# Artisan Documentation

## Visual scope for coffee roasters

## Math Plotter (V 0.5.0)

The math plotter is a tool to look for mathematical patterns in profiles. The math plotter can superimpose up to 6 curves in the graph area. The curves are built from mathematical expressions.

Say that you open a profile and you want to find out what mathematical expression approximates the BT curve. Most profiles are natural decays that are based on the mathematical Ln() function (natural logarithm). So you could start by writing this expression in one of the six boxes.

If you are in Centigrade mode :

45*log(x,e)-60

If you are using Fahrenheit mode:

85*log(x,e)-120

Now you could change numbers till you find a curve that matches either ET or BT .

You can comment out an expression by putting a # in from of the expression. Next time you plot, the curve will not show up, but the expression will be there. That allows you to keep a collections of expression without deleting them. Expressions are stored in memory.

You can also refer to the ET and BT curves by using the same convention used in extra devices. For example, if your expression has Y1 in it (ET), then each of the values of ET will be extracted and used in the computation. For example, if you type Y1 + 20, you should see a parallel new curve just above ET.

This symbolic reference could be used for example to discover the calibration of sensors. With the new device HHM28 (a multimeter) introduced, sensors of any type can be attached. If you were to record a sensor, you may need to calibrate its output in the software side. This could be initially accomplished with the help of the plotter. For example, once you have collected the data from your sensor, you could plot it through an expression till you find the expression you want. Then you could take the same expression and paste it over to the extra devices expression (but changing for example Y2 for the variable x). From then on, you would have a calibrated output sensor.

**Supported math functions:**

- abs(x) – Return the absolute value of x.
- acos(x) – Return the arc cosine (measured in radians) of x.
- asin(x) – Return the arc sine (measured in radians) of x.
- atan(x) – Return the arc tangent (measured in radians) of x.
- atan2(y, x) – Return the arc tangent (measured in radians) of y/x.

Unlike atan(y/x), the signs of both x and y are considered. - cos(x) – Return the cosine of x (measured in radians).
- degrees(x) – Convert angle x from radians to degrees.
- exp(x) – Return e raised to the power of x.
- log(x[, base]) – Return the logarithm of x to the given base.

If the base not specified, returns the natural logarithm (base e) of x. - log10(x) – Return the base 10 logarithm of x.
- pow(x, y) – Return x**y (x to the power of y).
- radians(x) – Convert angle x from degrees to radians.
- sin(x) – Return the sine of x (measured in radians).
- sqrt(x) – Return the square root of x.
- tan(x) – Return the tangent of x (measured in radians).

Tags: Plotter