Safety Integrated - Industry - Siemens

7
Cyclic
input data
0
OSSD
Warning!
Bits 0 to 6 must not be used for safety relevant
decisions. The fail-safe S7-CPU only has to evaluate
bit 7 in order to enable the successive actuator if
necessary.
Bits of the cyclic output data
Only individual bits, which are useful for understanding the
complete functionality, are discussed here. Proxy-Enable
(Bit 6):
Setting this bit is important for switching between the detection
zones (further information on detection zones available
at the bottom of this page).
Detection zone number (bits 0, 1, 2):
A detection / warning zone pair in LS4 is selected with this bit.
7
Cyclic
output data
0
Proxy-Enable
Detection zone number
Detection and warning zones
When using the LS4 you define detection and warning zones.
A detection zone (SF) and a warning zone (WF) always form a
zone pair. All in all, only 4 zone pairs can be defined, whereas
only one zone pair must be active at a time. Detection zone
numbers (bits 0, 1 and 2 of the cyclic output data) define the
zone pair (1, 2, 3 or 4) to be active. The Proxy-Enable bit of
the cyclic output data must be "0".
G_FB_XX_176
G_FB_XX_177
The detection and warning zones are defined with the LS4Soft
software. The PROFIsafe adapter enables correct time behavior
when switching the zone pairs.
A violation of detection and warning zones is indicated by
■ LEDs at the LS4 and by
■ the bits of the cyclic input data
Violation of warning zones are not evaluated in the STEP 7 example
program. A violation of the detection zone turns the
OSSD bit of the cyclic input data to "0", which changes the actuator
used in this example to the fail-safe status.
Example for an active zone pair
The robotic cell displayed below consists of two zone pairs:
Zone pair 1 (SF1, WF1): This zone is active, intrusion into SF1
stops the roboter.
Zone pair 2 (SF2, WF2): At the displayed point in time, the
specified detection and warning zone 2 may be entered.
NSC0_00646
WF 2
LS4
SF 2
SF 2
(active)
WF 1
(active)
Example project
The STEP 7 project used as an example in this document consists
of
■ a fail-safe S7-CPU (DP-Master),
■ the LS4 laser scanner for PROFIBUS (DP-Slave) as well as
■ standard and fail-safe input and output modules of ET 200S
(DP-Slave)
In this example, the actuator is simulated by an indicator light.
It is switched on and off via a fail-safe output (F-FO or the
ET 200S). If the detection zone of the LS4 is violated while the
output (indicator light ON) is switched (active), the indicator
light is automatically switched off. Restarting is only possible
in case of previous acknowledgement.
Functional Example No. AS-FE-I-010-V11-EN 293
Ex. No.
10