Rockwell Automation 6008-SV2R VMEbus remote I/O Scanner - Manual (Page 43)

Chapter
Communicating with Remote I/O
4
4Ć6
If you need multiple updates to an I/O device during an I/O scan, enter a
logical address in the scan list more than one time. Do not assign the same
partial or full rack address to more than one channel in scanner mode.
Each channel must scan unique partial and/or full rack addresses.
The automatic configuration always displays the actual hardware
configuration, except for racks that have their global-rack inhibit bit set. In
this case, the global-rack bit overrides the automatic configuration.
Discrete I/O devices include such external devices as:
switches
relay
contacts
indicator lights
control relays
motor starters
A scanner channel exchanges discrete data (digital and analog) with remote
I/O node adapters like 1771-ASB modules via the scanner I/O image table
(Figure 4.3).
Figure 4.3
Remote I/O scan
adapter
adapter
adapter
Rack 3
Rack 2
Rack 1
data exchange
VME
master
processor
scanner
I/O table
The remote I/O scan is the time it takes for the scanner to
communicate with all of the entries in its scanĆlist once.
Design Tip
Processing Discrete I/O