Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Sun, 15 Mar 2015 21:11:03 +0100

Hi Andrew,

Yup - if you want to allow restarting through Channel Access, that's the

way to do it.

With the appropriate command line option, procServ will restart any

child process that exits. On regular IOCs, devIocStats is a portable way

to have CA execute a reset/exit. On your python IOCs, you will have to

add one PV that calls exit() when it is written to.

The minimum common PV that you can use to show the IOC is alive would be

the PV you use to issue the reset. If you add the functionality to the

python IOCs, that PV can be made common across all your IOCs.

Another option would be to use procServ's kill/restart command to

restart the IOC. That does not need devIocStats or any addition to the

python IOCs, but needs a bit more thought on the client side: The button

will have to connect to the procServ session (using telnet or netcat)

and send the restart control character. You would have to find a

reliable way to to that (start with echoing the control character to

netcat).

Advantage: works with*any* child of procServ, not just IOCs.

Disadvantages: you would still need a common PV to show the IOC is up,

and the mechanism needs to be configured (IP and port for each IOC),

while in the other case the reset PV name can be nice and generic, and

you don't need to know the procServ ports.

Cheers,
~Ralph

On 15/03/2015 20:46, Andrew Gomella wrote:

Hi everyone,

For some context, we are constantly switching hardware in and out so

we are constantly stopping/starting soft IOC's. Some of our users only

use EPICS rarely, and I would like to be able to tell them (over the

phone for instance) to "restart ______ IOC" without walking through a

multi-step procedure.

Right now we can make it very easy for end users to start IOC's by

using the "execute shell script" button on caqtdm (or MEDM). However,

what I would like is a way for the end user to see which IOC's are

running, and have a few simple buttons like start/stop to control them.

I was thinking of installing both procserv and devIocStats and using

these together. (Though deviocstats won't work with several of our

python channel access servers)

I was thinking a simple, not very elegant way, would be to choose some

arbitrary PV from each given IOC and monitor that to determine whether

to indicate to the end user whether the IOC is online.

Look forward to hearing any suggestions!

Thanks,
Andrew

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System