1793 Behaviour of output contacts when LN is in blocked mode
- Created
- 28 Sep 2021
- Status
- Discussion (red)Open for discussion while the solution is worked out. Any signed-in reader may comment. Show the workflow
- Part
- Part 7-4 (2020; Edition 2.1)
- Links
- None
- Page
- 397
- Clause
- Annex A
- Paragraph
- Table A.1
Issue
This request for clarification deals with s/c "boundary" Logical Nodes which are connected to the process.
As soon as the mode of such LN is set to "blocked", "test/blocked" respectively, no (wired) output data (digital by relays or analogue setpoints) will be issued to the process.
It is not defined whether
the concerned outputs shall turn to their idle/default states or
the status of the concerned outputs shall be frozen in the present value.
Proposal
Consider transient and non-transient controls.
Proposal (for contacts):
-For transient controls the contact to assume its default position (open if normally open and closed if normally closed). Allow to finalize a control in progress at the time of activating "blocked" or "test/blocked" mode to prevent from intermediate equipment positions.
- For non-transient controls the contact to remain in its state.
| Discussion | Created |
|---|---|
| Discussion (red) The wording of the new statement which will be added shall refer to both digital outputs and analogue outputs. | 28 Jul 26 |
| Discussion (red) follwing the discussions within WG10 incl. TF 10-3, I propose to change the state to 'Approval (Future Improvement)' | 28 Jul 26 |
| Discussion (red) See also discussion in redmine DB --> https://redmine.ucaiug.org/issues/6555 | 07 Feb 24 |
|
Discussion (red)
Blocked mode should de-energize the output relays.
Reason for that: Blocked mode can be used before restarting a device when uploading a configuration. The new configuration may associate the digital output differently than current configuration. Therefore "de-ernergizing" sounds like a deterministic safe state for the command to the output relays, regardless if the relays is being used for non-transient control or not. |
21 Nov 23 |
|
Discussion (red)
Agree to add a line in Table A.2 and to complement the wording in Table A.1.
items to consider in the new statement: - binary outputs (contacts) - analogue outputs (current loops) - LPDO LN class in preparation - external DO connected via bus (intelligent terminals, intelligent breaker units, e.g.) |
04 Oct 21 |
|
Discussion (red)
Just a correction of wording: we should use the terms like in part 7-3: persistent output and pulse output (OutputSignalKind).
We may consider a formal change in table A.2 of 7-4 or adding a row to distinguish "output to process" from software and relay output (self-holding relay). |
01 Oct 21 |
| Accepted Tissue accepted and open for discussion. | 29 Sep 21 |