Experimental Physics and
Industrial Control System

Sue Witherspoon <[email protected]> · Tue, 04 Jan 2000 14:20:18 -0500

William Lupton wrote:
> 
> Hi. I have an alarm handler question...
> 
> We sometimes use the FORCEPV temporarily to disable alarms. For example,
> we have a vacuum error which is disabled when the telescope is slewing
> (so its mask is set to --D-- during the slew and then back to its
> default of ----- on completion of the slew).
> 
> Last night, the vacuum alarms were being generated spuriously, so the
> operator tried to disable them. However, each time a slew completed, the
> mask was set back to the default of -----, not the operator override of
> --D--.
> 
> Also, although this is specific to our operational environment, the field
> which indicates slew/track is actually posted every 20 seconds
> regardless of whether its state changed. This means that the mask is set
> back to its default every 20 seconds regardless of whether the
> slew/track state actually changed (because the FORCEPV logic checks
> whether the current value matches the force or reset values; it doesn't
> check for a transition).
> 
> So, I am asking whether it would be reasonable to do the following:
> 
> a) allow the FORCEPV reset mask to honor any operator overrides,
> 
> b) allow the FORCEPV logic to check for transitions to the force or
>    reset values
> 
> Of course, I apologise unreservedly if we are inadvertently using an old
> version and these issues have already been resolved. Happy new year to
> all.
> 

I'm interested in this issue, for the same sort of scenario occurred
here at Jefferson Lab. It was resolved, probably not elegantly, by
using the cancel mask for the FORCEPV  C----- and leaving the
operators the disable masks to work as expected. 
______________________________________________________________
Sue D. Witherspoon                      TJNAF - CEBA 
[email protected]                        (757) 269-7579 
If my people would Humble, Pray, Seek and Turn....2 Chron. 7:14

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System