Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Mon, 19 Jul 2004 18:26:59 +0200

  > 1. The archiver gets a lot more data. Is ADEL ignored through the 
  > gateway? Does the gateway make DBE_VALUE monitors from DBE_LOG monitors?
  > I tried '-mask avl' but that didn't help.
  > If the gateway does not preserve the type of monitor (v or l), why not?

Any CA client can set up a monitor specifying an event mask telling the
server which kind of events it is interested in.

Alas, when the data update messages come in, CA does not tell the client
for what reason a particular update was sent.

The Gateway can set up its IOC side connection for multiple event types,
but has to distribute the event to all the Gateway's clients because the
upcoming data has no tag which event type triggered the update, so the
Gateway simply has no way of knowing which clients to send it to.

There's a workaround that was implemented a while ago: the Gateway takes
a command line argument specifying what value event mask it should use
on its IOC side.

With that trick e.g. an archiver can be pointed to a special Gateway
that is started with '-mask l' to see only DBE_LOG updates.

The appropriate extension/change of the CA protocol (tagging the data
update with the event types that triggered that update) is on the list
for the next major CA update.

Hope this helps,
Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System