SICK WTT12-S Instrucciones De Funcionamiento página 22

OPERATING INSTRUCTIONS
4.7 Calculation of minimum distances in the application
en
4.8 Environmental influences
4.9 Manipulation
22 O P E R A T I N G I N S T R U C T I O N S | WTT12-S
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.
The minimum distance depends, among other things, on the following:
• Machine stopping time (time interval between triggering of the safety function and
assumption of the safe machine state, including signal propagation times in the
network and processing time in the controller)
• Response time of the entire protective device
•
Position of the device, e.g., on the vehicle
•
Speed of the sensor platform (e.g., consideration of dynamic measurement devia‐
tions)
• Approach speed of the objects
• Resolution (detection capability) of the device
• Type of approach
• Parameters specified based on the application
•
Supplements for general and, possibly, reflection-related measurement errors
The calculation of the minimum distances and the associated verification must be
performed by the system integrator on an application-specific basis.
The measurement by means of the time-of-flight method is well established and is
used in the single-echo method employed here only in the protected area (indoors)
in order to avoid inadvertent shadowing. This enables disturbances due to moisture,
condensation and contamination to be minimized.
Excessive light on the target or in the sensor may reduce the detection capability.
Avoiding reflectors and thereby reducing the presence of diffusely reflecting objects
increases the detection capability due to a lower dynamic range of the remission
factor. Measurement based on reflectors (as the target object) is not permitted in a
safety-related context.
Furthermore, the influence of dust in the application must be avoided. Dust particles
with a diameter > 1 mm (e.g., sawdust) in the beam path of the sensor can be
incorrectly identified as objects.
The device does not have any protective measures against manipulation, especially
none that relate to the optical system. Objects, especially objects covering the viewing
window and/or in the blind zone, are not detected by the device, causing impairment,
reduction or complete loss of detection capability, and the device no longer being able
to perform the safety function.
Manipulations with effects similar to undetected errors are also not detected.
8029123/2024/01/15 | SICK
Subject to change without notice