2
AR2700
User’s Manual
1.1
General Overview
The AR2700 is a time-of-flight rangefinder that measures distance using an infrared
(invisible) laser beam, a photodiode, and a microprocessor. The rangefinder works based
on comparative phase measurement by emitting modulated high-frequency light which is
diffusely reflected back from the target with a certain shift in phase. This return signal is
compared with a reference signal. From the amount of phase shift, a resulting distance is
determined with great accuracy. The maximum range measurement for the device is 885
feet (270 m) using special reflective targets. On normal surfaces with low reflectivity, the
maximum range is 230 feet (70 m). The Class 1 infrared laser diode makes the rangefinder
eye safe for use in all environments. The model is designed for fast measurement speeds,
up to 40 KHz, making it ideal for tracking the position of moving targets. Speed and
accuracy performances vary depending on target surface reflectance. The AR2700
technical data sheet specifies sensor performance standards.
A variety of configuration settings can be selected via the serial port. The complete list of
settings is found in the AR2700 Command Set chapter and each setting is discussed in
detail in a specific operation chapter.
The Sample Rate can be specified and the sensor has maximum capability of 40,000
samples per second. Sampling may be turned on and off. It can even be triggered using
an input signal wire or a serial command.
Measurement output can be in the form of serial data (RS232 or RS422) or Analog Output
(4-20mA current loop).
Do not attempt to disassemble the sensor or loosen any screws.
Improper
disassembly will destroy the optical alignment of the sensor and necessitate factory
repairs.
Do not operate the sensor in areas where the sensor case is exposed to direct
sunlight for extended periods or where the air temperature is more than 60
C (140
F)
or less than -20°C (-4°F)
.
Don’t allow fast temperature variations during sensor operation
.
Avoid excessive vibration and shocks
. The sensor contains securely mounted but
precisely aligned optical components.
Do not operate the sensor if the lens is fogged or dirty
.
Do not scratch the lenses on the front face of the sensor.
Keep the lenses clean with
expert optical procedures. The lenses are glass with an anti-reflection coating. Avoid the
use of organic cleaning solvents.
Do not touch the lenses with bare fingers
. The oils are very difficult to remove.
Operate only with DC supply voltages up to 30 volts.
1.2
Definition of Terms
Sensor
– The complete AR2700 measurement device.
Target
– The object of measurement. The relative distance from the sensor to the target
is measured by the sensor.
Laser, Laser beam
– This bright light is emitted from the sensor, reflected from the target,
and collected by the camera lens. For the AR2700, it is infrared radiation.
<Range>
– The maximum relative distance measurable by the sensor.
