate2”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Returns a column of the times between successive unblocked events in gate 1 and unblocked events in gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
Unblocked to Blocked MidTimes
Unblocked to Blocked MidTimes
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Calculate the average time between unblocked events in gate 1 and blocked events in gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.
Unblocked MidTimes
UnblockedMidTimes(“Time”, “Gate1”, “Gate2”)
“Time”: Optional. A column of real numbers (the times of events)
“Gate1”: A column of photogate states (1’s and 0’s)
“Gate2”: Optional. A column of photogate states (1’s and 0’s)
Calculate the average times between unblocked events from Gate 1 to Gate 2. If you don’t enter a “Time” column, the program will find one. If you don’t enter “Gate2”, “Gate1” will be used.

rate

rate(“Y”, “X”, t, m1, m2, n)
“Y”: A column of real numbers
“X”: Optional. A column of real numbers
t: Optional. Time interval
m1: Optional. Minimum threshold
m2: Optional. Maximum threshold
n: Optional. Noise threshold
Returns the rate of “Y” with respect to “X”, where t is the time interval measured, m1 is min percentage threshold, m2 is max percentage threshold, and n is noise threshold. “X”, t, m1, m2, and noise are all optional with default values “X” is time column, t = 1/10 the range, m1 = 40%, m2 = 60%, and noise = 0. Details

rotary motion >

amplitude
(“Data Column”, “Time Column”, “Min Percent”, “Max Percent”, “Time Interval”)
“Data Column”: Data for which you want to calculate amplitude
“Time Column”: Associated time column for “Data Column”
“Min Percent”: Threshold used to detect valleys
“Max Percent”: Threshold used to detect peaks
“Time Interval”: Period of time over which amplitude is calculated (in the time units of the experiment)
Calculates peak to peak amplitude. For Min and Max Percent, enter values between 0 and 100. Smaller values are more sensitive to noise and thus more sensitive to real cycles. Larger values are less sensitive to noise; too large of a value may filter out real cycles. “Time Interval” ends at the row at which the value is calculated (the current time).
period
(“Data Column”, “Time Column”, “Min Percent”, “Max Percent”, “Time Interval”)
“Data Column”: Data for which you want to calculate period
“Time Column”: Associated time column for “Data Column”
“Min Percent”: Threshold used to detect valleys
“Max Percent”: Threshold used to detect peaks
“Time Interval”: Period of time over which period is calculated (in the time units of the experiment)
Calculates the period of an oscillating function. For Min and Max Percent, enter values between 0 and 100. Smaller values are more sensitive to noise and thus more sensitive to real cycles. Larger values are less sensitive to noise; too large of a value may filter out real cycles. “Time Interval” ends at the row at which the value is calculated (the current time).

round

round(“X”)
“X”: A column of real numbers
Round. Returns the closest integer to x. If x is equidistant to two integers, round(x) gives the largest of the two (e.g., round(0.5) = 1).

smoothAve

smoothAve(“X”)
“X”: A column of real numbers
Returns a column of moving averages of the values in “X”. The width of the “window” to use when averaging points can be set in Settings for (Name)…

