SYMBOLIC VARIABLES
Symbol Description Can shift?
(see below)
t Absolute time (seconds) from begin of recording (not only the time after CHARGE!) Yes
b Absolute time (seconds) from begin of recording of the background profile Yes
x Current channel reading (not available in the Plotter)  
Y1 ET value Yes
Y2 BT value Yes
Y3 Extra #1 T1 value Yes
Y4 Extra #1 T2 value Yes
Y5 Extra #2 T1 value Yes
Y6 Extra #2 T2 value Yes
... ...and so forth Yes
B1 ET background Yes
B2 BT background Yes
B3 ExtraBackground #1-A Yes
B4 ExtraBackground #1-B Yes
B5 ExtraBackground #2-A Yes
... ...and so forth Yes
T1 ET tare value  
T2 BT tare value  
T3 Extra Device #1 channel 1 tare value  
T4 Extra Device #1 channel 2 tare value  
T5 Extra Device #2 channel 1 tare value  
... ...and so forth  
E1 Last event value of the first event type  
E2 Last event value of the second event type  
E3 Last event value of the third event type  
E4 Last event value of the fourth event type  
     
R1 ET rate of rise Yes
R2 BT rate of rise Yes
RB1 Background ET rate of rise Yes
RB2 Background BT rate of rise Yes


SHIFTED SYMBOLIC VARIABLES
The symbolic variables t, b, Y<n>, B<n> and R<n> evaluate to the current value of a sequence of values that define a roast profile. To access earlier or later values one can apply a shift value.

For example, while "Y2" returns the current bean temperature (BT), "Y2[-1]" returns the previous BT temperature and "Y2[-2]" the one before that. Formulas used in the Plotter are applied in sequence to all values, thus there "Y2" points to the current BT temperature processed, "Y2[-1]" the previous BT temperature processed and "Y2[+1]" the next BT temperature to be processed. A positive shift is only available in the Plotter, obviously not during recording.
Example Description
t[+1] Time one index ahead (plotter only)
t[-3] Time three indexes delayed
Y1[-2] ET value delayed by 2 indexes
Y2[+1] BT value index advanced by one index (plotter only)
B4[-6] ExtraBackground #1-B delayed 6 indexes
B5[+2] ExtraBackground #2-A advanced 2 indexes (plotter only)
R1[-2] ET rate of rise delayed two indexes


INDEXED SYMBOLIC VARIABLES
Symbol Description
t, b, Y<n>, B<n> and R<n> Previously recorded data assigned to the symbolic variables t, b, Y<n>, B<n> and R<n> can also directly accessed by index. "Y2{0}" evaluates to the first recorded bean temperature (BT) and "Y2{CHARGE}" to the bean temperature at CHARGE. Additionally, the symbolic variable b can be used to access the recording time at a certain index of the background profile. Thus "b{CHARGE}" returns the recording time at CHARGE of the background profile.


AXIS MAPPING
Symbol Description
k Scaling factor from time to RoR axis. The range of the temperature scale divided by the range of the delta scale.
o Offset from time to RoR axis.
Note: RoR values r can be scaled to the temperature axis using a linear approximation of the form "r*k + o". As the variables k and o depend on the actual axis settings which can be changed by the user without triggering a recomputation, those variable are less useful for use in a recording, but useful in the Plotter to plot w.r.t. the RoR y-axis instead of the temperature y-axis.


EVENT INDEX and TIME DELTA
Symbol Description
CHARGE, DRY, FCs, FCe, SCs, SCe, DROP Index of the corresponding event of the profile to retrieve time and values from the corresponding data structures. Evaluates to -1 if not set.
bCHARGE, bDRY, bFCs, bFCe, bSCs, bSCe, bDROP Index of the corresponding event of the background profile to retrieve time and values from the corresponding data structures. Evaluates to -1 if not set.
   
dCHARGE, dDRY, dFCs, dFCe, dSCs, dSCe, dDROP Time distance in seconds after the corresponding event. Thus dCHARGE is bound to the current roast time (after CHARGE) in seconds while t is bound to the time in seconds from the start of the recording.


AREA UNDER THE CURVE (AUC)
Symbol Description
AUCbase AUC base temperature (could be from the selected event, if set)
AUCtarget AUC target value (could be from the background profile, if set)
AUCvalue the current AUC value. -1 if none available.


PREDICITONS
Symbol Description
pDRY Prediction of the time distance to the DRY event based on the current RoR. Evaluates to -1 on negative RoR and to 0 if the DRY event is already set.
pFCs Same as pDRY, just for the FCs event.
Note: The same rules as for the corresponding PhasesLCDs apply to pDRY and pFCs:

If there is no background profile the DRY or FCs bean temperature used for the prediction is taken from the Config>Phases setup.

If there is a background profile and there is DRY or FCs event in the background profile, the DRY or FCs bean temperature used for the prediction is taken from the background profile.

Exception to the above for DRY only: if AutoDRY is checked the DRY temperature used for the prediction is taken from the Config>Phases setup. This does not apply to FCs and AutoFCS.

The prediction value is the calculated time in seconds to reach the DRY or FCs temperature.


AMBIENT
Symbol Description
aTMP ambient temperature (default 0)
aHUM ambient humidity (default 0)
aPRE ambient pressure (default 0)
Note: The data is (re-)sampled some seconds after the start of recording


EXPRESSIONS
Expression Description
(<true-expr> if <cond> else <false-expr>) Conditional. Evaluates to the value of the expression <true-expr> if the condition <cond> holds, otherwise to the value of the expression <false-expr>. The rules of Python are applied to decide if a value holds or not. Thus the boolean values "True" and "False" have the obvious semantic. Any number unequal to 0 evaluates to True and 0 evaluates to False. The value "None" is also evaluated to False.


MATHEMATICAL FORMULAS
Formula Description
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.
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.
min(x1,...,xn) Return the minimum of the given values.
max(x1,...,xn) Return the maximum of the given values.
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).


MATHEMATICAL CONSTANTS
Symbol Value
e 2.71828182845904
pi 3.14159265358979


PLOTTER EXTENSIONS
Note: This section applies only to the Plotter
Using math formulas in the plotter also allows to use the symbolic variables P and F (see Signals, Symbolic Assignments and the Plotter).
Symbol Description
P1...P9 The variables P1,..,P9 represent the results from plot #1,..,#9. You can perform calculations in a later plot on variables of an earlier plot. That way, the plot variables P1,..,P9 allow the cascading or intermediate results. For example, plot #3 can refer to the results of plot 1 using the variable P1.
F1...F9 F1 refers to the previous result of the actual formula to realize a feedback loop. This is useful in filter designs. Similarly, F2 refers to the second previous result etc.