F3SJ-E/F3SJ-B/F3SJ-A
41
Possible Circumventing by Reaching Over the Detection Zone
If access to the hazardous zone by reaching over the detection
zone of vertically mounted F3SJ cannot be excluded, the height
and the safety distance, S, of the F3SJ shall be determined. S shall
be determined by comparison of the calculated values in
Detection
Zone Orthogonal to Direction of Approach
. The greater value
resulting from this comparison shall be applied.
S=(K × T) + Cro . . . Formula (5)
• S: Safety distance
• K: Approach speed to the detection zone
• T: Total response time of the machine and F3SJ
• Cro: Approach distance based on the distance which personnel
can move towards the hazardous zone of a machine by reaching
over the detection zone. The distance is determined in the table
below based on the height of the hazardous zone, a, and the
height of the upper edge of the detection zone, b.
Note:
Lower edge of the detection zone above 300 mm in relation to
the reference plane does not offer sufficient protection against
crawling below.
First, use K = 2,000 mm/s in formula (5) for the calculation. If the
result of this calculation is less than 100 mm, use S = 100 mm.
If the result exceeds 500 mm, use K = 1,600 mm/s to recalculate it.
If the result of the recalculation is less than 500 mm, use S = 500
mm.
Note: 1.
Upper edge of the detection zone below 900 mm is not included since they do not offer sufficient protection against circumventing or
stepping over.
2.
When determining the values of this table, it shall not be interpolated. If the known values a, b or Cro are between two values of this table,
the greater safety distance shall be used.
[Calculation example]
• T: Tm + Ts (s)
• Tm: Machine's response time (s)
• Ts: Response time of the F3SJ from ON to OFF (s)
• a: Height of machine hazardous zone (mm)
• b: Height of upper edge of detection zone (mm)
When Tm = 0.05 s, Ts = 0.01 s, a = 1,400 mm, b = 1,500 m:
From the table above, Cro = 850 mm. Since b is between 1,400
mm and 1,600 mm, b = 1,400 mm which has the greater Cro value,
shall be used.
S = 2,000 mm/s × (0.05 s + 0.01 s) + 850 mm
= 970 mm
Since 970 mm is greater than 500 mm, use K = 1,600 mm/s and
recalculate it.
S = 1,600 m/s × (0.05 s + 0.01 s) + 850 mm
= 946 mm
Compare S = 946 mm with the calculation in Detection Zone
Orthogonal to Direction of Approach, and choose the larger value
as the safety distance.
For the system with a detection capability of 40 mm max., the
safety distance S is 946 mm since this is larger than S = 120 mm
calculated in the calculation example of Detection Zone
Orthogonal to Direction of Approach.
For the system with a detection capability larger than 40 mm, the
safety distance S is 946 mm since this is the same value as S =
946 mm calculated in the calculation example of Detection Zone
Orthogonal to Direction of Approach.
Hazard
Safety
distance (S)
Reference plane
a
b
300 mm max.
Height of
hazardous
zone, a
Height of upper edge of detection zone, b
900
1000
1100
1200
1300
1400
1600
1800
2000
2200
2400
2600
Additional distance to hazardous zone, Cro
2600
0
0
0
0
0
0
0
0
0
0
0
0
2500
400
400
350
300
300
300
300
300
250
150
100
0
2400
550
550
550
500
450
450
400
400
300
250
100
0
2200
800
750
750
700
650
650
600
550
400
250
0
0
2000
950
950
850
850
800
750
700
550
400
0
0
0
1800
1100
1100
950
950
850
800
750
550
0
0
0
0
1600
1150
1150
1100
1000
900
850
750
450
0
0
0
0
1400
1200
1200
1100
1000
900
850
650
0
0
0
0
0
1200
1200
1200
1100
1000
850
800
0
0
0
0
0
0
1000
1200
1150
1050
950
750
700
0
0
0
0
0
0
800
1150
1050
950
800
500
450
0
0
0
0
0
0
600
1050
950
750
550
0
0
0
0
0
0
0
0
400
900
700
0
0
0
0
0
0
0
0
0
0
200
600
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0