Operating Instructions Chapter 5
C 4000 Standard/Advanced
8 009 861/OE59/19-11-04 © SICK AG • Industrial Safety Systems • Germany • All rights reserved
39
Installation and mounting
How to calculate the safety distance D
s
according to ANSI B11.19-1990 E.4.2.3.3.5 and
Code of Federal Regulations, Volume 29, Part 1910.217 … (h) (9) (v):
The following calculation shows an example calculation of the safety distance. Depending
on the application and the ambient conditions, a different calculation may be necessary.
Calculate D
s
using the following formula:
D
s
=H
s
× (T
s
+ T
c
+ T
r
+ T
bm
) + D
pf
Where …
D
s
= The minimum distance in inches (or millimetres) from the hazardous point to the
detection point, plan or zone
H
s
= A parameter in inches/second or millimetres/second, derived from data on
approach speeds of the body or parts of the body. Often 63 inches/second
(1600 millimetres/second) is used for H
s
.
T
s
= Stopping time of the machine tool measured at the final control element
T
c
= Response time of the control system
T
r
= Response time of the presence-sensing device and its interface
T
bm
= Additional response time allowed for brake monitor to compensate for wear
Any additional time delays must be accounted for in this calculation.
D
pf
= An additional distance added to the overall safety distance required. This value is
based on intrusion toward the hazardous point prior to actuation of the electro-
sensitive protective equipment (ESPE). Values range from 0.25 inches to
48 inches (6 to 1220 millimetres) or more depending on application.
Example:
In opto-electronic protection, such as with a perpendicular safety light curtain
applications with object sensitivity (effective resolution) less than 2.5 inches
(64 millimetres), the D
pf
can be approximated based on the following formula:
D
pf
(inches) = 3.4 × (object sensitivity – 0.276), but not less than 0.
Note
Note
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