Rockwell Automation 1785-L20C_L40C, D17856.5.14 ControlNet PLC-5 Programmable Controllers User Manual - Manual (Page 30)

Chapter 2
Planning to Use Your ControlNet
PLCĆ5 Processor
2-2
A similar method is used for all scheduled data-transfer operations.
Housekeeping
Program Scan
DataĆ
Table
Files
Scheduled Data Transfer
Private
Memory
Buffers
Scheduled Data
Transfers
Data Update
Logic Scan
The following scheduled data-transfer operations are supported by the
PLC-5/20C and -5/40C processors on a ControlNet network:
Table 2.A
ControlNet Scheduled DataĆTransfer Operations
Operation Description
Discrete I/O Data Transfer Performed in a deterministic and repeatable manner
asynchronous to and independent of the ladderĆlogic
program scan. You configure all ControlNet discrete I/O
data transfers on a perĆnode basis in the I/O map table. ①
NonĆdiscrete I/O Data Transfer Handled with the same priority as discrete I/O data transfer.
You can update analog data without using blockĆtransfer
instructions in ladder programs. You do this by including
nonĆdiscrete I/O dataĆtransfer configurations in the I/O map
table. This data is updated in the buffers and dataĆtable
files between logic scans in the same manner as that used
in discrete I/O data transfer. ①
PeerĆtoĆpeer Communication Allows the controlling" processor at network address 01
to communicate with other ControlNet processors on the
ControlNet network with the same priority as that of the
discrete and nonĆdiscrete I/O data transfers discussed
above. ①
① While scheduled data transfer is asynchronous to program scanning, all data is presented
synchronously to the processor and output buffers during housekeeping.