Re: gdct313 - stepper-motor record problem.

[Bob Dalesio <dalesio@hotspur.atdiv.lanl.gov>]

The stepper motor record was intended to have readback from either
nothing entered - it's own position - this is totally open loop
.EPOS - the encoder - need to know the initial position so see IALG
some other position readback from an analog input.

We've used them before with the EPOS as the feedback.

	Bob


On Wed, 11 Feb 1998, Bill Brown wrote:

> 
> I'm experimenting with GDCT313 for a project that's starting to happen,
> and I've run into a problem.  Local people haven't done this particular
> thing before with this version, so it seems reasonable to toss it out
> for general comment.
> 
> We're using the OMS controller for stepper-motor drives.  Several of these
> drives will have encoder feedback.
> 
> I create the picture for the record, "export" the RDBL and EPOS fields, and
> link the output of EPOS to RDBL.  GDCT313 does this with no complaint.
> 
> The database which gets generated does not reflect this, however:
> 
> 	grecord(steppermotor,"Bl04:theFirstMotor") {
>         field(OUT,"#C0 S0 @")
>         field(RDBL,"Bl04:theFirstMotor.VAL PP MS")
>         field(MODE,"Position")
>         field(CMOD,"Position")
>     }
>     
> Note the RDBL is linked to the VAL field instead of the RDBL field. 
> Anybody have a clue as to why this is happening?  I _think_ I've got the
> base* files properly configured, and the cpu boots without complaint.  It
> even reads the .dbd and .db files without complaint.
> 
> I've got some wiring to do before I can "give it the smoke test," so it seems
> reasonable to ask for suggestions now, as it seems likely that the generated
> database isn't gonna do what I need it to do.
> 
> Any and all suggestions greatly appreciated.
> 
> -bill
>