4.3.7.3
Minimum distance for stationary applications
Overview
You must ensure the minimum distance between the protective field and hazardous
point is adhered to. The minimum distance means that the dangerous state can be
ended in good time before the person reaches the hazardous point.
Minimum distance for stationary applications
The calculation of the minimum distance is based on international or national stand‐
ards and statutory requirements applicable at the place of installation of the machine.
If the minimum distance is calculated according to ISO 13855, then it depends on the
following points:
•
Machine stopping time (time interval between triggering the sensor function and
the end of the machine’s dangerous state, if necessary including signal propaga‐
tion times in the network and processing time in the control)
•
Response time of the protective device
•
Reach or approach speed of the person
•
Resolution (detection capability) of the safe multibeam scanner
•
Type of approach: orthogonal for access protection
•
Switching time between monitoring cases
•
Supplement to prevent reaching through
Complementary information
Additional information is available in the ISO 13855 standard and in the Guide for Safe
Machinery from SICK.
SICK offers a stopping/run-down time measurement service in many countries.
Further topics
•
"Response time of the safe multibeam scanner", page 20
•
"Monitoring case switching", page 20
4.3.7.4
Calculation example for the minimum distance
Calculation example of the minimum distance S according to ISO 13855
The example shows the calculation of the minimum distance for an orthogonal
approach to the protective field. A different calculation may be required, depending
on the application and the ambient conditions (e.g. for a protective field parallel to or at
any angle to the direction of approach or an indirect approach).
S = 1,600 mm/s × T +850 mm
where:
•
S = minimum distance in millimeters (mm)
•
T = stopping/run-down time for the entire system in seconds (s)
(Response time of the safe multibeam s machine’s stopping/run-down
time, incl. response time of the machine’s control system and signal propagation
time)
The approach speed is already included in the formula.
PROJECT PLANNING
4
8025990/2021-03-03 | SICK
O P E R A T I N G I N S T R U C T I O N S | scanGrid2 CANopen
29
Subject to change without notice
