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Subject: RE: motor record v3.4 - home speed
From: Mark Rivers <[email protected]>
To: [email protected]
Cc: [email protected], [email protected]
Date: Tue, 23 Nov 1999 7:22:14 -0600
Hi,

> I think there's a problem in the motor record.
> ( v3.4 under EPICS 3.13.1 )
> 
> - the home fwd/rev (HOMR/HOMF) are supposed to 'hit home at 1000 steps per 
> sec.'
> 
> the conversion in motorRecord.c is erronous:
>    double hvel = 1000 * fabs(pmr->mres / pmr->eres);
>    [..]
>    WRITE_MSG(SET_VELOCITY, &hvel);
> 
> where:
>   mres = steps size in EGU
>   eres = steps / rev
> 
> hvel should simply be set to 1000.

I think you may misunderstand the meaning of the "eres" field, which you said
equals steps/rev.  eres is the encoder resolution, and has the same units as
"mres".  Thus, in most cases mres/eres is 1 (eres should be set to mres when
there is no encoder present).

However, I agree that there is a problem here.  Hardcoding 1000 steps/second
as the home speed is not the right thing to do - some controllers can home
faster, some must find home slower.  The home speed should be a settable field
in the motor record.

Mark Rivers


Replies:
Re: motor record v3.4 - home speed Ron Sluiter

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