Cannot login-Reservation of Controller failed

During getting online is shown message "Warning! Reservation of Controller failed. THe application/controller cannot be downloaded. Download not possible since the following controllers are stopped or occupied" The controller is neither stopped not occupied (or at least not actively - I cannot know if the last connection was correctly finished or not). How can I get rid of this? Possible without restarting PLC?
Thanks.
Tomas Fibir

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fibirt Rank: 1270

Asked 18 days ago

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Boot the engineering station and refresh project
Check Control Builder Session Logs
Right Click Controllers and "Show Remote Systems" - Check the loaded applications
Check the controller logs
Can the OPC Servers save the cold retain values ?
Can you go online without download ?
Have you physically checked the LEDs on the controller ?
Have you got another engineering station.

If there was a problem during download and the download procedure crashed somewhere, then unfortunately you usually do have to restart the PLC to resolve the problem. But the controller should continue to run the previous version of the program meantime, so don't panic, take your time and collect and analyze as much information as you can.

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by fibirt Rank: 1270 on 9/6/2018 7:35:11 AM | Like (0) | Report

Hello Rob, thanks for comments.
- CPU and all LEDs OK
- attempt to download from another engineering station with the same result
- getting online without download is without problem
- CPU is correctly running with last downloaded application
- before the problem with download new version couple of switchover between CPUs occured (we have redundancy configuration) - don´t know if this can be the reason

I tried to completely disconnect ethernet from both CPUs - still the same - OMG how is it possible that the controller is still occupied when it was more than 30 minutes completely without connection???!!! There is no procedure in CPU how to correctly finish session which is interrupted?

by Rob Lyon AKS expert

Rank: 2 on 9/6/2018 3:04:36 PM | Like (0) | Report

Disconnecting the controller from ethernet is irrelevant. The ES does not lock the AC800M like ONB does to Advant Controllers.

If you can successfully go online without download, and see all of the executing program, then the controller has the current version of the Application program.

Yes, redundant switch-over can quite possibly be related to your problem. You don't mention if you checked the controller logs yet. At the same time, Can you "Show Remote Systems" and check the program version loaded into the PLC and the last compiling station ?

As mentioned in another answer check the program just in case you do have an InhibitDownload function block active.

If possible you should try switching back to the primary CPU. But **beware** - this could go badly wrong if you don't know why the controller switched over in the first place, so check the controller logs first, and choose a time where a controller failure would have minimal impact.

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Rob Lyon

Rank: 2

Answered 18 days ago

Are you using InhibitDownload system function block?

Search for this function block and if you are using it, make sure it is False. If it is True, you won't be able to download to the controller.

Refer CBM online help for more information on this function block.

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AftabMemon Rank: 68

Answered 18 days ago

InhibitDownload syst.jpg

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Cannot login-Reservation of Controller failed

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