Practical Instrument Electronics 830 - Manual (Page 17)

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MODE OFF LINEAR NONLINEAR SQ ROOT
BURNOUT DOWN UP
LOOPSCOPE OFF ON
MODE - pressing the knob will cycle through OFF, LINEAR,
NONLINEAR. When setup to read pressure SQ ROOT replaces
NONLINEAR.
LINEAR turns on the mA display and regulates the loop
current linear with the input signal. For thermocouples &
RTDs this is linear relative to the temperature between zero
and span of the sensor input. This mimics the operation of a
digital temperature transmitter or other linearizing transmitters.
NONLINEAR (applies only to thermocouples and RTDs)
turns on the mA display and regulates the loop current linear
with base units (millivolts or ohms) of zero and span of the
sensor input. This mimics the operation of an analog
temperature transmitter without linearizing.
SQ ROOT turns on the mA display and regulates the loop
current with square root extraction of zero and span of the
pressure module input. This mimics the operation of a
differential pressure transmitter setup for square root extraction.
BURNOUT selects the failure mode of the calibrator when the
input signal is lost or beyond the input scale.
Down sets the output
to 1.0 mA and UP to 21.5 mA when sensor failure is detected.
LOOPSCOPE turns on the Loop Diagnostic display which
simultaneously indicates the current, voltage and resistance
of the loop. When enabled the
LOOPSCOPE also indicates
errors by flashing the LED and writing diagnostic messages
on the display. Messages include
LOW LOOP VOLT, HIGH
LOOP VOLT and HIGH LOOP IMPED. With LOOPSCOPE on
the 830 occasionally performs a test on the loop. During this
short test the loop mA signal will be affected.