statistics >

abs
abs(“X”)
“X”: A column of real numbers
Absolute value. If x less than 0, then abs(x) = -x.  Otherwise, abs(x) = x.
ceiling
ceiling(“X”)
“X”: A column of real numbers
Returns the smallest integer larger than or equal to x.
floor
floor(“X”)
“X”: A column of real numbers
Returns the largest integer smaller than or equal to x.
max
max(“X”)
“X”: A column of real numbers
Compares all the values in a single column and returns a single number-the largest number in the column.
max2
max2(“X”, “Y”)
“X”: column of real numbers
“Y”: A column of real numbers or a single number.
Compares all the values in a column against a real number (e.g max2(“X”, 5.1))
mean
mean(“X”)
“X”: A column of real numbers
Arithmetic mean. Returns the sum of all the values in “X” divided by the number of values.
median
Median(“X”).
“X”: A column of real numbers
If m = median(“X”), then half the numbers in “X” are greater than (or equal) to m, and half are less than or equal.
min
min(“X”)
“X”: A column of real numbers
Compares all the values in a single column ,and returns a single number-the smallest number in the column.
min2
min(“X”, “Y”)
“X”: A column of real numbers
“Y”: A column of real numbers or a single number
Compares all the values in a column against a real number (e.g min2(“X”, 5.1))
numRows
NumRows(“X”)
“X”: A column of real numbers
Returns a single value-the number of rows in the column.
randInt
randInt(min, max, num):
min: A real number
max: A real number
num: A real number or a column
Random Integer. Returns a column of random integers between min and max (inclusive). The size of the returned column is num. If num is a column, then the size will be the number of rows in that column.
randReal
randReal(min, max, num)
min: A real number
max: A real number
num: A real number or a column
Random Real. Returns a column of random real numbers between min and max (inclusive). The size of the returned column is num. If num is a column, then the size will be the number of rows in that column.
stddev
stddev(“X”)
“X”: A column of real numbers
Standard Deviation. Returns a column representing the standard deviations of each of the numbers in a column.

step

step(start, increment, num, first, skip)
start: Start value
increment: Increment value
num: Number of values to generate
first: Optional. First non-empty row
skip: Optional. Rows to skip between each value
Generates a column “num” rows long starting with “start” and incrementing by “increment”. “num” can be a positive integer or a column name. Optional parameters: “first” is the first non-empty row and “skip” is the number of rows to skip between each value.

StepColumnBase

stepColumnBased(“X”, start, increment, first, skip)
start: Start value
increment: increment value
first: Optional. First non-empty row
skip: Optional. Row to skip between each value
Generates a column based on non-empty values in column “X” starting with “start” and incrementing by “increment.” “First” is the first non-empty row and “skip” is the number of rows to skip between each value.

subset

subset(“X”, startRow, step)
“X”: A column of real numbers
startRow: An integer larger than 0
step: An integer larger than 0
Extract a subset. Returns a column extracted from “X” starting with ‘startRow’ by ‘step’. For example, subset(“X”, 1, 2) will get every second row of “X” starting with row 1.

sum

Sum(“X”)
“X”: A column of real numbers
Returns a column whose n’th value is the sum of the values in “X” from row 1 to n.

sqrt

Square root. “X”: A column of non-negative real numbers.
If x is the square root of y, then x*x = y.

trigonometric >

sin
sin(“X”)
“X”: A column of real numbers
In a right triangle with angle between two sides ‘x’, sin(x) is the length of the opposite side divided by the hypotenuse.
cos
cos(“X”)
“X”: A column of real numbers
In a right triangle with angle between two sides ‘x’, cos(x) is the length of the adjacent side divided by the hypotenuse.
tan
tan(“X”)
“X”: A column of real numbers
In a right triangle with angle between two sides ‘x’, tan(x) is the length of the opposite side divided by the adjacent side.
asin
asin(“X”)
“X”: A column of real numbers between -1 and 1
Arcsine function. asin(x) = the angle whose sine is x.
acos
acos(“X”)
“X”: A column of real numbers between -1 and 1
Arccosine function. acos(x) = the angle whose cosine is x.
atan
atan(“X”)
“X”: A column of real numbers
Arctangent function. atan(x) = the angle whose tangent is x. The result will be between -pi/2 and pi/2.
sinh
sinh(“X”)
“X”: A column of real numbers
Hyperbolic sine.
cosh
cosh(“X”)
“X”: A column of real numbers
Hyperbolic cosine.
tanh
tanh(“X”)
“X”: A column of real numbers
Hyperbolic tangent.

Value

Value(n, “X”)
n: Number of rows backwards (when n < 0) or forwards (n >0) in column “X” to extract a value from.
“X”: Column from which to extract values .
Create a new column from another column by extracting offset values.

If data are imported from an experiment file, you may want to specify the independent column. For example, if the imported data included “time” in the first column but you wanted to calculate the derivative of pH with respect to volume, you have to define the derivative as derivative(“pH”,”Volume”).

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