Rockwell Automation 6008-SV2R VMEbus remote I/O Scanner - Manual (Page 87)

Chapter
Operating in SVĆSuperset Mode
6
6Ć6
These bits: Considerations:
bits 0-2 These bits specify the programming mode of the scanner. These bits are mutually
exclusive - the scanner can be in only one of these modes.
bit 3 If the debug mode bit is set by the scanner, the scanner cannot be shutdown by the
internal watchdog.
ATTENTION: Unwanted machine motion can result from disabling the VME master
processor watchdog. Only use the debug mode when you are debugging the application
program for the VME master processor.
bit 4 The scanner sets bit 4 when it detects an unsolicited block transfer. An unsolicited block
transfer results if a VME master processor accidentally writes discrete information to an
output image table byte that is mapped to an I/O slot requiring a block transfer.
When this bit is set, take action to correct this situation because it can seriously degrade
scanner response time. The scanner can only set this bit; the VME master processor
must clear it.
bit 5 If bit 5 is set, the scanner has at least one block transfer request in its internal queue.
When the associated block transfer is completed and the queue is empty, the scanner
will clear the bit.
bit 6 If bit 6 is set, at least one adapter has faulted, lost power, or has been dropped from the
I/O link. The VME master processor can issue the LINK STATUS command for fault
details. When all the adapters in the scan list are cleared of faults or have been brought
back on line, the scanner will clear this bit.
bit 7 If bit 7 is set, an adapter's operating status has changed. The scanner uses this bit to
tell VME master processors of a change in status of one of the adapters on the I/O link.
An example is that if an operator temporarily pulled the swing arm from an adapter, the
scanner would lose communications with that adapter. Maybe the operator could quickly
put it back and the status LED and the adapter fault bit (bit 6) would say everything is
working properly, but the adapter fault change bit would be left set, indicating that an
adapter was temporarily off line. A VME master processor can issue the LINK STATUS
command to make sure the I/O link and all adapters are operating properly upon seeing
this bit set. Only the scanner can set this bit. The VME master processor must clear it.