246   Control negative response

Created: 28 Oct 2005

Status: In Force (green)

Part: Part 8-1 (2004)

Links:

Page: Table 69

Clause: 20

Paragraph: 3

Category: Issue may impact interoperability of implementations of Edition 1

Issue

Part 8-1 table 69 defines "informationreport (LastApplError)" for Cancel and Operate response- services.

If the ctlModel = "Direct-operate with normal security" should the IED
also send the Operate response- informationreport (LastApplError)?
And if the ctlModel = "SBO-operate with normal security" should the IED also send the Cancel response- informationreport (LastApplError) ?

From my point of view the informationreport (LastApplError) is only
applicable for "enhanced security" control.

Proposal

Add a note 5) for the mentioned information report into table 69 "only applicable for enhanced security"

Discussion Created Status
11 Dec 08 In Force (green)
In principle, there is agreement to add AddDiagCause to the OperateResponse-.

However, in order to provide backward compatibility to Edition 1 implementation,, the additional information report will be made OPTIONAL. Additionally, it must be sent prior to LastApplError. 		26 Mar 08 Ballot Period
I aggree with Thierry, moreover LastApplError is a spontaneous report from the server to indicate additional information if needed.
In case of direct-operate, if the server has no significant information to send, why oblige to send one?
Hence, and for major backward compatibility too, this should be let on the server decision (eventually described in PIXIT). 		21 Aug 07 Ballot Period
The final proposal below does not meet the real problem. As already stated in the discussion, the LastApplError is not only used for the CmdTerm message, but also to send the AdditionalCauseDiagnostic on a negative response to the Operate. Therefore, it should be sent also in a negative response to the Operate given with normal security. The only reason not to change anything is backward compatibility with 8-1 clause 20.7.3.1, although this contradicts 7-2. 15 May 07 Ballot Period
According to 7-2 clause 17.2
"In the case of control with normal security there shall be no additional supervision of the status value by the control object. This means that for the negative case, if the status value did not change to the control value, the client will not get information about the failure from the control object."

For backwards compatibility, normal security shall remain without LastAppError
15 May 07 Ballot Period
changed to blue 02 Dec 05 Not Applicable
From my point of view an AddCause can apply to all control models. Typical examples are 'Command-already-in-execution', 'blocked-by-mode' and some other blocking causes, which apply to all command models and should also be given as additional information to the negative acknowledgement. So, no action is needed - except may be to clarify that the LastApplError has to come with all negative acknowledgements on command requests. 10 Nov 05 Discussion (red)

 

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