Rockwell Automation 445L GuardShield Safe 4 and Safe 4 PAC Safety Light Curtains User Manual - Manual (Page 10)

R
GuardShield™ Safe 4 Safety Light Curtain User Manual
8
Original instructions
d = resolution of the light curtain [mm]
S = safety distance [mm]
The reach/approach speed is already included in the
formula.
-> If the result S is  500 mm (19.6 in.), then use the determined
value as the safety distance.
-> If the result S is > 500 mm (19.6 in.), then recalculate S as
follows: S = 1600 × T + 8 × (d – 14) [mm]
-> If the new value S is > 500 mm (19.6 in.), then use the newly
determined value as the minimum safety distance.
-> If the new value S is  500 mm (19.6 in.), then use 500 mm
(19.6 in.) as the safety distance.
Example:
Stopping/run-down time of the machine = 290 ms
Response time = 30 ms
Resolution of the light curtain = 14 mm (0.55 in.)
T = 290 ms + 30 ms = 320 ms = 0.32 s
S = 2000 Ч 0.32 + 8 Ч (14 – 14) = 640 mm (25.1 in.)
S > 500 mm, therefore:
S = 1600 Ч 0.32 + 8 Ч (14 – 14) = 512 mm (20.1 in.)
How to Calculate the Safety Distance S for
GuardShield Safe 4 PAC Systems
In the case of perimeter systems or light curtains with a resolution
d > 40 mm, the safety distance is calculated for vertical mounting
light curtains and horizontal approach, according to the formula:
S = 1.6 mm/ms x T + 850 mm
More detailed information regarding safety distance and safety
heights can be found in standard EN 13855 (2010).
Minimum Distance from Reflecting Surfaces
The infrared light from the sender may be reflected off of shiny
surfaces and be received by the system’s receiver. If this condition
occurs, it can result in an object not being detected when it enters
the GuardShield Safe 4 sensing field.
All reflecting surfaces and objects (e.g. material bins) must
therefore be located at a minimum distance a from the protective
field of the system. The minimum distance a depends on the
distance D between sender and receiver.
Figure 4: Minimum distance from reflecting surfaces
How to Determine the Minimum Distance from the Reflecting Surfaces:
• Determine the distance D [m] sender-receiver
• Read the minimum distance a [mm] from the graph:
Figure 5: Graph, minimum distance from reflecting surfaces
The effective aperture angle for the GuardShield Safe 4 system is
±2.5° at a mounting distance of > 3.0 m (9.8 ft). Calculate the
minimum distance to reflecting surfaces depending on the
distance between the transmitter and the receiver, using an
aperture angle of ±2.5°, or take the appropriate value from the
following table:
Formula: a = tan 2.5° x D [mm]
a = minimum distance to reflecting surfaces
D = distance between transmitter and receiver
Installation and Mounting
This section describes the preparation, selection and installation
of the GuardShield Safe 4 safety light curtain. Mount and connect
both transmitter and receiver.
Determine if the machinery, on which the GuardShield Safe 4 is to
be mounted, meets the requirements as specified in the
beginning of this manual, i.e., machinery must be able to be
Distance D (meters)
Distance Between
Transmitter and Receiver
(Range D) [m (ft)]
Minimum Distance
a [mm (in.)]
0…3.0 (0…9.8) 135 (5.31)
4.0 (13.1) 175 (6.88)
5.0 (16.4) 220 (8.66)
6.0 (19.6) 265 (10.43)
7.0 (22.9) 310 (12.2)
10.0 (32.8) 440 (17.32)
16.0 (52.4) 700 (27.55)
IMPORTANT
The installation of the GuardShield Safe 4
safety light curtain must be such that access
to the hazard is only possible through the
sensing field of the GuardShield Safe 4.
Auxiliary safe guarding may be required in
conjunction with the GuardShield Safe 4 to
meet this requirement.