Rockwell Automation DeviceLogix System User Manual - Manual (Page 186)

186 Publication RA-UM003B-EN-P - February 2010
Appendix B RSNetWorx for DeviceNet Software and the DeviceLogix Editors
Understand Consumed Network I/O
(also known as Network Inputs)
Under normal conditions, an I/O device consumes data to apply to its
hardware outputs. DeviceLogix-enabled devices may consume
additional information to use in local logic.
An assembly is a collection of parameters from one or more objects.
The consumed I/O assembly for a device with digital outputs contains
the value parameters of the Discrete Output Point Objects
representing the hardware outputs present on the device. In other
words, the assembly is sent with the data to control the hardware
outputs on the device. Such an assembly for a module with 8 digital
outputs is shown in the Consumed I/O Assembly table.
When local logic is being used, DeviceLogix-enabled devices treat all
consumed I/O data as network inputs. That is to say that the device
may consume any amount of data, regardless of hardware, and treat it
as generic input from the network. By default, the first N Network
Inputs provide the data for the N hardware outputs found on the
device. However, if you bind the hardware output to some other
entity in the logic, the corresponding network input does not provide
the control for that output.
Each Network Input has a space reserved for it in the consumed I/O
assembly. The number of network inputs that a device consumes is
not directly associated with the number of hardware resources present
on the device. Therefore extra data can be sent to the module for use
in the local logic. One such assembly is shown below for the same
8-output device considered above.
Note that even though the device only contains 8 outputs, it is
consuming 16 bits of information. This gives you the option to map
additional information into the data that is sent to this device by the
master controller.
Consumed I/O Assembly
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Byte 0 Output
Value 7 Output
Value 6 Output
Value 5 Output
Value 4 Output
Value 3 Output
Value 2 Output
Value 1 Output
Value 0
Reserved Consumed I/O Assembly Bit
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Byte 0 Network
Input 7 Network
Input 6 Network
Input 5 Network
Input 4 Network
Input 3 Network
Input 2 Network
Input 1 Network
Input 0
Byte 1 Network
Input 15 Network
Input 14 Network
Input 13 Network
Input 12 Network
Input 11 Network
Input 10 Network
Input 9 Network
Input 8