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Diagnostic Address Discovery
WHO1001 supports discovering Devices through their native A/PL BUS addressing, independently of hardware-ID discovery through DIM13.
Two address-oriented mechanisms have been observed:
- querying a specific A/PL address;
- enumerating occupied addresses within an A area.
These mechanisms complement hardware-ID discovery:
Device Discovery
│
┌───────────┴───────────┐
│ │
Hardware ID BUS address
discovery discovery
│ │
DIM13 A / PL
│ │
▼ ▼
Physical Device Occupied address
Address discovery is particularly relevant to WHO1001, whose Devices use the Automation A/PL addressing model.
In the Automation domain, an address is composed of:
A = Area
PL = Point of Light / local point
The two values are represented together in the diagnostic WHERE.
For example:
A = 0
PL = 1
WHERE = 01
Address discovery operates on this native BUS-address space rather than on the Device hardware ID.
MyHOME Suite can directly query a specific A/PL address.
For example, the observed query for A=0, PL=1 is:
*#1001*01*0##
Here:
WHO = 1001
WHERE = 01
WHAT = 0
If a Device occupies the requested address, it responds with diagnostic information associated with that address.
This provides a direct method for testing whether a particular A/PL address is occupied.
MyHOME Suite can also enumerate occupied addresses within an A area.
Observed requests include:
*#1001*00*1##
for A=0, and:
*#1001*1*1##
for A=1.
These requests cause Devices at occupied addresses within the requested area to respond.
Conceptually:
Request area A
│
▼
Scan address space
│
├── occupied PL → Device response
├── occupied PL → Device response
│
└── ...
This differs from sending an individual direct query for every complete A/PL address.
An occupied address can respond with DIM1.
For example:
*#1001*01*1*107*6*6*8##
This identifies a Device responding at WHERE=01.
The DIM1 values provide its catalogue identity signature:
| Field | Interpretation |
|---|---|
VALUE1 |
AS_ITEM_SYSTEM.modobj |
VALUE2 |
Unknown |
VALUE3 |
EN_BRAND.brand_modobj |
VALUE4 |
EN_LINE.line_modobj |
The response therefore provides both an occupied BUS address and information that can be used to classify the responding Device.
Address discovery and hardware-ID discovery answer different questions.
Hardware-ID discovery uses DIM13:
*#1001*0*13##
Its purpose is to enumerate physical Devices by their unique hardware identifiers.
The result identifies:
Physical Device
│
▼
Hardware ID
This mechanism can find Devices independently of knowing their configured A/PL address.
See Diagnostic Device Discovery.
Address discovery instead starts from the BUS topology:
A / PL address
│
▼
Occupied?
│
▼
Responding Device
It therefore identifies which diagnostic addresses are currently represented on the BUS.
The two discovery mechanisms are complementary rather than interchangeable.
A hardware ID identifies a physical Device, while an A/PL address identifies a position in the Automation BUS addressing model.
These concepts should not be treated as equivalent:
Physical Device
│
├── Hardware ID
│
└── Module structure
│
└── BUS addresses
A single physical Device can expose multiple logical Modules, and those Modules can potentially use different intrinsic A/PL addresses.
Consequently, the relationship between a Device and an address is not necessarily one-to-one.
Address discovery operates on diagnostic WHERE values visible on the BUS.
DIM32, by contrast, reports the intrinsic configured address of a particular Module/Object where that function possesses one.
Conceptually:
Address discovery
│
▼
Diagnostic WHERE
│
▼
Responding Device
versus:
Device
│
▼
Module
│
▼
DIM32
│
▼
Intrinsic Module address
These values can coincide, but they represent different layers of the protocol model.
A Device containing several addressable Modules may expose more than one intrinsic address even though it remains a single physical Device with one hardware ID.
See Module Addressing and DIM32.
Hardware-ID discovery provides a hardware ID that can subsequently be used to select a Device directly:
DIM13 discovery
│
▼
Hardware ID
│
▼
WHAT10#ID
│
▼
Device interview
Address discovery provides an alternative route based on the configured BUS topology:
A / PL discovery
│
▼
Occupied WHERE
│
▼
Address-based diagnostic interaction
The two mechanisms therefore provide different entry points into the same diagnostic architecture.
See Diagnostic Device Interview.
The observed address-discovery mechanism belongs to WHO1001.
This is significant because A/PL addressing is characteristic of the Automation topology handled by this diagnostic domain.
Other diagnostic domains use different addressing models and should not be assumed to support the same address-discovery syntax.
For example:
WHO1001
│
▼
Automation diagnostic domain
│
▼
A / PL topology
│
▼
Address discovery
The existence of a common hardware-ID discovery mechanism across several diagnostic WHO domains does not imply that their native address-discovery mechanisms are identical.
The observed mechanisms allow MyHOME Suite to approach the installation from two directions.
Enumerate hardware IDs
│
▼
Identify physical Devices
│
▼
Interview Device by ID
This approach is independent of the Device's configured A/PL topology.
Enumerate / query A/PL
│
▼
Identify occupied addresses
│
▼
Interact through BUS topology
This approach starts from the configured Automation address space.
Using both strategies allows MyHOME Suite to reconstruct both the physical Device inventory and the logical BUS topology.
The currently observed WHO1001 address-discovery operations can be summarized as:
| Operation | Example |
|---|---|
| Query specific A/PL | *#1001*01*0## |
Enumerate A=0
|
*#1001*00*1## |
Enumerate A=1
|
*#1001*1*1## |
The exact internal semantics of the WHAT values used by these request forms should be derived from observed behavior rather than generalized beyond the tested WHO1001 context.
Address discovery forms the bridge between physical Device discovery and the Automation BUS topology:
WHO1001
│
┌────────┴────────┐
│ │
Hardware-ID discovery Address discovery
│ │
▼ ▼
Physical Devices A/PL topology
│ │
└────────┬────────┘
▼
Device interview
│
▼
Module / Object model
│
▼
Configuration
This distinction is important for Devices containing multiple logical Modules because a physical Device identity and its configured BUS addresses describe different aspects of the installation.