Re: AsynPortDriver setting DRVH of ao?

[Florian Feldbauer <florian@ep1.ruhr-uni-bochum.de>]

Hey Mark,

I knew the possibility of using such a record chain as you are 
suggesting, but
this is a bit more difficult in my case (I will need 17 records).
Our power supply has one maximum voltage value, but 16 channels which 
all needs the DRVH....
Therefore I had hoped, that there is some mechanism within asynDriver
(like in streamDevice using the @init and redirection mechanisms)
I will use the records chains then.
Thanks for your quick answer!

Cheers,
Florian

On 10/15/2014 05:00 PM, Mark Rivers wrote:
> Hi Florian,
>
> This can easily be done by using 2 additional records.
>
> Define a new asynFloat64 parameter in your driver which is the maximum voltage that you read back from the remote control interface.  This could have a drvInfo field of MAX_VOLTAGE, for example.  Make sure your driver sets the flag that registers it as an interrupt source on the asynFloat64 interface.
>
> Your database would then look like this:
>
> record(ai, "$(P)$(R)MaxVoltage")
> {
>      field(DTYP, "asynFloat64")
>      field(INP, "@asyn($(PORT),0,1)MAX_VOLTAGE
>      field(SCAN, "I/O Intr")
>      field(FLNK, "$(P)$(R)SetMaxVoltage")
> }
>
> record(ao, "$(P)$(R)SetMaxVoltage")
>      field(DOL, "$(P)$(R)MaxVoltage NPP")
>      field(OMSL, "closed_loop")
>      field(OUT, "$(P)$(R)Voltage.DRVH NPP")
> }
>
> So the MaxVoltage will process whenever your driver sets a new value for the MAX_VOLTAGE parameter.  That will cause the SetMaxVoltage record to process, which copies the value of MaxVoltage to the DRVH field of your existing Voltage ao record.
>
> Mark
>
>
>
> -----Original Message-----
> From: Florian Feldbauer [mailto:florian@ep1.ruhr-uni-bochum.de]
> Sent: Wednesday, October 15, 2014 8:11 AM
> To: Mark Rivers; EPICS Tech Talk
> Subject: AsynPortDriver setting DRVH of ao?
>
> Hey Mark,
>
> I'm using the asynPortDriver for some of my device support routines.
> Now we have a power supply were the maximum voltage can be limited via a
> poti.
> The actual value can be read out via the remote control interface.
> We would like to use this value for the DRVH field of the ao records
> used to set the output voltage.
>
> Is it possible (e.g. during initialization) to set the DRVH fields via
> the asynPortDriver?
>
> Best regards,
> Florian

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| Dr. Florian Feldbauer                |
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| Helmholtz-Institut Mainz /           |
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