Rockwell Automation 2100-GK61 DeviceNet to SCANport - Manual (Page 113)

Publication 2100-UM001B-EN-P – January 2001
Using DeviceNet Explicit Messaging 6-21
In this example, there were four entries in the fault queue. Notice the
following about the data:
Refer to Appendix C, DeviceNet Objects, for more information on
object descriptions.
Using Messages to Control
SCANport Products Explicit messages provide multi-purpose, point-to-point
communication paths between two devices. It is possible to control
SCANport devices through explicit messaging on DeviceNet by
following particular guidelines and by writing to various register
objects that are buffering the I/O data. The guidelines are as follows:
• The adapter cannot be allocated by a master/scanner in order to
allow explicit writes to the register object.
• Write access to any register object within the adapter will not be
allowed if the message is passed through a connection whose
expected packet rate (EPR) is zero.
• The adapter is required to mark any explicit connection after
allowing a write to a register object through it.
• If a marked explicit connection times out based on the EPR, then
the I/O fault action will be that configured for Communication
Loss over the I/O connection.
• If a marked explicit connection is deleted, then the I/O fault
action will be that configured for Idle over the I/O connection.
• Multiple explicit connections can write/overwrite the control I/O
if they meet the guidelines specified. Each connection will need
to be marked individually within the adapter.
• If the adapter gets allocated/re-allocated by a controller such that
valid I/O data is being sent to the adapter, 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
Location Value Meaning
N20:10 0x0201 TXID of 2. Command 1 (Execute)
N20:11 0x0006 Port 0. Size = 6 bytes (N30:3 – 5)
N20:12 0x0E03 Service E (Get Attribute Single) Node 3
N20:13 0x0097 SCANport Pass-Through Fault Object
N20:14 0x0000 Instance 0 (Class Access)
N20:15 0x0001 Attribute 1 (Number of Fault Queues)
N20:50 0x0201 TXID of 2. Status 1 (Success)
N20:51 0x0006 Port 0. Size = 6 bytes (N30:3 – 5)
N20:52 0x8E03 Service 8E (Get Attribute Single
Response)
N20:53 0x0004 4 fault queues