Rockwell Automation 442L SafeZone Singlezone & Multizone Safety Laser Scanner - Manual (Page 9)

R
SafeZone™ Safety Laser Scanner User Manual
10000073050, July 2011 7
Original instructions
• It must be possible to transfer the dangerous state of the machine, the
equipment or the vehicle to a safe state at any time using the OSSDs
on the SafeZone safety laser scanner after integration in the
controller.
• The SafeZone safety laser scanner must be mounted and configured
such that it detects objects as they enter the hazardous area (see
Section 4 “Installation and mounting” on page 18).
3.2.1 Principles of operation
The SafeZone safety laser scanner is an optical sensor that scans its
surroundings in two dimensions using infrared laser beams. It is used to
monitor a hazardous area on a machine or a vehicle.
Figure 1: Principle of operation, time of flight measurement by the
SafeZone safety laser scanner
The SafeZone safety laser scanner works on the principle of time of flight
measurement
Œ. It sends out very short pulses of infrared light (S). At
the same time an “electronic stopwatch” is started. When the light is
reflected off of an object, it is received by the safety laser scanner (E).
From the time between sending and receiving (
Δ
t) the SafeZone
multizone safety laser scanner calculates the distance to the object.
In the SafeZone safety laser scanner there is also a mirror rotating at
constant speed
 that deflects the light pulses such that they cover an arc
of 190°. By determining the angle of rotation of the mirror, the SafeZone
safety laser scanner determines the direction of the object.
From the measured distance and the direction of the object, the safety
laser scanner determines the exact position of the object.
Figure 2: Principle of operation of the SafeZone safety laser
scanner—light pulses
The SafeZone safety laser scanner uses light pulses precisely radiated in
specific directions. Thus the laser scanner does not continuously cover
the area to be monitored. In this way resolutions of between 30 mm and
150 mm are achieved.
Due to its active scanning principle, the SafeZone safety laser scanner
does not require receivers or reflectors. This has the following
advantages:
• Ease of installation.
• You can easily adapt the monitored area to the hazardous area on a
machine.
• In comparison with contact sensors, there is less wear when electro-
sensitive scanning is used.
3.2.2 Field set comprised of protective safety field and
warning field
Figure 3: Protective safety field and warning field
The protective safety field Πsecures the hazardous area on a machine or
vehicle. As soon as the safety laser scanner detects an object in the
protective safety field, it switches the OSSDs to the off status and thus
initiates the shutdown of the machine or stop of the vehicle.
You can define the warning field  such that the safety laser scanner detects
an object before the actual hazardous area and e.g. triggers a warning signal.
The protective safety field and warning field form a pair, the so-called
field set. With the aid of the SCD you can configure these field sets and
transfer them to the SafeZone safety laser scanner. If the area to be
monitored changes, then you can re-configure the SafeZone safety laser
scanner in software without additional mounting effort.
The SafeZone Singlezone has a single configurable field set. The
SafeZone Multizone has up to four configurable field sets. The SafeZone
Multizone allows switching between field sets if the monitoring situation
changes (see Section 3.2.3 “Monitoring cases” below).
3.2.3 Monitoring cases
Four monitoring cases can be defined in the SafeZone multizone and
selected during operation using static control input. Each monitoring
case includes:
• The input conditions, the so-called control signals, that control the
activation of the monitoring case.
• A field set, comprising protective safety field and warning field.
• If necessary, a simultaneous field set without separate outputs.
Δ t
S R
S – Δ t
S
R

Œ