Reduced Resolution
Depth Penetration Factor (Dpf)
14 mm Systems
25 mm Systems
ON
92 mm (3.6 in)
915 mm (36 in)
Notes:
1. The OSHA-recommended hand speed constant K has been determined by various studies and, although
these studies indicate speeds of 1600 mm/sec. (63 in/sec.) to more than 2500 mm/sec. (100 in/sec.), they
are not conclusive determinations. Consider all factors, including the physical ability of the operator, when
determining the value of K to be used.
2. The recommended hand speed constant K, derived from data on approach speeds of the body or parts of
the body as stated in ISO 13855.
3. Ts is usually measured by a stop-time measuring device. If the machine manufacturer's specified stop time
is used, at least 20% should be added to allow for possible clutch/ brake system deterioration. This
measurement must take into account the slower of the two MPCE channels, and the response time of all
devices or controls that react to stop the machine.
WARNING:
• Stop time (Ts) must include the response time of all devices or controls that react to stop the
machine
• If all devices are not included, the calculated safety distance (Ds or S) will be too short, which can
lead to serious injury or death.
• Include the stop time of all relevant devices and controls in your calculations.
• If required, each of the two machine primary control elements (MPCE1 and MPCE2) must be
capable of immediately stopping the dangerous machine motion, regardless of the state of the
other. These two channels of machine control need not be identical, but the stop time
performance of the machine (Ts, used to calculate the safety distance) must take into account the
slower of the two channels.
5.1.3 Examples
Example: U.S. Applications, Model SLPM..14-550
K
= 63 in. per second (the hand speed constant set by OSHA)
Ts
= 0.32 (0.250 second is specified by the machine
manufacturer; plus 20% safety factor; plus 20 ms for
interface module IM-T-9A response time)
Tr
= 0.0165 seconds (the specified response time of an SLPM..
14-550 EZ-SCREEN LPM)
Dpf
= 3.6 in (14 mm resolution, Reduced Resolution ON)
Substitute the numbers into the formula as follows:
Ds = K × ( Ts + Tr ) + Dpf
Ds = 63 × (0.32 + 0.0165) + 3.6 = 24.8 in
Mount the EZ-SCREEN LPM emitter and receiver so that no part of the
defined area will be closer than 24.8 in. to the closest reachable hazard
point on the guarded machine.
Example: European Applications, Model SLPM..14-550
K
= 1600 mm per second
T
= 0.32 (0.250 second specified by machine manufacturer;
plus 20% safety factor; plus 20 ms interface module
response time), plus 0.0165 seconds (the specified
SLPM..14-550 response time)
C
= 8 x (34 - 14) = 160 mm (14 mm resolution, Reduced
Resolution ON)
Substitute the numbers into the formula as follows:
S = (K × T ) + C
S = (1600 x 0.336) + 128 = 665.6 mmS = (1600 ×
0.3365) + 160 = 698.4 mm
Mount the EZ-SCREEN LPM emitter and receiver so that no part of
the defined area will be closer than 698.4 mm to the closest
reachable hazard point on the guarded machine.
5.1.4 Reducing or Eliminating Pass-Through Hazards
A
pass-through
hazard is associated with applications where personnel may pass through a safeguard, such as the EZ-
SCREEN Low-Profile System with Integral Muting (which issues a stop command to remove the hazard), and then continues
into the guarded area. This is common in access and perimeter guarding applications. Subsequently, their presence is no
longer detected, and the related danger becomes the unexpected start or restart of the machine while personnel are within
the guarded area.
EZ-SCREEN Low-Profile System with Integral Muting
www.bannerengineering.com - Tel: + 1 888 373 6767
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