Safety Integrated - Industry - Siemens

Light Curtain in Category 4 with Muting Function
acc. to EN 954-1
Automation Function
Description of the functionality
Light curtain
SIGUARD light curtains 3RG7844 meet the requirements of
Safety Category 4 according to IEC 61496-1 : 2004 and
EN 61496-1 : 2004 The relevant machine safety regulations apply
for the application, particularly:
■ machinery directive 98/37/EC and
■ work equipment directive 89/655/EEC
The SIGUARD light curtain used here is mainly used in vertical
arrangement of the danger spot protection (see figure). With
the physical resolution of 30 millimeters, hand/arm are safely
detected in a range from 0.8 to 18 meters.
SIGUARD light curtains 3RG7844 consist of a transmitter and
a receiver (see figure).
Sender Receiver
Starting with the first beam (= synchronization beam), the
transmitter quickly pulses beam after beam. The receiver detects
the specially formed pulse packets of the send beams
and successively opens the linked receive elements with the
same rhythm. This ensures that a protection field is created
between transmitter and receiver. Transmitter and receiver
are synchronized optically.
G_FB_XX_117
Light curtains can only realize their protective effect, if they
are installed with an adequate safety margin. The formulas
used to calculate the safety margin depend on the type of protection.
Mounting situations and calculation formulas are
available in the standard EN 999 ("The positioning of protective
equipment in respect of approach speeds of parts of the
human body"). The formula for the required distance to reflecting
areas complies with the European Standard for "Active
Opto-Electronic Protective Devices" prEN IEC 61496-2 : 1997.
The transmitter and receiver type used in this example provides
a 12-pin Hirschmann connector (see figure).
The Hirschmann connector uses the following pins:
Transmitter
Pin Input / output Connected to Note
1 Input +24 V DC Supply
2 Input 0 V DC
3 Output Pin 4 No internal jumper set in
4 Input Pin 3
factory
Receiver
Pin Input / output Connected to Note
1 Input +24 V DC Supply
2 Input 0 V DC
3 Output F-DI OSSD1
4 Output F-DI OSSD2
OSSD1 and OSSD2 are the safety-relevant switching outputs
(Output Signal Switching Devices). They are placed on the F-
DI and polled by the F CPU using a 1oo2 evaluation. "0" signal
means: Light curtain is interrupted. The F program causes the
stop of the hazardous machine.
Warning!
In this example, the hazardous machine is simulated
by an indicator light. When using other actuators than
this indicator light, safe switching-off of the loads including
signal feedback is to be supplemented.
Functional Example No. AS-FE-I-005-V10-EN 219
Ex. No.
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