Rockwell Automation 1756-HSC ControlLogix High Speed Counter Module - Manual (Page 57)

Rockwell Automation Publication 1756-UM007C-EN-P - November 2011
Configure the 1756-HSC Module 57
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 faults in the data area associated with
the module. The RSLogix 5000 programming software may monitor this data
area to announce the module’s failures.
Local Chassis Operation
The time frame that a module produces its data depends on the options
chosen during configuration and where in the control system the module
physically resides, such as locally or remotely. The requested packet interval
(RPI) instructs the module to send its channel and status data to the local
chassis backplane at specific time intervals.
Remote Chassis Operation
If a module resides in a networked chassis, the role of the RPI changes slightly
with respect to getting data to the owner. The RPI not only defines when the
module produces data within its own chassis, but also determines how often
the owner-controller receives it over the network.
When an RPI value is specified for a module in a remote chassis, in addition to
instructing the module to produce data within its own chassis, the RPI also
‘reserves’ a spot in the stream of data flowing across the network.
IMPORTANT
The RPI value is set during the initial module configuration by
using the RSLogix 5000 programming software. This value can
be adjusted when the controller is in Program mode.
See page 64 for RPI settings.