Experimental Physics and
Industrial Control System

Dirk Zimoch <[email protected]> · Wed, 01 Oct 2008 13:57:19 +0200

Andrew Johnson wrote:

Hi Zen,
On Tuesday 30 September 2008 17:09:25 Szalata, Zenon M. wrote:

Is it possible to control the order in which epics records are initialized

when the IOC starts up? I am working on an IOC for a device and I would

like to reset this device. I have an output record which writes a number

to the device at init time (PINI=YES), which resets it. In order that my

scheme works, this record needs to be initialized before any other record.
I am using streamdevice with asyn. I am tracing all IO and I see that the

initialization order is arbitrary. Any help would be appreciated,

As you have discovered, the IOC's record initialization order is not
specified. In practice I believe it's currently ordered first by record type
in the order of entry in the DBD file, and within each record type in
alphabetical order by record name, but I wouldn't suggest that you rely on
that order in case it changes in future releases.
I don't know whether streamdevice allows you to specify an initialization
message that can be sent to the device at startup; if it does use that to
perform the reset rather than relying on your reset record. If not, try and
do the reset from an iocsh/vxWorks command that you can put in the st.cmd
file before iocInit. If you can't work out how to do that, maybe you could
link all your device I/O records SDIS links to an "initialized" record which
only lets them process after the reset has happened (this makes setting PINI
on any of them a bit of a lottery though).
HTH,
- Andrew

StreamDevice can send messages earlier than PINI in the @init handler. This
actually happens during init_record and is meant to initialize output records
from the hardware. But still then the order of @init handlers of different
records is undefined.
--
Dr. Dirk Zimoch
Paul Scherrer Institut, WBGB/006
5232 Villigen PSI, Switzerland
Phone +41 56 310 5182

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System