Device Reset And Remote Output Reset Considerations - Allen-Bradley 1747-SN User Manual

Device Reset and Remote
Output Reset
Considerations
Scanner Configuration and Programming
The 1747-SN Scanner Device Reset words (M0:e.16 to M0:e.19) and
the Remote Output Reset words (M0:e.24 to M0:e.27) operate in
conjunction with each RIO device to determine the state of that RIO
device's outputs. The output control information that the scanner
sends to the RIO device depends on how you configure these bits.
The RIO device acts on the output control information in accordance
with its functionality and configuration. To fully understand how a
specific device responds to the Device Reset and Remote Output
Reset words, you must determine the operation of the RIO device.
To determine RIO device output operation, refer to that device's user
manual.
ATTENTION: When using the Device Reset and
Remote Output Reset words, you must completely
!
understand and fully test all device output operations
before beginning normal system operation.
To properly use the Device Reset and Remote Output Reset words,
you must consider the output control information sent to the devices
during two SLC processor operating conditions:
The SLC processor is in any given mode (Run, Program, Test, or
Fault).
The SLC processor is leaving any mode and entering another.
If you do not modify the Device Reset and Remote Output Reset
words, the device outputs reflect the scanner output image whenever
the SLC processor is in Run mode. If the SLC processor is in
Program, Test, or Fault mode, it instructs the device to reset its
outputs.
If you modify the default settings, the Device Reset and Remote
Output Reset words change. The table on the following page
contains examples of what changes occur. We base the information
in the table on the assumption that the scanner's slot is always
enabled and the RIO link device is communicating with the scanner.
To determine how the Device Reset and Remote Output Reset words
operate, locate the box where the row and column are headed by the
modes in question. The shaded boxes represent the Device Reset
and Remote Output Reset word operation while in that mode.
4–19
Publication 1747 6.6 - July 1996