Rockwell Automation 442L SC300 Safety Sensor User Manual - Manual (Page 20)

18 Rockwell Automation Publication 10000202762 Ver 00 - January 2012
Chapter 4 Mounting
K = 2000 mm/s
Definition and value as per prEN ISO 13 855, derived from data on the approach
speed of the body or parts of the body
T = Stopping/run-down time of the entire system in [s]
Stopping/run-down time of the entire system = Stopping/run-down time of the
machine + response time of the protective device after light path interruption
d = Detection capability (resolution) of the protective device in [mm]
The reach/approach speed is already included in the calculation formula.
With K = 2000 mm/s the 1st formula is:
1. calculation formula: S = 2000 × T + 8 × (d – 14)
If the result S is
≥ 100 mm and S ≤ 500 mm, then use the determined value as the safety
distance.
Note As per prEN ISO 13 855 a safety distance S < 100 mm is not allowed. If you obtain a
value S < 100 mm with your calculation, please contact Rockwell Automation.
If the result is S > 500 mm, use K = 1600 mm/s in the formula and calculate S again:
2. calculation formula: S = 1600 × T + 8 × (d – 14)
If the new value S is > 500 mm, then use the newly determined value as the minimum
safety distance.
If the new value S is
≤ 500 mm, then use 500 mm as the minimum safety distance.
Example:
The following values apply:
Stopping/run-down time of the machine = 290 ms
Response time of the SC300 after light path interruption = 20 ms
Detection capability (resolution) d of the SC300 = 20 mm
Note You will find the values for the response time and the resolution of the SC300 in
“Technical specifications” on page 47.
Minimum safety distance calculation:
• Step 1: Calculation of the stopping/run-down time of the entire system:
T = 290 ms + 20 ms = 310 ms = 0.31 s
• Step 2: Insert the values in the 1st formula (S = 2000 × T + 8 × (d – 14)):
S = 2000 Ч 0.31 + 8 Ч (20 – 14) = 668 mm
• Step 3: Check the value for S.
S > 500 mm. For this reason the 2nd formula must be used.
• Step 4: Insert the values in the 2nd formula (S = 1600 × T + 8 × (d – 14)):
S = 600 Ч 0.31 + 8 Ч (20 – 14) = 544 mm
• Step 5: Check the value of S.
S > 500 mm. For this reason 544 mm must be used as the minimum safety distance.