Siemens SIMATIC S7-1200

Getting started
2.3 Programming
S7-1200 Functional Safety Manual
46 Manual, 02/2015, A5E03470344-AA
2.3
Programming
2.3.1
Introduction
In this example, a fail-safe function block (F-FB) will be programmed with a safety door
function, an emergency stop function (safety circuit for switch-off in case of emergency stop,
open safety door, or someone entering the protected area monitored by the laser scanner), a
feedback circuit (as protection against reclosing in case of faulty load), a user
acknowledgement for reintegration, and indirect switching of a motor using two contactors.
The programmed F-FB will then be compiled to form a safety program and downloaded to
the fail-safe CPU.
Fail-Safe SM data blocks (F-IO DBs)
An F-IO DB is automatically generated when you add a fail-safe SM to your configuration.
The F-I/O DBs generated for the example I/O are located in the "Project tree" in the
"Program blocks", "System blocks" folder:
①
"F00008 F-DI16 [DB30002]": Fail-safe digital input SM 1226 F-DI 16 x 24 VDC data block (DB)
②
"F000016 F-DQ4 [DB30003]": Fail-safe digital output SM 1226 F-DQ 4 x 24 VDC data block
(DB)