Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Fri, 22 Oct 2010 09:42:08 -0400

 On 21.10.2010 21:25, Ben Franksen wrote:

Yes. I use this record type heavily for all sorts of conversion tasks.
It is one of the most-reused pieces of code I have ever written.

The cvt record is a lot more flexible than ao. As Ralph indicated, it is
not restricted to functions of one input variable, but can also read
and interpolate two-dimensional tables, i.e. calculate the output from
from two independent inputs. Furthermore, it can load / reload tables
at runtime. The actual loading of the table is done asynchronously and
proceeds in parallel to the conversion, i.e. conversion continues to
run while the table is loaded in the background. Only after the table
has successfully been loaded is it swapped in for the old one. This
means you can correct or adjust tables in a running system w/o having
to stop the feedforward.

Question to core:

As we have seen, the conversion problem occurs at many sites, and

everyone wrote their own way out by creating a new record type.

I think it would be safe to say that this type of conversion is an

often-needed functionality that the EPICS core record set is missing.

Should we include one of the solutions - this record or the stuff from

asyn, whatever is more generic and appropriate - as part of base?

~Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System