5
EN
SLC 420 IP 69 K
Operating instructions
Safety light curtain
2.8.3 Fixed blanking
The SLC 420 can blank stationary parts in the protection field
Multiple protection field areas can be blanked If small changes are
made within the fixed blanking area, each time 1 beam can be addition-
nally blanked to increase the tolerance Refer to the chapter Variable
blanking
Fixed blanking area
E1
R1
The range of the fixed blanking can be arbitrarily chosen in the protec-
tion field
The first beam line, which realises the optical synchronisation and is
located immediately behind the diagnostic window, cannot be blanked
The area of the fixed blanking must not be modified after the teach-in
process Any change of the area or removal of the part from the protec-
tion field will be detected by the system As a result, the outputs are
disabled (locked) This locking can be neutralised by executing a new
teach-in process in accordance with the actual beam interruptions
The function is activated by means of the NSR-0801 BUS
converter and a PC or laptop The activation of the function
is signaled by the LED blanking flashing in the diagnostic
window of the receiver
The remaining lateral areas must be protected against intru-
sion by means of mechanical covers
The lateral covers must be fixed with the object
Partial covers are not authorised
After the fixed blanking, the protection field must be tested by
means of the test rod
The restart interlock function of the safety light curtain or the
machine must be activated
The standard IEC/TS 62046 includes information, which
describes possibly required additional measures to prevent a
person from reaching a hazard through the blanking areas of
a protection field
2.8.4 Variable blanking
The SLC 420 can blank movable parts in the protection field
Cylinder for material ejection
The function enables an arbitrary floating blanking of partial areas in the
protection field The first beam, which is located immediately behind the
diagnostic window, cannot be blanked
The SLC 420 can blank one or more beams in the protection field A
combination of fixed and variable blanking is possible
This function allows for an interruption of the protection height without
the outputs being disabled in case of material movement in the protec-
tion field, eg material ejection or process-controlled material move-
ment This extension of the object detection increases the resolution
In this way, the physical resolution changes into an effective resolution
This effective resolution must be used to calculate the safety distance
This effective resolution must be used to calculate the safety distance
Use formula (2) to calculate the safety distance with the effective
resolution if a maximum of 1 light beams are blanked; use formula (2)
indicated in the "Safety distance" chapter if more than 3 light beams are
blanked
The number of beams to be blanked is limited by the software
In a system with a 14 mm physical resolution, the effective resolution
is increased to 34 mm in case of a variable blanking of 2 beams The
effective resolution must be registered permanently and clearly visible
onto the label affixed to the receiver
Effective resolution
The effective resolution in case of activated blanking of floating beams
can be found in the following table:
Beams
blanked
Physical
Resolution
Effective
resolution
1
14
24
2
14
34
3
14
44
4
14
54
5
14
64
6
14
74
7
14
84
8
14
94
Beams
blanked
Physical resolution Effective resolution
1
30
45
2
30
65
3
30
85
4
30
105
The function is activated by means of the NSR-0801 BUS
converter and a PC or laptop The activation of the function
is signaled by the LED blanking flashing in the diagnostic
window of the receiver
Perform a new calculation of the safety distance with the
effective resolution Adjust the safety distance in accordance
with your calculation!
After configuration, the protection field must be checked by a
responsible person by means of a test rod; in addition to that,
this person must compare the size of the blanked area to the
object size and if necessary provide for additional covers or a
larger distance of the safety guard with regard to the hazard-
ous point The standard IEC/TS 62046 includes information,
which describes possibly required additional measures to
prevent a person from reaching a hazard through the blank-
ing areas of a protection field
