A Curve object interpolates in a table specified by a
Table object.
The table has to consist of at least 2 of up to 50
possible pairs of numbers (x,y).
The x-values have to be arranged in an increasing
order. At step functions two consecutive x-values are
always equal.
Several Curve objects can be connected to one and the
same Table object.
The object contains only data without any executable
code.
Examples
Example 1
Assume a valve with a strong non-linear characteristic
between control signal and flow. To improve the performance
at a wide operational range it is possible to let the control
signal from a Pid object pass a Curve object before it feeds
the actuator. The Table object is to realize a characteristic
inverse to that of the valve.
Example 2
Positioning forward/backward + analog reference to specify
the speed. Positional error greater than 10 will result in
a maximum speed of 100. Positional error less than 2 will give
a minimum speed of 10. Positional error between 2 and 10 gives
linear speed in the interval 10 and 100.
The positional error ( position - set value) is connected to a
Curve object. A Table object with 4 pairs of numbers is needed:
X1 = -10 Y1 = 100 X2 = -2 Y2 = 10
X3 = 2 Y3 = 10 X4 = 10 Y4 = 100
Example 3
Square signal.
The output has to be connected to a Curve object.
TabVect[0]
Specifies the current number of pairs of numbers in the
table.
TabVect[1], TabVect[2]
The initial pair of numbers {x1, y1}
TabVect[3], TabVect[4]
The second pair of numbers {x2, y2}
