Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Mon, 07 Feb 2005 11:13:51 +0100

It depends.
The length of the records' name fields has been discussed a lot in the
past - after some intermediate steps it has been raised for EPICS Base
3.14 to its current value of 61 bytes (which is 60 characters plus the
NULL). (Any record's include file in <BASE>/include will have the
definite answer in such cases - for any version of Base.)
Note that this is the limit of the EPICS IOC database record names. A PV
name (e.g. for Channel Access) may be longer (else you wouldn't be able
to address fields of a record with a 60 char name).
You are correct that other tools might have different limits. The chance
of running against a hardcoded limit of 28 or 40 characters actually
increases with the tool's age - EDM most probably being a safe choice.
Luckily enough EPICS stuff is distributed as source code so you at least
have a chance to fix things you don't like. ;-)
Good luck,
Ralph

Gavin Smith wrote:
Hello All,
What is the character limit on the length of PV names in EPICS? I have
seen things referring to 28 chars, 40 chars and 60 chars. Whilst I
have sucessfully made a record with a double alphabet name (i.e.
26x2=52 chars) I am wary that other programs (such as EDM) may have
different limits.
Thanks,
Gavin Smith.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System