Hyst 3

Type Function module

Input IN	REAL (input value)
HYST	REAL (width of hysteresis)
VAL1	REAL (mean of the hysteresis 1)
VAL2	REAL (mean of the hysteresis 2)
Output Q1	BOOL (Output 1)
Q2	BOOL (Output 2)
	HYST_3 is a three-point controller. The three-point controller consists of two hysteresis. Q1 is a hysteresis with val1 as the threshold and HYST as hysteresis. Q1 is TRUE when IN is less than VAL1 - HYST / 2 and FALSE when IN is greater than VAL1 + HYST / 2 . Q2 is analogous to val2. The three-point controller is used at all when motorized valves are controlled, which then be controlled with Q1r fo on and Q2 for off. If the value of IN between val1 and val2 both outputs are FALSE and the engine still stops.
Following Example shows the waveform of a 3-point controller