Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Mon, 2 Dec 2013 14:07:46 -0600

Hi Dirk,

On 11/27/2013 07:09 AM, Dirk Zimoch wrote:

I have added pp(TRUE) to some fields, so that the behavior is similar to
the calc record. The following fields are affected:

sel: SELM, SELN

seq: SELM, SELN, DO1, DO2, ... DOA

I don't want to make this kind of change to record behaviour in a

bug-fix release (3.14.12.4), although I will consider them for the 3.15

branch.

The seq record only has one field marked as pp(TRUE), the VAL field, and

the prompt text for that field is "Used to trigger", so I suspect the

implicit pp(FALSE) setting on the other fields was a deliberate design

decision by the author. I'm currently inclined to change the sel record

but not the seq, but would appreciate comments from anyone else about

this idea (which makes the two behave differently so I'm not really

convinced that's right either).

The disadvantage of making fields pp(TRUE) is that a client then has no

choice about processing the record, whereas for a pp(FALSE) field a

client can always follow up with a put to the PROC field (there's a

feature which display managers haven't implemented yet AFAIK). A

database designer can also insert an ao record in front of the relevant

fields of the seq record with a PP or NPP output link to change the

behaviour one way or the other, so there are workarounds to a field

having the wrong pp() setting.

- Andrew
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System