Internal communication
The internal communication in ProviewR sends information about volumes, objects,
alarms, events, history data etc. between processes and nodes. There are three
different protocols for alarm handling, net handling and history data, the all are
based on Qcom.
Qcom
Qcom is a message bus that sends queued messages between processes. Communicating
nodes all have to share the QCom bus, and a node can only attach one bus. The bus
is configured in the BusConfig object by stating the bus identity, a value between
1 and 999.
You also have to configure which nodes are to communicate with each other. With the
default configuration, all nodes in the same project will communicate, and additional
nodes in other project is configured with FriendNodeConfig objects. This can for example
be process stations that are mounted by operator stations.
If you have a project with several nodes, and don't want them all to communicate with
each other, you can set QComAutoConnectDisable in the BusConfig object, and specify
the communcation links with FriendNodeConfig objects.
All Qcom messages are sent with acknowlegement. If the acknowlege doesn't arrive, the
message is resent with double timeout. After a number of resends without reply the link
is regarded to be down. Dependent on the type of net and transmission speed, the timeouts
might have to be adjusted. This can be done with the ResendTime attributes in the
NodeConfig and FriendNodeConfig objects.
See the document QCOM for more information about Qcom.
Nethandler
The nethandler sends information about volumes and objects between nodes, for example
the volumes in a node, the parent, children or siblings of an object, or the content
of an object or attribute. Also subscriptions are set up via the nethandler, that is
data cyclically sent from one node to another, usually from process stations to operator
stations. The processes for the net handling are rt_neth, rt_neth_acp and rt_tmon.
Eventhandler
The event handler scans all the supervision object in a node and sends alarms and
events to outunits, for example to the alarm and event lists in the operator enviroment.
They send acknowlegdements back to the event handler. Exactly which alarms and event that
is sent to an outunit is configured in the select list. The select list for the operator
environment is found in the the OpPlace object. Only events and alarms below the stated
hierachies are sent. The process of the event handling, rt_emon, is configured with a
MessageHandler object.
Historical data storage
The historical data storage means that data is sent from process stations and stored in
a database in a storage server. The server process rt_sevhistmon in the process station
scans all attributes marked for storage, fetches the corresponding values and sends them
to the sev_server process that stores them into the database. When curves of historical data
are to be displayed, a request is sent from the operator environment and a suitable
selection of points are fetched from the database and sent to the operator environment.
See chapter Data Storage
Web and app communication
The web interface and Andriod application fetches information from the ProviewR realtime
database through the server processes rt_webmon, rt_webmonmh and rt_webmonelog. This
communication is configured by the WebHandler object.
Status server
The Runtime monitor and Supervision center fetches information from the Status server.
This communication is based on http and soap, and is configured with the StatusServerConfig
object.