Allen-Bradley GuardLogix 5570

Rockwell Automation Publication 1756-UM022D-EN-P - May 2017 15
System Overview Chapter 1
HMI Devices
HMI devices can be used with GuardLogix controllers. HMI devices can
access standard tags as with a standard controller. However, HMI devices
cannot write to safety tags; safety tags are read-only for HMI devices.
Controller Data-flow
Capabilities
This illustration explains the standard and safety data-flow capabilities of the
GuardLogix controller.
Figure 1 - Data-flow Capabilities
No. Description
1 Standard tags and logic behave the same way that they do in the standard Logix platform.
2 Standard tag data, program- or controller-scoped, can be exchanged with external HMI devices, personal
computers, and other controllers.
3 GuardLogix controllers are integrated controllers with the ability to move (map) standard tag data into
safety tags for use within the safety task.
ATTENTION: These data must not be used to control a SIL 3/PLe output
directly.
4 Controller-scoped safety tags can be read directly by standard logic.
5 Safety tags can be read or written by safety logic.
6 Safety tags can be exchanged between safety controllers over Ethernet or ControlNet™ networks, including
1756 and 1768 GuardLogix controllers.
7 Safety tag data, program- or controller-scoped, can be read by external devices, such as HMI devices,
personal computers, or other standard controllers.
IMPORTANT
Once this data is read, it is considered standard data, not SIL 3/PLe data.
Standard Safety
Standard Tasks
Safety Task
Safety Programs
Standard Programs
Standard Routines
Program Data
Program Safety Data
Safety Routines
Controller Standard Tags
Controller Safety Tags
GuardLogix Controller