Re: limit switch fields in the motor record

["Davis, Mark via Tech-talk" <tech-talk@aps.anl.gov>]

I agree.  Especially since it just occurred to me that that any 
additional external logic to get around this that uses the bits in the 
MSTA field instead also has to take in to account the value of the DIR 
field as well (and possibly others that I haven't yet discovered...).

At the very least, there should be a way to disable this behavior, even 
if it is on by default to insure backwards compatibility.

In addition to not having them both come on when a cable is unplugged, I 
can imagine multiple scenarios where this behavior could mask various 
problems.

At the very least, there should be something to indicate a problem if 
the limit switch that does NOT correspond to the TDIR value is triggered 
(if it doesn't already, it could at least set the PROBLEM bit in the 
MSTA field)

Mark


Mark Davis NSCL/FRIB Control Systems Software Engineer davism50@msu.edu
On 4/9/2019 1:59 PM, Mark Rivers wrote:
> I agree that this is a bad behavior and I have complained about it for years.  I think it's origin was in an old motor controller that could only tell you that it was at a limit, but not which one.  So it needed to use the direction to figure that out.
>
> I would like to be able to unplug my motor cable with the limit connections and immediately see both limit lights on the OPI screen.
>
> Mark
>
>
> -----Original Message-----
> From: tech-talk-bounces@aps.anl.gov <tech-talk-bounces@aps.anl.gov> On Behalf Of Davis, Mark via Tech-talk
> Sent: Tuesday, April 9, 2019 12:57 PM
> To: tech-talk@aps.anl.gov
> Subject: limit switch fields in the motor record
>
> Is there a reason that the xLS/RxLS limit switch fields in the motor record only work when the TDIR field's value indicates that the motor is or was last moving in the direction that would normally trigger the corresponding limit switch?
>
> This means that that only way to know if a limit switch has REALLY been triggered is to monitor the bits in the MSTA field.
>
> I am using version 6-9 of the motor record if that makes any difference.
>
> Mark Davis, NSCL/FRIB
> Control Systems Software Engineer
> davism50@msu.edu