Notifier UniNet 2000, Installation, Operation, And Administration Manual

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The Workstation Installation/Operation Manual Version 2 Document 51540 Rev. B1 4/8/02
4.10.4 Functional Properties of the 2C8M / 16C48M
There are several properties involved with the operation of inputs and outputs on discrete point NIONs. Each of
these properties must be considered carefully when configuring points and I/O schedules.
Input Properties
The two main properties of any discrete NION input are its mode and state .
Mode - The mode of an input is a logical condition assigned to the point which controls the way data from the
input is handled, recorded or annunciated. Each input on a NION may be placed in one of four operational
modes. These are:
ARM
DISARM
OVERRIDE
DISABLE
State - The state of the input is the actual physical status of the point being monitored. The four states are:
Input Active
Input Normal
Open Circuit
Short Circuit
The NION reports different point states based on the current operational mode of the input.
Rules for Mode Change Commands
The mode of any input may be changed by one of three methods:
Scheduled - time codes defined in the plug-in. When a time code becomes active (Start Time) the input is
disarmed. When the time code expires (Stop Time) the input is armed. During the intermediate time
between start and stop, the scheduler will not automatically alter the mode of an input.
Manual - user action. Such action can only be initiated from the workstation.
Automatic - UniLogic equation execution. After evaluating an equation, UniLogic may execute an action
which sends a command to the NION.
Scheduled, manual and automatic are all equivalent in priority. As each mode change command is received it is
given priority over any previously received command.
NOTE: There are exceptions to the rule of equal priority between mode change commands.
These exceptions are noted as follows and in the detailed description of each mode below.
One exception to this rule concerns trouble conditions. When a point enters a trouble state (Open Circuit or Short
Circuit) and the point is not currently in Disabled mode, a trouble condition is immediately reported. Until the
trouble condition clears, the point may only be moved to Disabled mode. All other mode change commands are
ignored. If the point is moved to Disabled mode, a TROUBLE OFF event is generated prior to the DISABLE event.
When the trouble condition clears and if the point is not Disabled, then control of the point defaults to the Sched-
uler which immediately Arms or Disarms the point according to the time code.
ARM - When a point is in Armed mode it monitors the state of the input and reports trouble, input active and input
normal conditions. The following rules apply:
1. Any time an input point transitions into the Armed mode, an ARMED event will immediately be reported. If
the point is active, an INPUT ACTIVE event will be sent immediately after the ARM event.
2. A point in trouble cannot be Armed. When an Arm command is received by a point that is in trouble the
cammand will be ignored.