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F3SJ-A
User’s Manual
Chapter4 Installation Conditions
Wiring/Installation
E
How to calculate the safety distance specified by American standard ANSI B11.19
(reference)
If a person approaches the detection zone of the F3SJ perpendicularly, calculate the safety distance as
shown below.
S = K x (Ts + Tc + Tr + Tbm) + Dpf
•S: Safety distance
•K: Approach speed to the detection zone (the value recommended by OSHA standard is 1,600mm/s)
Approach speed K is not specified in the ANSI B.11.19 standard. To determine the value of K to apply,
consider all factors, including the operator's physical ability.
•Ts = Machine's stopping time (s)
•Tr = Response time of the F3SJ from ON to OFF (s)
•Tc = Machine control circuit's maximum response time required to activate its brake (s)
•Tbm = Additional time (s)
If a machine has a brake monitor, "Tbm= Brake monitor setting time - (Ts + Tc)". If it has no brake
monitor, we recommend using 20% or more of (Ts + Tc) as additional time.
•Dpf = Additional distance
According to ANSI's formula, Dpf is calculated as shown below:
Dpf = 3.4 x (d - 7.0): Where d is the detection capability of the F3SJ (unit: mm)
[Calculation example]
When K = 1,600mm/s, Ts + Tc = 0.06s, brake monitor setting time = 0.1s,
Tr = 0.01s, and d = 14mm:
Tbm = 0.1 - 0.06 = 0.04s
Dpf = 3.4 x (14 - 7.0) = 23.8mm
S = 1,600 x (0.06 + 0.01 + 0.04) + 23.8 = 199.8mm
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