Banner EZ-SCREEN­ Safety Light Curtain Systems - Manual (Page 16)

Examples
Example: U.S. Applications, Model LS2..30-600
K = 63" 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)
Tr = 0.016 second (the specified response time of an
LS2..30-600 EZ-SCREEN Type 2)
Dpf = 3"
Substitute the numbers into the formula as follows:
Ds = K x ( Ts + Tr ) + Dpf
Ds = 63 x (0.32 + 0.016) + 3 = 24.2"
Mount the EZ-SCREEN Type 2 emitter and receiver so that no
part of the defined area will be closer than 24.2" to the closest
reachable hazard point on the guarded machine.
Example: European Applications, Model LS2..30-600
K = 1600 mm per second
T = 0.336 (0.250 second specified by machine manufac-
turer; plus 20% safety factor; plus 20 ms interface
module response), plus 0.016 second (the specified
LS2..30-600 response time)
C = 8 x (30-14) = 128 mm
Substitute the numbers into the formula as follows:
S = (K x T ) + C
S = (1600 x 0.336) + 128 = 665.6 mm
Mount the EZ-SCREEN Type 2 emitter and receiver so that no
part of the defined area will be closer than 665.6 mm to the clos-
est reachable hazard point on the guarded machine.
WARNING: Determine Correct Stop Time
Stop time (Ts) must include the response time of all devices or controls that react to stop the ma-
chine. If all devices are not included, the calculated safety distance (Ds) will be too short. This can lead to
an increased risk of harm. Be sure to 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 chan-
nels 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.
EZ-SCREEN® Type 2 Light Screen Instruction Manual
16 www.bannerengineering.com - tel: 763-544-3164 122452 rev. B