The ACNET Data Consolidator
B. Lublinsky
Fermilab
Many of Fermilab's control systems are located around the Ring and are doing
measurements for the specific houses. Examples of such systems are: Cryogenic
controls, BPMs, QPMs, Vacuum, etc. Very often users are interested in the
similar data collected around the ring that allow them to understand the global
characteristics of the process. There are 2 ways of accessing these kinds of
data: individual reads from different houses or "ring-wide" reads. Obviously,
from the user point of view and from the point of view of resource utilization
"ring-wide" reads are much more convenient. Up until recently all control
modules were connected to CAMAC links and served by the same Front End computer
that was implementing "ring-wide" consolidation. During the last several years
the situation has changed significantly, the new generation control systems are
connected directly to the network; thus it was necessary to introduce a network
server to consolidate messages to remote control systems.
The network consolidator is VxWorks based 68040 microprocessor, residing in a
VME chassis, that can communicate on both Ethernet and Token Ring (the two
networks used in the Fermilab control system). Consolidator software is table
driven consolidation - user specifies the consolidation table that he wants to
use and his request is resent to all nodes that are in the table. The reply
from all nodes is assembled together and sent back to the original requester.
Internally, consolidator is based on the dynamic pool, that is keeping track of
all currently active requests and making sure that requests to the remote nodes
are not duplicated. It also combines internal requests to the remote nodes,
thus minimizing the network traffic. Currently consolidator is used to perform
"ring-wide" requests for the cryogenic control system. There are plans to use
it for BPM "ring-wide" support.