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© Panasonic Industrial Devices SUNX Co., Ltd. 2017
[For use in the United States of America (as per ANSI B11.19)]
●
Equation 2
Ds = K
×
(Ts + Tc + T
SF4B
+ T
bm
) + D
pf
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
SF4B
: Response time of this device (sec.)
T
bm
: Additional halting time tolerance for the brake monitor (sec.)
The following equation holds when the machine is equipped with a brake monitor.
T
bm
= Ta - (Ts + Tc)
T
a
: Setting time of brake monitor (sec.)
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
pf
: Additional distance calculated from the size of the minimum sensing object of
the device (mm)
SF4B-F□G<V2>
Dpf = 23.8mm
SF4B-H□G<V2>
Dpf = 61.2mm
SF4B-A□G<V2>
Dpf = 129.2mm
Dpf = 3.4 × (d - 0.276) (inch)
≈ 3.4 × (d - 7) (mm)
d: Minimum sensing object diameter 0.552 (inch) ≈ 14 (mm)
SF4B-F□G<V2>
Minimum sensing object diameter 0.985 (inch) ≈ 25 (mm)
SF4B-H□G<V2>
Minimum sensing object diameter 1.772 (inch) ≈ 45 (mm)
SF4B-A□G<V2>
When the floating blanking function is applied, the minimum sensing object becomes large. According to
ANSI B11.1, Dpf = 900mm (3ft) when d > 64mm (2.5 inches).
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: 14ms or less, minimum sensing object diameter: 0.552 (inch) ≈ 14 (mm)]
Ds
= K × (Ts + Tc + T
SF4B
+
T
bm
) + D
pf
= 63 × (Ta + 0.014) + 3.4 × (d - 0.276) (inch)
= 63 × (Ta + 0.014) + 3.4 × (0.552 - 0.276)
= 63 × Ta + 63 x 0.014 + 3.4 × 0.276
= 63 × Ta + 1.8204
≈ 63 × Ta + 1.82 (inch)
In case this device is installed in a system with a maximum halting time 0.1 (sec.)
Ds
= 63 × Ta + 1.82
= 63 × 0.1 + 1.82
= 8.12 (inch)
≈ 206.248 (mm)
Hence, as per the calculations
D
s is 206.2 (mm).
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.
<Reference>
<Reference>
<Reference>