Expression South Plugin

The foglamp-south-expression plugin is a plugin that is used to generate synthetic data using a mathematical expression to generate data that changes over time. The user may configure the plugin with an expression of their choice and define a period in terms of samples put period of the output and the increment between each sample.

expression_1

The parameters that can be configured are;

  • Asset Name: The name of the asset to be created inside FogLAMP.

  • Expression: The expression that should be evaluated to create the asset value, see below.

  • Minimum Value: The minimum value of x, where x is the value that sweeps over time.

  • Maximum Value: The maximum value of x, where x is the value that sweeps over time.

  • Step Value: The step in x for each call to the expression evaluation.

Expression Support

The foglamp-south-expression plugin makes use of the ExprTk library to do run time expression evaluation. This library provides a rich mathematical operator set, the most useful of these in the context of this plugin are;

  • Mathematical operators (+, -, *, /, %, ^)

  • Functions (min, max, avg, sum, abs, ceil, floor, round, roundn, exp, log, log10, logn, pow, root, sqrt, clamp, inrange, swap)

  • Trigonometry (sin, cos, tan, acos, asin, atan, atan2, cosh, cot, csc, sec, sinh, tanh, d2r, r2d, d2g, g2d, hyp)

See Also

foglamp-filter-ADM_LD_prediction - Filter to detect whether a large discharge is required for a centrifuge

foglamp-filter-expression - A FogLAMP processing filter plugin that applies a user define formula to the data as it passes through the filter

foglamp-filter-fft - A FogLAMP processing filter plugin that calculates a Fast Fourier Transform across sensor data

foglamp-filter-log - A FogLAMP filter that converts the readings data to a logarithmic scale. This is the example filter used in the plugin developers guide.

foglamp-filter-normalise - Normalise the timestamps of all readings that pass through the filter. This allows data collected at different rate or with skewed timestamps to be directly compared.

foglamp-filter-python35 - A FogLAMP processing filter that allows Python 3 code to be run on each sensor value.

foglamp-filter-rms - A FogLAMP processing filter plugin that calculates RMS value for sensor data

foglamp-filter-scale-set - A FogLAMP processing filter plugin that applies a set of sale factors to the data

foglamp-filter-specgram - FogLAMP filter to generate spectrogram images for vibration data

foglamp-filter-statistics - Generic statistics filter for FogLAMP data that supports the generation of mean, mode, median, minimum, maximum, standard deviation and variance.

foglamp-filter-vibration_features - A filter plugin that takes a stream of vibration data and generates a set of features that characterise that data