Allen-Bradley 1756 Series, User Manual, Page: 34 / 136

34 Rockwell Automation Publication 1756-UM013B-EN-P - October 2019
Chapter 1 Digital Safety I/O Module Operation in a Control System
These events occur when the controller sends data to a digital safety output
module.
1.
Data is sent in one of the following ways:
• If the controller is directly connected to the EtherNet/IP network, it
broadcasts data to the network.
In this case, skip to
step 3 .
• If the controller is connected to the EtherNet/IP network via a
communication module, the controller transmits the data to the
backplane.
In this case, proceed to
step 2 .
2.
The EtherNet/IP communication module transmits the data to the
EtherNet/IP network.
3.
The EtherNet/IP adapter in the remote system receives the data from the
network and transmits it to the system backplane.
4.
The remote output module receives the data from the backplane and
behaves as dictated by its configuration.
Remote Output Module to Controller Data Transmission
When a safety output module receives new data and the requested data value is
present on the RTB, the output module sends output readback status to the
controller. The data value corresponds to the signal present at its terminals.
In addition to the output readback, the output module sends other data to the
controller at the RPI. For example, the module alerts the controller if a short
circuit condition exists on the module.
The following events occur when a remote safety output module sends data to
the controller at the RPI.
1.
The module sends the data to the remote system backplane.
2.
The EtherNet/IP adapter in the system sends the data over the
EtherNet/IP network.
3.
One of the following:
• If the controller is directly connected to the EtherNet/IP network, it
receives the input data from the network without need for a
communication module.
• If the controller is connected to the EtherNet/IP network through
another communication module, the module transmits the data to its
backplane and the controller receives it.