Rockwell Automation 2098-IPD-020-DN Ultra5000 Series Intelligent Positioning Drives with DeviceNet Reference Manual - Manual (Page 39)

Publication 2098-RM002A-EN-P – October 2001
Programming Reference 4-15
Select, Parameter 8 is set to 0 (No data consumed), or if you configure
the drive to ignore Array Index 3 – DeviceNet Idle Fault Action by
setting the DNetConfigData array to 1 (Ignore).
Using Explicit Messaging to Control the Ultra5000
Explicit messages provide multi-purpose, point-to-point
communication paths between two devices. It is possible to control
the drive through explicit messaging on DeviceNet by following
particular guidelines and by writing to various Assembly Objects that
are buffering the I/O data. Although it is possible to control the drive
by writing to various parameter objects, you should consider using a
user program interfacing with the Assembly Objects for controlling the
drive. The guidelines are as follows:
• Write to the various Assembly Objects that are buffering the I/O
data.
• Write access to any Assembly Object is not allowed if the message
is passed through a connection whose expected packet rate (EPR)
is zero or if I/O data is being sent over an I/O messaging
connection.
• The drive marks any explicit connection after allowing a write to
an Assembly Object through the connection.
• If a marked explicit connection times out based on the EPR, then
the fault action will be that for Communication Loss over the I/O
connection, using Array Index 4 – DeviceNet Comm Fault Action of
the DNetConfigData array.
• If a marked explicit connection is deleted, then the fault action will
be that configured for Idle over the I/O connection, using Array
Index 3 – DeviceNet Idle Fault Action of the DNetConfigData array.
• Multiple explicit connections can write/overwrite the control I/O if
they meet the guidelines specified. Each connection will be
marked individually within the drive.
• If the drive gets allocated/re-allocated by a controller such that
valid I/O data is being sent to the drive, or if an Idle condition
from the allocating controller is transitioned back to valid data,
then all marked explicit connections will be reset to unmarked and
future writes blocked.
• If a marked connection has its EPR value reset to zero (0) after
being marked, then the connection will become unmarked.