Rockwell Automation 1756-XXXX ControlLogix Analog I/O Modules - Manual (Page 23)

Publication 1756-UM009C-EN-P - December 2010 23
Analog I/O Operation in the ControlLogix System Chapter 2
3. After running RSNetWorx software, perform an online save of the
RSLogix 5000 project so the configuration information that
RSNetWorx software sends to the controller is saved..
Direct Connections ControlLogix analog I/O modules use direct connections only.
A direct connection is a real-time data transfer link between the controller and
the device that occupies the slot that the configuration data references. When
module configuration data is downloaded to an owner-controller, the
controller attempts to establish a direct connection to each of the modules
referenced by the data.
If a controller has configuration data referencing a slot in the control system,
the controller periodically checks for the presence of a device there. When a
device’s presence is detected there, the controller automatically sends the
configuration data, and one of the following events occurs:
• If the data is appropriate to the module found in the slot, a connection
is made and operation begins.
• If the configuration data is not appropriate, the data is rejected and an
error message displays in the software. In this case, the configuration
data can be inappropriate for any of a number of reasons.
For example, a module’s configuration data may be appropriate except
for a mismatch in electronic keying that prevents normal operation.
The controller maintains and monitors its connection with a module. Any
break in the connection, such as removal of the module from the chassis while
under power, causes the controller to set fault status bits in the data area
associated with the module. The RSLogix 5000 programming software
monitors this data area to annunciate the module’s failures.
IMPORTANT
You must run RSNetWorx for ControlNet software whenever a
new I/O module is added to a scheduled ControlNet chassis.
When a module is permanently removed from a remote chassis,
we recommend that you run RSNetWorx for ControlNet
software to reschedule the network and optimize the allocation
of network bandwidth.