5.46. TAB2

Purpose

Generates a time dependent numerical value which can be used by other components.

Procedure

The TAB2 component can be used to operate a hydraulic component (e.g.: start/stop of a pump, open/close a valve). The time in the ‘action table’ is relative to the instant at which the input signal becomes TRUE(=1). This holds for the TRUE control ‘action table’. If the input signal becomes FALSE (=0), the second ‘action table’ will be used to generate output values. The TAB2 component takes care that the transition from TRUE to FALSE is continuous (the current output value will be the starting point in the second table). The two ‘action tables’ allows the TAB2 component to be bi-directional. The start value of the first table must correspond with the end value of the second table and vice versa. The tables should be monotoniously decreasing and increasing or vice versa.

Parameters

Parameter	input	unit	range	default	remarks
Table type	Valvepos/ pumptsp/ boundhth/ boundqtq/ CtrlActn			CtrlAcnt	This type is not used anymore; type will be ignored
Action table (true)	table				start value = end value of Action table (false);
Action table (false)	table				start value = end value of Action table (true)

Remarks

If no logical signal line is connected to the input channel a value of TRUE is assumed. In such a case the TAB2 component is similar to a standard action table.

Examples

The table below presents the TRUE and FALSE ‘action tables’ for the TAB2 component with respectively the non-linear opening and closing control of a valve. Figure 2a presents its output and input signals. The green line is the logical input signal, while the red line is the numerical output signal.

True table used for VALVE opening		False table used for VALVE closing
Time	SI_quantity (-)		Time	SI_quantity (-)
0.0	0		0.0	1
8.0	0.2		2.0	0.2
10.0	1.0		10.0	0.0

Fig. 5.46.1 Control output

Fig. 5.46.2 Valve position