1107200
Shadow VI User Manual
page 24
Chapter 2
Installation and Checkout
Perimeter Guarding
DANGER
!
CONTROL INSIDE THE GUARDED AREA FOR PERIMETER GUARDING
Install the light curtain control outside the guarded area for perimeter guarding applications.
Failure to comply with these instructions will result in death or serious injury.
For perimeter safeguarding, there is another consideration: walking speed combined with the
hand speed. This is because personnel might be walking while simultaneously reaching into a
safeguarded area. Although there is no commonly accepted “walking speed constant” like the
“hand constant,” you might use ergonomic tables or possibly even 100 inches per second,
which is a conservative European “speed constant.” For perimeter guarding, the formula
would be:
D
s
= (100) x (T
s
+ T
c
+ T
r
+ T
bm
) + D
pf
Blanking Windows Affect Safety Distance
If you use a blanking window or floating blanking window, safety distance is affected,
because you are changing the sensitivity
of the light curtain. Remember, the minimum size
that Shadow VI can sense is an object 1.25" (3.17 cm) in diameter. Anything smaller might
fit between two light beams. This diameter (1.25") is called the
object sensitivity
of the light
curtain.
A blanking window or floating blanking window blocks one light beam, creating an
additional
3/4
" (1.9 cm) passageway through the light field where no object will be detected.
Now the object sensitivity equals 2" (5.08 cm) wide (1
1/4
"+
3/4
") and the
Dpf
= 5.9" (15 cm).
The ANSI safety distance formula states that if object sensitivity increases, the safety
distance must also increase. This means that use of blanking windows will require moving
the light curtain farther back from the hazardous area. The rule of thumb for increasing safety
distance is this:
Add 2.6" (6.6 cm) to the calculated safety distance for every blanking
window used up to 2 beams maximum.
However, if the area blanked is entirely blocked by a fixture such that operator intrusion into
this area is impossible, then you do not have to change the safety distance. For instance, you
might have a work table that juts out into the light field but takes up the whole space between
the transmitter and receiver which is unprotected by the light curtain.
You can blank more than one beam of the light curtain by adding slave windows to the
master blanking window. Always remove blanking windows when they are no longer
required.
Summary of Contents for Shadow VI
Page 142: ...1107200 Shadow VI User Manual page 130 Appendix C Installation of Shadow VI WPC Control Board ...
Page 144: ...1107200 Shadow VI User Manual page 132 Appendix D Replacement Parts ...
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