Chapter
4
Operating Instructions
miniTwin2
24
© SICK AG • Industrial Safety Systems • Germany • All rights reserved
8013482/YT85/2016-02-23
Subject to change without notice
Mounting
Example:
Stopping/run-down time of the machine = 290 ms
Response time after light path interruption = 30 ms
Resolution of the safety light curtain = 14 mm
T = 290 ms + 30 ms = 320 ms = 0.32 s
S = 2000 × 0.32 + 8 × (14 – 14) = 640 mm
S > 500 mm, for this reason:
S = 1600 × 0.32 + 8 × (14 – 14) = 512 mm
How to calculate the minimum distance D
s
according to ANSI B11.19:2003
C
04,
Annex D and Code of Federal Regulations, Volume 29, Part 1910.217 … (h) (9) (v):
The following calculation shows an example calculation of the minimum 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
protective device
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 mm/second) is used for H
s
.
T
s
= Stopping/run down time of the machine tool measured after the final control
element
T
c
= Response time of the control system
T
r
= Response time of the entire protective device after light path interruption
T
bm
= Additional time to compensate for the lack of brake wear monitoring
Any additional response times must be accounted for in this calculation.
D
pf
= An additional distance added to the overall minimum 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:
For perpendicular protection using an opto-electronic protective device with an
object sensitivity (effective resolution) less than 2.5 inches (64 millimetres), D
pf
can be approximated based on the following formula:
D
pf
(inches) = 3.4 × (effective resolution – 0.276), but not less than 0.
Note
Note
