Honeywell VRX180 user manual Temperature Unit

Programming Function Blocks and Features

Table 4-6 Standard Algorithm Prompts (continued)

Prompt		Range/Selections		Definition
TEMPERATURE UNIT		Select C for Degrees Celsius, F for		Specifies the temperature units used for
		Degrees Fahrenheit, K for Kelvin, R for		thermocouple, pyrometer, and RTD input
		Rankine, or NONE.		types. The default setting is F. If you change
				the default, be sure to change the analog
				input’s RANGE LOW and RANGE HIGH
				values accordingly. The instrument will not
				adjust these values by itself.
				Ignore the TEMPERATURE UNIT prompt or
				set it to NONE, if the analog input being
				programmed will not be used for temperature
				measurements.
DIRECT/INDIRECT	Select DIRECT for thermocouple,			Note that the term “direct” generally applies to
		pyrometer, or RTD inputs. Select INDIR		input types where the sensors in direct
		(Indirect) for volt or millivolt signal inputs		physical contact with the monitored process
		from linear or non-linear transmitters.		are also in direct physical contact with the
		Select SQRT (Square Root) for extracting		instrument terminal board. The term “indirect”
		flow measurements from a voltage input		applies to inputs from transmitters since the
		representing differential pressure		sensors in direct physical contact with the
		measurements. If SQRT is chosen, the		monitored process are indirectly connected to
		RANGE LOW and RANGE HIGH must be		the instrument through the transmitter circuitry
		adjusted to specify the upper and lower		and wiring.
		limits of the flow units span.
CIRCUIT LOW	OFF or number		Appears only if “INDIR” or “SQRT” was
				previously selected. Is the actual low end
				value of voltage to be used for Indirect
				measurements.
CIRCUIT HIGH	OFF or number		Appears only if “INDIR” or “SQRT” was
				previously selected. Is the actual high end
				value of voltage to be used for Indirect
				measurements.
ELECTRICAL UNITS	Select whether the CIRCUIT LOW or			Circuit low and circuit high units.
		CIRCUIT HIGH values specified are in
		units of VOLTS, MV (millivolts), or OHMS.
LAG		≥ 0 seconds or OFF		“LAG” is a time constant applied to the input
				measurement value. This provides digital
				filtering (LAG) to the measurement.
				Lag appears on menu only if EXPANDED
				INPUT is enabled under Enable Features in
				the Program menu.
SAMPLE HOLD	OFF, discrete parameter, 0, 1		Holds Input. The input value is measured
				normally when this discrete is OFF and holds
				its last value when the discrete is ON(1).
				Hold appears on menu only if EXPANDED
				INPUT is enabled under Enable Features in
				the Program menu.
FAILSAFE	For thermocouples only, Upscale (UP),			Determines whether or not failsafe is active
		Downscale (DOWN) or None.		and, if so, which direction.
CLAMPING	HI RANGE clamps the input at the			Clamps input at specified value.
		RANGE HIGH value. LO RANGE clamps
		input at the RANGE LOW value. RANGE		ATTENTION: Clamping is not recommended
		clamps input over both the low and high		for process variable inputs to control loops.
		range values. NONE gives no clamping.

88 Video Recorder – User Manual