Acuity AR1000 Laser Distance…

Acuity AR1000 Laser Distance Sensor

The AR1000 laser distance sensor is ideal for crane and hoist applications or for monitoring fill levels of bulk material. The unique sensor uses phase shift comparison measurement principles (of light) to accurately measure distances of 30 meters. Longer ranges to 150 meters are possible with the use of reflective target boards (3M Scotchlite 3279).

Typical speeds for the AR1000 laser distance sensor are 6 Hz, but 50 Hz sampling can be realized at close ranges with small target movements.


The AR1000 laser distance sensor is ideal for crane and hoist applications or for monitoring fill levels of bulk material. The unique sensor uses phase shift comparison measurement principles (of light) to accurately measure distances of 30 meters. Longer ranges to 150 meters are possible with the use of reflective target boards (3M Scotchlite 3279).

Typical speeds for the AR1000 laser distance sensor are 6 Hz, but 50 Hz sampling can be realized at close ranges with small target movements.

The sensor is designed for industrial environments with NEMA-4, IP67 enclosure ratings, permitting the sensor to be directly rinsed with water! Typical data outputs are serial RS232, RS422 (optional) and current loop 4-20 mA signals.

This sensor is highly versalite, able to measure distances both indoors and outdoors, but may have limitations to extremely dark targets or measuring through steam, fog and smoke where the signal is obstructed.

A special AR1000H version is available with an internal heater, making the sensor suitable for operation to -40°C (-40°F). Users can configure the cycling of the heater through the serial interface.

Theory of Operations:

Acuity’s AccuRange 1000 laser distance sensors are very unique distance measuring devices. They employ a phase-shfit comparison measurement principle that leads to very accurate distance calculations. The LIDAR technology uses high frequency amplitude modulation with continuous wave laserdiodes. The AR1000 measures the phase shift of up to five frequencies of emitted light to accurately gage the distance to a target.

The AR1000 measures from 0.1 to 30 m (~100 feet) without the use of reflective targets. It can measure to any opaque surface. The accuracy of the measurement is typically +/-2.5 mm, but it will depend on the reflectivity of the target surface, lighting conditions and temperature conditions. Dark-colored targets may be less accurate targets than light-colored targets. In simple sampling modes, the AR1000 self-determines the optimal sampling speed. Typical sampling output rates are 6 Hz. 50 Hz sampling is possible at close ranges to white targets. See the technical document download area for more information.

For very distant measurements, one can use reflective target material (3M Scotchlite 3279) to measure between 30 and 150 meters (500 feet). The AR1000 has a Class 2 visible laser diode for simple aiming and setup. The laser beam spot size is 5 mm with a divergence of 0.6 milliradians. Therefore, large targets may be necessary at very long distances.

This measurement sensor comes standard with a RS232 serial interface for communication with a PC computer or PLC. Also standard is a 4-20 mA current loop output and a single Limit switch for indicating alarms. The linearity of the analog output is +/- 0.15% of the span. This can be useful for triggering an external device when a target reaches a set position. The AR1000 can automatically sample distances or receive an external trigger for a single distance measurement. As an option, the AR1000 can be ordered with RS422 (replaces RS232).

A special AR1000H version of this device can be used from -40°C to 50°C thanks to an internal heater that automatically cylces on and off based on the user’s configured settings.

The sensor is also standard with a 2 meter (6 ft.) cable with Binder series 723 flange connector and soldertail wire termination. Users design their own connectors suitable for their application requirements.

The AR1000 has several measurement modes that are optimized for speed, accuracy, long distances or short distances.Consult the User’s Manual for a description of these modes.


Acuity offers the following standard and optional outputs for the AR4000 laser rangefinder devices:

Standard RS-232 Serial Output

All sensors come with an RS-232 serial output on the 2m (6 foot), 9 pin cable that connects to PC style serial ports after the user attaches a DB9 connector. Serial output is ASCII and may be configured as either decimal or hexadecimal. The maximum baud rate is 38400 baud.

Standard RS-422 Serial Output

For long distance communications (more than 20 to 30 feet, depending on the baud rate), the RS-232 serial output may be replaced with an RS-422 serial output. The available sample rates, formats and software configuration commands are all the same as for the RS-232. Acuity recommends an RS422 to RS232 converter to monitor the interface from a PC computer serial port.

Standard Current Loop Output                      

A 4-20 milliamp current output is a standard output for the AR1000 laser distance sensor. The zero and span for the current loop output may be set at any location.. The span point (20 mA) may be made closer than the zero point if desired. The 4-20 mA output has a maximum voltage capability of 10 volts, and it is suggested that a 400 to 500 ohm load be used at the reading instrumentation for best accuracy.

Product Applications:

The AR1000 laser rangefinders are versatile sensors used to measure long distances with great accuracy, but at slower speeds. The device’s compact design allow it to be placed in very tight spaces.

Dusty applicaitons may require the use of a dust tube extended around the optical areas of the sensor. Heaters or coolers may also be necessary to stabilize the temperature to within the suggested working range. This Acuity product has been adopted in many applications and markets including the forest products industry, crane and hoist applications, paper production and grain silo monitoring. The unit can be placed in an explosion-proof enclosure that is supplied by the cutomer.

