Figure 11: Sensor Packets Logical Reference Model - Honeywell ISA100 Gen X User Manual

0, the Radio TLDE understands that this is a local packet being sent to this device. The TLDE
then changes the direction of the packet from Tx to Rx and sets the return network address
pointer to NULL. Since the Rx and Tx packets are maintained in the same queue, the APDU
need not be moved. You can modify only the ASL queue header of the Sensor packet.
The NULL return address for APDU requests is mapped to the contract ID 0 (local packets).
This means that for the response to an APL, read request to the DMAP is placed into the ASL
queue using contract ID 0. When the TLDE flushes the contract ID 0 from the ASL queue, it is
converted to an ASL indication and it is sent to the Sensor board when it acquires its priority
APDU.
ASL Queued Packet Types
The ASL queued class of packets supports three packet types: Request, Confirm, and
Indication.

Figure 11: Sensor packets Logical Reference Model

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Release Independent
ISA100 Gen X Radio Module User's Guide
April 2018
Honeywell