Rockwell Automation DeviceLogix System User Manual - Manual (Page 68)

68 Publication RA-UM003B-EN-P - February 2010
Chapter 3 Bind Function Blocks with I/O
Overview of Inputs and
Outputs Function blocks contain both inputs and outputs. Inputs to function
blocks can be attached to any of the input types or to the output of
another function block. Only one connection can be made to one
function block input pin and an input cannot be tied to another input.
Outputs from function blocks can be attached to either hardware or
network outputs or to the inputs of other function blocks. A single
function block output can be the source of (and connected to) any
number of hardware outputs or function block inputs. Hardware
outputs cannot be tied to other hardware outputs, and hardware
inputs cannot be tied to other hardware inputs.
Inputs
Device inputs can connect to any function block input or can drive an
output directly. The number and type of inputs varies from device to
device. However, devices may support the following five types of
inputs (supported categories based on device) and are described
below.
Input Category Description
Hardware (physical) Hardware inputs represent the actual inputs (such as sensors and
switches) attached to a particular device.
Network Network inputs represent data sent from a master that can be
used in the device’s logic.
Status Status inputs indicate the state of the device. For example, if an
explicit message connection exists between the device and a
master, an ’Explicit connection exists’ input would be set to true,
possibly impacting the logic that the device performs.
Fault Fault inputs are conditions that report device errors. For example,
if a device detects a short circuit on an output, it can set a fault
input to true. The fault input can then impact the logic that the
device performs.
Note: Currently, faults can be of the Boolean type only which
indicates a device fault status, while the other input types can be
Boolean or Analog.
Miscellaneous Miscellaneous inputs reflect a status or a condition that is
specific to each individual product.