943   control model change to "local" when TimeActivatedOperate is waiting

Created: 12 Nov 2012

Status: In Force (green)

Part: Part 7-2 (2010; Edition 2)

Links:

Page: P159, 161, 163, 164

Clause: 20. Control class model

Paragraph: Figure 38, 40, 41, 42

Category: Issue for edition 2 of this part

Issue

This issue rose up in one UCA testing meeting: what if a TimeActivatedOperate is waiting for timer expiration while the control mode of the control object is changed to local. e.g. by a "local/remote" toggle? It looks like in the standard the local/remote check, as operative check, is only checked once when receiving a TimeActivatedOperate command.
In normal case it's sufficient but in above case it will be potentially dangerous since the it may be an operator standing in front a real device expecting to do some manual operation. In which case the "local" operation shall have the highest priority and shall take effect immediately. i.e. the waiting TimeActivatedOperate shall be cancelled immediately to ensure personnel safety.

Proposal

TISSUE 783 has similar concern, but not consider above use case. Proposal: TimeActivatedOperate shall fail immediately when control of the object is changed to "local". i.e. the local/remote check shall be conduct every CPU calculation cycle.

Discussion Created Status
12 Apr 13 In Force (green)
I agree with Wolfgang. The operated test is repeated after the timer times out and before making the dynamic test.
As for change from remote to local while the dynamic test is being performed, there is no need to standardize what the expectation is, this is a policy/implementation issue. Checking the local remote state at the release signal of the synchhrocheck function can be considered as dynamic test also.
07 Jan 13 Discussion (red)
Not accepted. If you look into the control state diagrams, e.g. Figure 40, you see that the 'operative test' is repeated after the timer timeout before making the operation. State WaitForActivation is followed by state Performtest, similar to the normal Operate. 13 Nov 12 Discussion (red)

 

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