答复: AutoSaveRestore of the motor position

[张招红 <zhangzhaohong@sinap.ac.cn>]

Thanks for your suggestion.
Perhaps we shoud pay our attention to the MAXv-8000 card.If the card don't
give up working,the autoSaveRestore problem will not happen too.

-----邮件原件-----
发件人: Ron Sluiter [mailto:sluiter@aps.anl.gov] 
发送时间: Monday, May 10, 2010 10:52 PM
收件人: 张招红
抄送: tech-talk@aps.anl.gov
主题: Re: AutoSaveRestore of the motor position

The scenario you describe is the same as if you commanded the motor to
make a long move and lost IOC power during the move. At IOC boot-up,
autosave would restore the motor's position to the last commanded value,
not the actual position.

Ideally, you would have autosave record the actual position (DRBV) and
use it to restore both the actual and the commanded positions (DVAL) at
boot-up. Autosave is not currently capable of doing that and I question if
it needs to. Recording actual, as opposed to commanded positions,
would incur data acquisition like levels of overhead for something that
rarely happens.

Ron

张招红 wrote:
>
> Hi，everybody,
>
> In SSRF beamline control we use the autosave module to save the 'DVAL'
> field and restore the value of a motor position when rebooting.
>
> Recently we encountered a problem.
>
> Sometimes one of the controllers(MAXv-8000) in a VME crate crashes
> while the IOC(mvme5500) still runs. Because the motor channel is still
> connected, the system looks OK. In this case if changing the ‘DVAL’
> field to drive the motor, the controller doesn’t response and the
> ‘DRBV’ of the motor keeps unchanged. So the saved value 'DVAL' isn't
> no long the motor real position.
>
> When hard rebooting the VME crate, the 'DRBV' set by the recovered
> 'DVAL' doesn't match the motor real position.
>
> Are there some problems in our saving and restoring method? How to
> deal with this kind of problem?
>
> Any suggestion will be greatly appreciated!
>
> ===================================================
> Zhang Zhaohong（张招红）
> No.239 Zhangheng Road
> PuDong District
> Shanghai Institute of Applied Physics CAS
> Shanghai, China
> Tel: +86-21-33933238
>