Honeywell VRX180 user manual Compare Prompts

Programming Function Blocks and Features

Compare

Compare can be used instead of an Alarm’s output to control a relay. It can also provide on/off control with hysteresis.

Compares 2 inputs. Call the result of this comparison “Result”. Result is a pulse that goes ON(1) when comparison is true, and OFF(0) when comparison is not true. If hysteresis is given a value, then Result will not go OFF(0) until hysteresis value is exceeded. Result is then processed according to the specified condition type and condition time. The final output is a discrete pulse CVn OS.

Input #1	COMPARE		CONDITION
Input #2	OPERATOR	Result	TYPE	CVn OS
			&
	&		CONDITION
	HYSTERESIS
			TIME

Figure 4-2 Compare Signal Flow

Table 4-19 and Table 4-20 describe the Compare prompts. See Table 4-2 for additional prompts.

Table 4-19 Compare Prompts

Prompt	Range/Selections		Definition
INPUT #1	OFF, analog parameter,	Input sources to be compared.
INPUT #2	number
OPERATOR	EQ, GT, LT, GTE, LTE, NEQ	The Result will be set to ON(1) when the comparison is true:
		Input #1 OPERATOR Input #2
		where OPERATOR is:
		EQ(=), GT(>), LT(<), GTE (≥ ), LTE (≤ ), NEQ(≠ )
		The Result will be set to OFF(0) when the comparison is false.
HYSTERESIS	Number, OFF	Applies to all operators except EQ and NEQ. If given a value,
		hysteresis determines when Result goes OFF(0) after the
		comparison becomes false.
		Operator	Hysteresis Function
		GT:	Result goes OFF when Input #2 - Input #1 ≥ Hyst
		GTE:	Result goes OFF when Input #2 - Input #1 > Hyst
		LT:	Result goes OFF when Input #1 - Input #2 ≥ Hyst
		LTE:	Result goes OFF when Input #1 - Input #2 > Hyst
		See Figure 4-3.
CONDITION TYPE	NONE, DELAY, EXTEND,	See Table 4-20.
	PULSE, RT PULSE
CONDITION TIME	OFF or number	Enter number of seconds of condition time. See Table 4-20.

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