LINK Systems Max Presence Sensing Device - Manual (Page 7)

Link Lite Black Max Section 3 - Installation
3-2
selected by the user/employer to install the
barriers must:
1. Determine where barriers are
necessary and the location and size of
barriers.
2. Design and fabricate (or have fabri-
cated) the necessary barriers.
3. Mount the barriers and confirm their
effectiveness and that pinch points or other
hazards are not created between barriers and
moving machine parts.
Supplemental guard requirements are
discussed in more detail in section 3.9.
3.3 Calculating the Required Black
Max Safety Distance.
Every machine requires a period of time
(stopping time) to stop hazardous action
after a stop signal is applied to its control
system because of reaction times in control
components, valves, and actuators and
because of inertial effects of moving
machine parts. All light curtains also have a
reaction time to detect an object in their
sensing field and send a stop signal. The
Link Lite Black Max must be installed to
provide an OSHA and ANSI required
minimum safety distance, D
s
, between its
primary sensing field and the nearest point
of operation hazard, or other moving
machine hazard to be safeguarded. This
safety distance must be calculated by a
formula specified by OSHA and ANSI
standards. The safety distance is intended
to prevent injury by requiring a longer time
for a person to reach the hazardous area
after interrupting the presence sensing field
than the time it takes to stop the machine
action that poses the hazard. Figure 3.1
depicts one application of the safety
distance.
Figure 3.1: Minimum Safety Distance
The Minimum safety distance in the most
recent ANSI standards is calculated by the
formula:
D
S
= K (T
s
+T
c
+T
r
+T
bm
) + D
pf
Where:
D
s
= the required minimum safety dis-
tance
K = 63 in/sec (the average handspeed
constant)
WARNING!! The Link Lite Black
Max must be installed at a distance
greater than or equal to the safety
distance, D
s
.Failure to do so can
result in serious injury to personnel
because it may be possible to reach
into the hazardous area before the
machine can stop.