38
EN
5.4.4.3 Calculating Safety Clearance
Light curtain resolution is identical to electronically reduced resolution in the “reduced resolution” operating mode
(see table).
Table: Reduced Resolution
• Finger protection:
max. reduced resolution = 105 mm
• Hand protection:
max. reduced resolution = 98 mm
Number of
muted beams
Resolution
d for
SG4-14 (Finger
protection)
7 mm steps
Resolution
d for
SG4-30 (Hand
protection)
17 mm steps
1
21 mm
47 mm
2
28 mm
64 mm
3
35 mm
81 mm
4
42 mm
98 mm
5
49 mm
6
56 mm
7
63 mm
8
70 mm
9
77 mm
10
84 mm
11
91 mm
12
98 mm
13
105 mm
Recalculation of safety clearance SG4-14Ix075C1: S = (K × T) + 8 × (d – 14 mm)
Assuming:
Light Curtain response time
t
1
= 26 ms
Machine over-travel time
t
2
= 20 ms
S = (K × T) + 8 × (d – 14 mm)
Example 1: light curtain resolution: d = 14 mm (electronically reduced to 35 mm), vertical installation:
S = 2000 mm/s × 0,046 s + 8 (35 mm – 14 mm) = 260 mm
(without reduced resolution: S = 100 mm minimum clearance)
Example 2: light curtain resolution: d = 14 mm (electronically reduced to 42 mm), vertical installation:
Because resolution is greater than 40 mm, C = 850 mm (see section 3.3, „Calculating Safety Clearance per EN ISO
13855“).
Due to the fact that a safety clearance of 500 mm results alone from C, we only need to use K = 1600 mm/s for our cal-
culation.
S = 1600 mm/s × 0,046 + 850 = 923,6 mm
These examples demonstrate that a larger safety clearance results from a lower resolution.
A side-stepping safety device may be required in this case!
