Siemens S7-300 Installation And Operating Manual page 16

Product overview
1.2 Using Fail-Safe Signal Modules
Operation in safety mode with parameter setting "Keep last valid value" with digital output modules
You can only operate the SM 326; F-DO 10 x DC 24V/2A PP with parameter setting "Keep
last valid value" according to EN54-2/-4 or NFPA72. Configure safety mode in
STEP 7
module. The "SAFE" LED is lit when safety mode is active at the signal module.
For more information, refer to the chapter entitled " Reactions to Faults in Safety Mode
(Page 52) " and " Fault reactions in safety mode with parameter setting "Keep last valid
value" (Page 55) ".
Safety Integrity Levels supported
The fail-safe signal modules feature integrated safety functions for operation in safety mode.
The section below outlines the Safety Integrity Levels that can be achieved in safety mode
through assignment of the safety function parameters in
S7 Distributed Safety
sensors and actuators:
Table 1- 4
Safety Integrity Level in safety mode *
* Valid only if "Keep last valid value" was not set with parameters in digital output modules.
Enhanced availability in standard and safety mode
You can enhance availability by means of redundant operation of the F-SMs fail-safe signal
modules in
DO 10 x DC 24V/2A PP and SM 336; F-AI 6 x 0/4 ... 20 mA HART).
In safety mode
(with the exception of SM 326; DO 8 x DC 24V/ 2A PM).
Options of inserting redundant signal modules, depending on availability requirements (for
example configurations, refer to "Safety Engineering in SIMATIC S7, System Description
(http://support.automation.siemens.com/WW/view/en/37231510)"):
● Separately in two ET 200M distributed I/O devices
● In the same ET 200M distributed I/O device
Software requirements of redundant operation of F-SMs are described in the chapter
"Configuration and parameter assignment (Page 25)".
16
and using the address selector switch on the rear panel of the fail-safe signal
S7 F Systems
or
Safety Integrity Levels that can be achieved in safety mode
According to IEC 61508
SIL 2
SIL 3
standard mode
(exception: SM 326; DO 8 x DC 24V/2A PM, SM 326; F-
, you can operate the F-SMs redundantly in S7 F/FH Systems F-systems
STEP 7
, and by specific arrangement and wiring of the
According to EN 954-1
Category 3
Category 4
Installation and Operating Manual, 01/2010, A5E00085586-10
HW Config
using the optional package
According to
ISO 13849:2006
(PL) Performance Level d
(PL) Performance Level e
Fail-safe signal modules
of