Page 32 - QR CIMAR LASER SCREED

LASER SYSTEM

The laser control system on the screed consists of (2) laser receivers referred to as SSR and an
operation control box called CBSSR. This laser control system is designed to operate at distances from
5 to 300 feet from the laser transmitter. If the distance between the laser transmitter and the SSR
receiver is less than 5 feet, the receiver may not register a laser strike. At distances greater than 300
feet, the system will still control elevation, but the level of accuracy may decrease.

The SSR receivers will work with most of the standard laser transmitters currently in use by the
construction industry. However, the transmitter you select will need to meet certain minimum guidelines
in order for the screed to perform at its best. The key things to look for are the rate at which the laser
transmitter rotates and the accuracy of the beam itself. (The rotation speed must be a minimum of
600rpm and the beam itself should be accurate to plus-or-minus 1/16 of an inch at 100 feet from the
transmitter.)

The laser receivers have a light that indicates when the unit has
power as well as visual grade indicators. The receivers are also
equipped with an array of optical individual segments arranged
along the vertical axis of the receivers. Whenever or below the
correct “stike-point”, the grade indicator on the receiver will
display an up-arrow or a down-arrow showing whether the
screed head is high or low relative to the reference signal. At
the same time, the receiver also sends a signal to the
Operations Box indicating whether the plow needs to move up
or down to remain on grade.

The Operations Box then activates the linear actuator on the
appropriate side of the plow until the reference beam is again
hitting the correct “strike-point” on the receiver.

Obviously, setting up these receivers correctly is crucial to the performance of the screed. In order to
set up the laser receivers on the screed to the correct height, a hand-held receiver is used in
conjunction with the Grade Rod to take benchmarks. A benchmark records the vertical distance
between the desired placement elevation and the laser signal emitted by the transmitter.
The hand-held receiver uses audio tones and a liquid crystal display arrow to tell the operator when it’s
directly in the path of the invisible laser beam. It operates in three modes, fine, medium and coarse. For
use with the screed it should always be in fine mode. We’ll discuss the details of how to take a
benchmark later in this manual.

Grade Rod

30