LaserGuard2 Instruction Manual
April 2015
Page 8 of 31
A rugged, fully adjustable mount is also supplied with the system, along with a reflective target. The target
is mounted on the wall or other crane that is going to be protected by the collision avoidance system.
The LSU contains three fully adjustable range detectors and a fault detector. The range detectors are
adjustable to trip the relays from approximately 8 in. to 150 ft., where the warning detector is set for the
distance that the warning should appear at, or where the first stage of crane deceleration takes place.
Slowdown sets stage two of deceleration, and the third detector is used to set the point where the crane
brakes should be applied. The relationship between these points is as follows:
150 ft.
≥
Warning > Slowdown > Stop
≥
8 in.
If the above sequence is not maintained, an out-of-sequence error will occur, which will drop out all range
points and the fault detector. This will stop the crane and prevent it from being moved in the protected
direction until the sequence is corrected. The FAULT LED (DS5) will flash three times, pause, and repeat
until the sequence is in the correct order.
2.4.
Optical Path Fault Detector
When the system detects a loss in the optical path due to obstructions or misalignment of the laser and its
target, it will produce a 10 second fault. This will cause the fault relay and the range point relays to drop
out for 10 seconds. After this 10-second period, the system will return back to normal operation until the
fault is detected again. If the laser beam is continuously lost or blocked, the controls will act as if the
laser is out of range and allow the operator to run at full speed after the 10-second period. This is the only
fault condition that lasts 10 seconds (all other fault conditions do not time out), thereby making it easy to
determine that an optical path problem has occurred and maintenance is needed to tighten or realign the
laser mounting and/or the reflector.
2.5. Fault
Relay
A separate form C relay is provided to drive a warning light or enunciator in the event of a fault. The relay
is normally energized and if a fault occurs the relay switches. Faults include the loss of the target, setting
out of sequence, undercurrent, or overcurrent.
