Safety task signature, Hmi devices – Rockwell Automation 1756-L7x GuardLogix 5570 Controllers User Manual
Page 12
12
Rockwell Automation Publication 1756-UM022A-EN-P - November 2012
Chapter 1
System Overview
Safety Task Signature
The safety task signature consists of an ID number, date, and time that uniquely
identifies the safety portion of a project. This includes safety logic, data, and
configuration. The GuardLogix system uses the safety task signature to
determine the project’s integrity and to let you verify that the correct project is
downloaded to the target controller. Creating, recording, and verifying the safety
task signature is a mandatory part of the safety-application development process.
See
Generate a Safety Task Signature on page 96
for more information.
Distinguishing between
Standard and Safety
Components
Slots of a GuardLogix system chassis not used by the safety function may be
populated with other ControlLogix modules that are certified to the Low
Voltage and EMC Directives. Refer to
to
find the CE certificate for the Programmable Control–ControlLogix Product
Family and determine which modules are certified.
You must create and document a clear, logical, and visible distinction between the
safety and standard portions of the controller project. To aid in creating this
distinction, the Logix Designer application features safety identification icons to
identify the safety task, safety programs, safety routines, and safety components.
In addition, the Logix Designer application uses a safety class attribute that is
visible whenever safety task, safety programs, safety routine, safety tag, or safety
Add-On Instruction properties are displayed.
The controller does not allow writes to safety tag data from external HMI devices
or via message instructions from peer controllers. The Logix Designer
application can write safety tags when the GuardLogix controller is
safety-unlocked, does not have a safety task signature, and is operating without
safety faults.
The ControlLogix Controllers User Manual, publication
,
provides information on using ControlLogix devices in standard (non safety)
applications.
HMI Devices
HMI devices can be used with GuardLogix controllers. HMI devices can access
standard tags just as with a standard controller. However, HMI devices cannot
write to safety tags; safety tags are read-only for HMI devices.