5.9. COND

Purpose

Compares the value from the input channel with a set value.

Procedure

The (measured) value at the input channel is compared with the set value. The type of comparison is chosen by the ‘Logical operator’.

Parameters

Parameter	input	unit	range	default	remarks
Logical operator	LT (less than)/ GT (greater than)/ LE (less equal)/ GE (greater equal)/ EQ (equal)/ NE (not equal)
Set value	real
Reset time (true)	real	[s]		0
Reset time (false)	real	[s]		0

Remarks

The condition must hold for a period longer than the ‘reset time’ before the output will switch its original value. If the condition does not hold for a period longer than the ‘reset time’ then the output will keep its original value and the timing period will be restarted.

Examples

Fig. 5.9.1 Control scheme

Figures Fig. 5.9.2 and Fig. 5.9.3 show the output when both ‘reset times’ are not used (0 seconds).

Fig. 5.9.2 variation of Head measured by Sensor

Fig. 5.9.3 Output of COND and LTAB

Figure Fig. 5.9.4 shows the output when ‘reset time (true)’ is set to 5 seconds and ‘reset time (false)’ is set to 2 seconds.

Fig. 5.9.4 Output of COND including reset times (true =5 s, false = 2s)