AR4000 User’s Manual
6
LLL004001 – Rev 2.7
Line 3: Heater Power, 5 to 7 volts at 0-2 amperes, temperature dependent.
Color: Orange
Heater power and return may be optionally connected to supply power for
temperature regulation within the sensor. The current drawn by the heater power
circuitry depends on the difference between the ambient temperature and the hold
temperature for which the sensor is configured. It may be as high as 2 amperes in
extreme cases. The sensor power and ground lines should only be connected to
the heater power and ground at the source of a low impedance power supply, to
prevent high heater current from causing significant voltage drops in the supply
lines for the sensor electronics. This line should be left disconnected if heater
power is not used.
Line 4: Heater Power Return
Color: Brown
Return for the optional heater power. If heater power is used, connect to the
sensor electronics ground at the power supply. This line should be left
disconnected if heater power is not used.
Line 5: Temperature output: 0 to 4 volts. 5 mA max.
Color: Yellow
The temperature output is a linear indication of internal sensor temperature. This
may be used to monitor the internal temperature and to make range corrections
due to changes in temperature, although the temperature dependence of the
indicated range is typically small. The temperature output will change
approximately 29 millivolts for each 1
°
F change in sensor temperature, and
should read about 2.5 volts when the sensor is at 85
°
F. This output should be left
open when not in use.
Line 6: Pulse Width Range Signal: Pulse width square wave
OR: Optional Current Loop Range Output: 4-20 milliamps, 10 V max
output
Color: Blue
In the standard AccuRange 4000 configuration, this output provides an
uncalibrated measure of range. The period of the pulse is the sample interval for
which the sensor has been configured with the Sample Rate command. The
duration of the low portion of the pulse is proportional to measured range, scaled
by the sample rate and maximum range for which the sensor is configured. The
appearance is that of a square wave signal. See the Current Loop and Pulse
Width Outputs section for details. The pulse width signal is used by the
AccuRange High-Speed Interface to make range measurements at high sample
rates. It may be timed by sampling hardware to determine indicated
(uncalibrated) range.
You need a 50 Ohms (51 Ohms +/-5% ok) between Signal
(blue) and Ground Reference (black). If you don’t have this resistor, the voltage
goes up and you see saw-tooth shape on the signal.
If the sensor was ordered with the optional current loop output, this line will
deliver a current proportional to the measured range. The zero range current,
offset of the zero range point, and the span (point of full scale output) may be set
using the appropriate commands. If calibrated output mode is enabled, the output
will be the actual distance to the target. Otherwise, the output will be the raw
sensor range, uncompensated for temperature, signal strength, and other effects.
