LINK Systems Max Presence Sensing Device - Manual (Page 35)

Link Lite Black Max Section 4 - Operating Instructions
4-2
2. The main Black Max sensing field must
be located far enough away from the
hazardous area that machine action will be
stopped before a persons hand that passes
through the light curtain sensing field can
reach the closest hazard. This safety
distance is required by both OSHA and
ANSI. The minimum safety distance, D
S
, is
determined by a formula which is ex-
plained in section 3.3 of the installation
section of this manual.
It must never be assumed that the original
installation of a Black Max light curtain will
always result in maintaining D
S
for all
setups and under all operating conditions.
For several reasons, safety distance must be
verified for each setup under actual
operating conditions.
First, D
S
depends on the stopping time, T
S
,
of the machine, which can vary depending
on many factors, including position in
stroke, cycle rate, air or hydraulic pressure,
speed of moving parts (stroking speed),
temperature of hydraulic fluid, weight of
tooling attached to moving machine parts,
and counterbalance adjustment. On
machines equipped with friction clutches
and brakes, clutch and brake wear over a
period of time can cause the stopping time
to increase. Some hydraulically operated
machines have adjustments that can affect
stopping time.
Second, the size and location of the tooling
used in a machine often varies for each
machine setup, bringing the hazardous
point of operation closer or farther away
from the Black Max sensing field on
different setups and thus affecting D
S
. For
this reason the person(s) assigned to set the
machine up for different production jobs
must verify the safety distance for each
setup. See Figure 4.2
Figure 4.2: Illustration of Minimum Safety
Distance Measurement
3. Light curtains, including the Black
Max, only protect people who reach
through their sensing field as they ap-
proach the hazard to be safeguarded.
Depending on the safety system design and
the machine or production system config-
uration, supplemental barriers may be
WARNING! The Link Lite Black Max
sensing field must be located 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 is possible to reach into the
hazardous area before the machine can
stop.
WARNING! The Black Max light
curtain will not protect you if you
reach over, under, or around its sensing
field and into the hazard. Serious
injury may result if you can enter the
hazard other than through the Black
Max sensing field.