Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Wed, 8 Aug 2001 15:12:20 -0600

> 
> We need to send strings of greater than 39 character length to the IOCs
> using CA.  I have developed new records and device support to do this
> based on existing the existing stringin and stringout software.  There
> seems to be a limit of 39 characters in CA.  Has anyone done this or
> solved the problem a different way?
> 

Short term:

You could change the field type to DBF_CHAR instead of DBF_STRING.
CA would write strings to this field using only type DBR_CHAR array
(not DBR_STRING), the system would be ignorant of the fact that 
your field is a string when converting between string and numeric 
types, and you might need to make extensive changes to the record's
source code to retain past behavior. After changing the field's data 
type general purpose clients might not display the PV as a string.
Admittedly a kludge.

Next release of EPICS base:

We could add a new (preferably variable length) string data type to 
CA and the EPICS database.

Jeff

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System