Honeywell VRX180 User Manual Download

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Programming Function Blocks and Features

Video Recorder – User Manual

Table 4-6 Standard Algorithm Prompts

(continued)

Prompt

Range/Selections

Definition

TEMPERATURE UNIT

Select C for Degrees Celsius, F for
Degrees Fahrenheit, K for Kelvin, R for
Rankine, or NONE.

Specifies the temperature units used for
thermocouple, pyrometer, and RTD input
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,
pyrometer, or RTD inputs. Select INDIR
(Indirect) for volt or millivolt signal inputs
from linear or non-linear transmitters.
Select SQRT (Square Root) for extracting
flow measurements from a voltage input
representing differential pressure
measurements. If SQRT is chosen, the
RANGE LOW and RANGE HIGH must be
adjusted to specify the upper and lower
limits of the flow units span.

Note that the term “direct” generally applies to
input types where the sensors in direct
physical contact with the monitored process
are also in direct physical contact with the
instrument terminal board. The term “indirect”
applies to inputs from transmitters since the
sensors in direct physical contact with the
monitored process are indirectly connected to
the instrument through the transmitter circuitry
and wiring.

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 HIGH values specified are in
units of VOLTS, MV (millivolts), or OHMS.

Circuit low and circuit high units.

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),
Downscale (DOWN) or None.

Determines whether or not failsafe is active
and, if so, which direction.

CLAMPING

HI RANGE clamps the input at the
RANGE HIGH value. LO RANGE clamps
input at the RANGE LOW value. RANGE
clamps input over both the low and high
range values. NONE gives no clamping.

Clamps input at specified value.

ATTENTION

: Clamping is not recommended

for process variable inputs to control loops.