Safety Integrated - Industry - Siemens

Ex. No.
5
Program procedure
OB 1 defines the start conditions for the hazardous machine
(here simulated by an indicator light):
"START"
"P"
P &
"MS_11"
"MS_12"
"MS_21"
"MS_22"
"INSTANZ_
FB1".FAULT
STOP"
>=1
"SR"
SR
S
R Q
"COND"
=
G_FB_XX_128
Parameter Adress Explanation
START E 0.0 (NO) Start request
MS_11 E 1.0 Optical proximity switch (as muting
MS_12
MS_21
E 1.1
E 2.0
sensor) Any type of sensor can be
used which need not be failsafe.
Convention: At the "1" signal the ob-
MS_22 E 2.1 ject is recognized.
INSTANZ_FB1. DB1.DBX4.2 This bit causes a start of the "ma-
FAULT
chine" to only be possible after previous
acknowledgement. The signal
status of this bit is defined in the
safety program (FB 1) and filed in its
respective instance DB (DB1, byte 4,
bit 2)
STOP M 92.3 Dummy bit In this example, no operational
stopping has been implemented.
If you wish to extend the
example accordingly, the memory bit
can be replaced by the respective
sensor signal.
COND M 92.0 Sets or resets the machine (in FB 1 of
the safety program).
230 Functional Example No. AS-FE-I-005-V10-EN
A start in this example shall only be possible if workpieces are
out of the monitored area of the light curtain
(MS_11…MS_22="0").
The information of the memory bit "COND" is read as memory
bit COND1 in the safety program. This allocation occurs in the
cyclic interrupt OB 35 for the following reason:
When reading data, which may be changed by the standard
user program or an operation control and monitoring system
during running of an F runtime group, from the standard user
program (memory bits or PAE of standard I/O), in the safety
program, it is necessary to use separate memory bits (here
COND1). Data from the standard user program have to be
written to these memory bits immediately before calling the F
runtime group. Only these memory bits may then be accessed
in the safety program.
In this example it has already been implemented. Generally,
however, the following applies:
Note
If the above section is not observed the F CPU may go to
STOP mode.
The failsafe program has the following program sequence:
F-Call
(FC1)
FC"Safety_Prg"
(FC10)
FB"L_CURTAIN"
(FB1,DB1)
FC"REINTEGRATION"
(FC2)
FB"F_MUTING"
(FB 189,DB 189)
From the
Distributed Safety
library
F-CALL (FC1)
F-CALL (FC 1) is the F runtime group and is called from the cyclic
interrupt OB (OB 35). F-CALL calls the F-programe block
(here the FC 10).
FC "Safety_Prg" (FC 10)
FC 10 ensures the modular setup of the safety program.
G_FB_XX_129