Rockwell Automation 1785-L20C_L40C, D17856.5.14 ControlNet PLC-5 Programmable Controllers User Manual User Manual
Page 38
Chapter 2
Planning to Use Your ControlNet
PLCĆ5 Processor
2-10
Description
MapĆTable Entry Field
Input File and Size
This is the offset in the input file where the data is to be stored and the number of words to be received from
the input device.
For discrete I/O data transfer, the offset is into the inputĆimage table; for nonĆdiscrete I/O
data transfer or peerĆtoĆpeer communication with another ControlNet processor, the offset is into the Data Input
File entered on the ControlNet configuration screen. Scheduled peerĆtoĆpeer inputs can also use the
inputĆimage file.
Output File and Size
This is the offset in the output file where the data is located and the number of words of the output transfer.
For discrete I/O data transfer, the offset is into the outputĆimage table; for nonĆdiscrete I/O data transfer or
peerĆtoĆpeer communication with another ControlNet processor, the offset is into the Data Output File (DOF)
entered on the ControlNet configuration screen. Scheduled peerĆtoĆpeer outputs can also use the
outputĆimage file.
Status File Offset
This is an offset in a status file that points to three words of information on the status of this mapĆtable entry.
Configuration File and Size
Used only in 1771 nonĆdiscrete I/O data transfer and 1794 configurations, this is the offset in a configuration
file where configuration information needed for this node is located and the size in words of the information.
Discrete I/O DataĆTransfer Mapping
Regardless of the type of I/O—e.g., 1771, 1794—all ControlNet discrete
I/O data is stored within the processor’s I/O image files according to the
corresponding I/O map-table entry. Any status information transferred
along with the I/O data is stored in a separate status file that you specify
during configuration.
NonĆdiscrete I/O DataĆTransfer Mapping
All ControlNet non-discrete I/O data is stored in integer files that you
specify in a ControlNet configuration screen. The ControlNet processor
supports two distinct image files; both are integer data-table files that
you specify:
Data Input File (DIF)
Data Output File (DOF)
Each map-table entry for a non-discrete I/O data transfer defines an offset
into the DIF or DOF where the data is stored. Using separate data-table
files for non-discrete I/O data transfer allows the processor to present
non-discrete I/O data in the same way as discrete I/O data—continuously
transmitted and asynchronous to the ladder-logic program scan.
1771 Modules
ControlNet 1771 discrete I/O data-transfer mapping requires one map-table
entry per module. ControlNet 1771 non-discrete I/O data-transfer mapping
requires one or two map-table entries per module, depending on the
module type.
The PLC-5/20C and -5/40C ControlNet non-discrete I/O data-transfer
mechanism makes it possible to eliminate block-transfer programming to
communicate with the 1771 modules listed in