Crane Positioning:

Bridge Cranes


Accurate distance measurements for bridge cranes in busy seaports

Monitoring the position of trollies and hoists on bridge cranes in busy seaports requires accurate distance measurements afforded by the AR1000 laser distance sensor. Laser distance meters often replace damaged encoders. The position is continually monitored for crash-avoidance and for automated retrieval systems.


Hoist / Crane Application On A Palletizer


Laser rangefinders verify the positions of palettes

A major frozen dough manufacturer automates much of their production and packaging. They use a palletizer to organize cases of product onto a pallet. This robotic machine builds each row of boxes and the position of the moving parts is verified with a laser rangefinder. The sensors report positional feedback to a master PLC so that no boxes are crushed or improperly positioned.

The solution was implemented by a local integrator who chose the eye-safe AR4000-RET rangefinders which had a high frequency response and an analog output 4-20mA signal. The sensors operate in cold ambient temperatures and are impervious to the electromagnetic interference created by the robot’s variable frequency drive motors.



Height Measurement


Laser measurement sensors are often used for height measurement

This broad category encompasses a variety of non-contact application where laser sensors are used to measure the height of targets that pass beneath a stationary sensor.


Dam Height Measurement


Long-distance rangefinders from Acuity are ideal for remote dam height measurement

Acuity laser rangefinders are used to measure the height and position of a remote dam at a hydroelectric facility. Long-distance rangefinders are better than other sensors which may wear over time or require installation in the elements. Laser rangefinders may be remotely installed inside a control cabin or inside a protective housing, away from direct sunlight and corrosive humidity.

dam being monitored by a laser rangefinderdam height measurement with laser sensors


Elevator Position Measurement


Laser sensors measure the position of elevators between floors

The design integrators for the Minneapolis Public Library selected Acuity laser rangefinders to monitor the position of their elevators. The laser rangefinders were installed in base of the elevator shaft and aimed upward to a target affixed to the bottom of the elevator cart.


Height Of Flux In Flux Core Weld Wire


Lasers measure the fill height of flux in the wire

A manufacturer of flux-core weld wire uses laser measurement sensors to measure the fill height of flux in a channeled wire.

laser sensors measuring the height of flux core


Human Height Measuring


A laser can be affixed to the ceiling, measuring anyone who passes beneath

Science museums hosting interactive exhibits that measure human height use Acuity AR1000 laser distance sensors to automatically measure a person’s height. The sensor is affixed to the ceiling and aimed to the floor. When a person stands beneath the laser’s path, their high is automatically displayed.

Livestock Measurement


Laser sensors measure cow hip height from overhead

Acuity laser rangefinders have been adopted in the cattle industry. As a means of automating the measurements of growing cows in feedyards, a major beef technologies company from Texas decided to use non-contact measurement principles.

Historically, in determining how long to feed the cattle and when to market them, the feedyard manager subjectively evaluated an entire pen of cattle at a time. When a group or “lot” of cattle first arrived at the feedyard, the manager went out to their pen and looked at or “eyeballed” those cattle and made a guess at how long he should feed them. Today, using the AR4000-LV laser rangefinder or the AR1000 distance measurement sensor, the feedmanager can collect metrics for each cow by measuring “hip height”, a major indicator for the size of the cow.

The engineers position the AR4000-LV laser rangefinder from the ceiling supports and aim the laser spot down to the floor. The sensor is “zeroed” and when a cow passes underneath the laser sensor, the system captures the distance to the top of the cow’s back (hip height).

cattle ranchers measure hip height with laser sensors


Measuring Concrete Block Height


In-process quality assurance for uniform height of concrete pavers and wall blocks

Manufactured architectural concrete pavers and wall blocks are growing in demand because they last longer than site- poured concrete and because they offer fantastic choices of color, shape and texture. Furthermore, concrete pavers are relatively simple to install and do not require a mason’s training.

An OEM machine maker who has for years been making equipment for the concrete block industry, is addressing a quality asurance issue by integrating Acuity laser displacement sensors into a non-contact height measurement system. Using AR700 sensors (previously AR600 model), the system measures the height of molded concrete blocks as a conveyor passes them beneath a measurement archway.

The measurement environment is industrial in nature and the integrator took measures to block airborurne dust from collecting on the sensitive optics of the laser sensor. The product, called the “Blockqualifier”, is placed in service downstream from the block casting machine. Uncured bricks are placed on a steel palette which is conveyed beneath the archway of the Block Qualifier system. As it passes beneath, the AR700 sensors gage the height profile of the blocks. This information is displayed on an operator’s screen and processed in software algorithms to determine if they are within dimensional specification.



Postal Automation


The AR200 sensor is used for counting letter packs

Industrial automation is widespread in the letter and parcel handling centers around the world. Sensors are commonly used to detect and measure pieces of mail at blistering speeds. Integrators of Postal Automation systems use AR200 sensors for counting individual flat packs in long stacks.

Acuity’s novel sensor design is well suited to measuring to paper and cardstock materials of different colors. As the stacks of envelopes pass beneath the laser measuring sensor, the laser spot traverses the height profile. Software algorithms count each piece of mail.

The AR200 has a robust design can easily integrate into OEM systems because of its simple power and data interface requirements.

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