1752   Inconsistency in LPHD requirements

Created: 02 Feb 2021

Status: Discussion (red)

Part: Part 7-1 (2020; Edition 2.1)

Links:

Page: ~70

Clause: 8.2.3

Paragraph: 7

Issue

Logical devices that do not mirror logical devices of other physical devices shall provide a LPHD that represents the physical device on which they reside. In Figure 49, this logical device is PXY_GTW_LD1, which shall be implemented to represent the information about the proxy/gateway itself. The logical nodes LLN0 and LPHD of this logical device shall represent information about the proxy/gateway device. The logical device may also contain domain specific logical nodes


First sentence is inconsistent and in correct. For example 8.2.1 says:
The logical node physical device (LPHD) represents common data of the physical device hosting the logical device. LLN0 shall be defined in every logical device while LPHD shall be defined in at least one logical device.

Proposal

Change shall to may:

Logical devices that do not mirror logical devices of other physical devices may provide a LPHD that represents the physical device on which they reside.

As the LPHD represents the physical device, if there is more than one instance the data must be consistent in all.

Discussion Created Status
move to discussion 01 Feb 22 Discussion (red)
move to accepted 01 Feb 22 Accepted
Requesting the data to be consistent for all LHPD within a physical device, does not mean that all LPHD are duplicated/copied.
The DataObject is of relevance: LPHD.Sim shall. when present multiple time, have the same value over all LPHDs of a physical device. Same for PhyHealth.
But Product Standard LPHD extensions may only be present in the logical device (not even a root one) that implements the product standard requirement (not copied).



03 Feb 21 Triage
I agree in principle with the hierarchy providing one LPHD at the root LD, but to say that "It is clear that all logical devices shall provide a LPHD." assumes that "child LDs" are not LDs in this context, no? Perhaps you are meaning "it is clear that all physical devices shall provide an LPHD"?


The example in 8.2.1 (fig. 47) demonstrates that the "SYS" LD does not have an LPHD. What would be the use case for requiring duplication of the LPHD here?

Agree that the sentence about consistency belongs in 8.2.1. Perhaps:

The logical node physical device (LPHD) represents common data of the physical device hosting the logical device. LLN0 shall be defined in every logical device while LPHD shall be defined in at least one logical device, and if multiple LDs instantiate the LPHD the data must be kept consistent across all copies.


03 Feb 21 Triage

 

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