Innis01 Network Interface Slave Module; Exception Reports; Messages; Broadcast - Bailey INFI 90 Instruction

DESCRIPTION AND OPERATION

Messages

INNIS01 NETWORK INTERFACE SLAVE MODULE

2 - 2
sends this message to other INFI-NET nodes. This process
reduces the number of transmissions required, and adjusts
the message size for maximum INFI-NET loop efficiency.
Exception reports can have data values in the following for-
mats: Boolean, analog, digital and status report. Exception
reports are time stamped to reflect their processing sequence.
The maximum and minimum report time parameters insure
that an exception report is generated for static or rapidly
changing data. The minimum report time parameter controls
the quantity of exception reports a single rapidly changing
point generates. The maximum report time parameter gener-
ates a periodic exception report of data items that do not
change or change very slowly.
NOTE: If a point goes into or out of alarm, the time parameters are
ignored and an exception report is generated immediately.
The NIS module processes four different message types. They
are broadcast, time synchronization, multicast, and NIS poll.

BROADCAST

The NIS module generates a broadcast message when sending
information to all system nodes. Typically, these messages
announce changes in node status. Broadcast messages
include NODE ONLINE, NODE OFFLINE, NODE RESTART and
NODE BUSY.

TIME SYNCHRONIZATION

The time synchronization message is a high priority broadcast
type of message. The NIS module services this message type
immediately. Time synchronization provides a common system
time base to be used for sequencing exception reports, access-
ing trend data, and display on a system console.

MULTICAST

A message that contains data for multiple destinations is a
multicast message. This message can have from one to 64
destinations.

NIS POLL

The NIS poll message is a single destination message. The NIS
module uses this message type to poll the operational status of
another node.

MESSAGE FORMAT

Messages exist as frames of information. Each frame consists
of a message control field that follows an information field. The
®
I-E96-610A