Re: DRVL, DRVH, HOPR, LOPR

[Dirk Zimoch <dirk.zimoch@psi.ch>]

Luedeke Andreas wrote:
> > Questions: 
> > 1. how does one (especially the client) know that the limits are really set? And not default values.
> > 2. if it performs a check that HOPR!=LOPR then what if one defines an upper limit (but does not need a low one) and vice-versa.
> to 1.) 
> As pointed out previously: The client does not know it. 
> Of course DRVH/L are already handled by the record: if DRVH=DRVL=0 then only a "0" can be written to the hardware
This is wrong. DRVH and DRVL are only used if DRVH > DRVL.

That means of course in particular if DRVH=DRVL=0 then ANY value can be 
written.
Thus a client can check for DRVH > DRVL or DRVH!=0 and DRVL!=0.

Dirk




> But HOPR and LOPR are not used by all clients. 
> If you want to use them in any client, take care that they are set for ALL records that are meant to be used by any client.
> to 2.)
> The only way to allow HOPR and LOPR to be set individually would be to change the default: HOPR=+Inf and LOPR=-Inf.
> But this is not really useful: e.g. if you want to present a control slider you need two limits to just show it.
> And if just one client has a problem with one unset limit, then you'll need to set all limits.
>
>
> Just drop the idea of not setting HOPR or LOPR for any relevant PV.
> Every PV has to have a valid range.
>
>
> Andreas