Rockwell Automation 1756-IF4FXOF2F ControlLogix High-speed Analog I/O Module - Manual (Page 140)

140 Rockwell Automation Publication 1756-UM005B-EN-P - January 2013
Appendix E Module Operation in a Remote Chassis
Worst Case RPI Scenario
In the worst case scenario, the controller sends the data just after the reserved
network slot has passed. In this case, the data is not received by the module until
the next scheduled network slot.
Use RSNetWorx Software and
Logix Designer Application The I/O configuration portion of the Logix Designer application generates the
configuration data for each high-speed analog I/O module in the control system,
whether the module is located in a local or remote chassis. A remote chassis
contains the module but not the module’s owner-controller.
You must use the configuration dialog boxes in the application to configure the
module. Configuration data is transferred to the owner-controller during the
program download and subsequently transferred to the appropriate modules in
the local chassis. However, you must run RSNetWorx for ControlNet software to
enable modules in the remote chassis.
When you run the software, it transfers configuration data to remote modules
and establishes a Network Update Time (NUT) for the ControlNet network.
The NUT is compliant with the desired communication options specified for
each module during configuration. Anytime a controller references an I/O
module in a remote chassis, you must run RSNetWorx software to configure the
ControlNet network.
Follow these steps when configuring high-speed analog I/O modules in a remote
chassis.
1. Configure all modules for the controller.
2. Download configuration information to the controller.
3. Run RSNetWorx for ControlNet software.
IMPORTANT These Best and Worst Case scenarios indicate the time required for output data
to transfer from the controller to the module once the controller has
produced it.
They do not take into account when the module will receive NEW data
(updated by the user program) from the controller. That is a function of the
length of the user program and its asynchronous relationship with the RPI.
IMPORTANT You must run RSNetWorx for ControlNet software whenever a new module is
added to a remote chassis. When a module is permanently removed from a
remote chassis, we recommend that you run RSNetWorx software to optimize
the allocation of network bandwidth.