Panasonic SF2B Series Instruction Manual page 17

[For use in the United States of America (as per ANSI B11.19)]
● Equation 2
Ds
: Safety distance (mm)
Minimum required distance between the sensing area surface and the danger-
ous parts of the machine
K : Intrusion speed {Recommended value in OSHA is 63 (inch/sec.) [≈ 1,600 (mm/sec.)] }
ANSI B11.19 does not define the intrusion speed "K". When determining K, con-
sider possible factors including physical ability of operators.
Ts : Halting time calculated from the operation time of the control element (air valve, etc.) (sec.)
Tc : Maximum response time of the control circuit required for functioning the brake (sec.)
T : Response time of this device (sec.)
SF2B
T : Additional halting time tolerance for the brake monitor (sec.)
bm
The following equation holds when the machine is equipped with a brake monitor.
T
bm
T : Setting time of brake monitor (sec.)
a
When the machine is not equipped with a brake monitor, it is recommended that
20% or more of (Ts + Tc) is taken as additional halting time.
D
: Additional distance calculated from the size of the minimum sensing object of
pf
the device (mm)
SF2B-H□
SF2B-A□
Dpf = 3.4 × (d - 0.276) (inch)
≈ 3.4 × (d - 7) (mm)
d: Minimum sensing object diameter 1.063 (inch) ≈ 27 (mm) SF2B-H□
Minimum sensing object diameter 1.851 (inch) ≈ 47 (mm) SF2B-A□
<Reference>
Since the calculation above is performed by taking 1 (inch) = 25.4 (mm), there is a slight difference be-
tween the representation in (mm) and that in (inch). Refer to the relevant standard for the details.
<Calculation Example>
● Calculation Example 2 For use in the United States of America
[OFF response time: 15ms or less, minimum sensing object diameter: 1.063 (inch) ≈ 27 (mm)]
Ds = K × (Ts + Tc + T
= 63 × (Ta + 0.015) + 3.4 × (d - 0.276) (inch)
= 63 × (Ta + 0.015) + 3.4 × (1.063 - 0.276)
= 63 × Ta + 63 x 0.015 + 3.4 × 0.787
= 63 × Ta + 3.6208
≈ 63 × Ta + 3.62 (inch)
In case this device is installed in a system with a maximum halting time 0.1 (sec.)
Ds = 63 × Ta + 3.62
= 63 × 0.1 + 3.62
= 9.92 (inch)
≈ 251.968 (mm)
≈ 252 (mm)
Hence, as per the calculations
<Reference>
Since the calculation above is performed by taking 1 (inch) = 25.4 (mm), there is a slight difference be-
tween the representation in (mm) and that in (inch). Refer to the relevant standard for the details.
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Ds = K × (Ts + Tc + T
= Ta - (Ts + Tc)
Dpf = 2.676 (inch) ≈ 68 (mm)
Dpf = 5.355 (inch) ≈ 136 (mm)
+ T ) + D
SF2B bm
D s is 252 (mm).
+ T ) + D
SF2B bm
pf
pf
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