Associated with: WITS Points.
The Alarms & Events attribute shows whether the point's Field Device, and/or the individual point, is inhibited. If there is an inhibit, the Field Device and/or point will not report alarms, report DNP3 events or log events.
Users can inhibit both the whole Field Device and individual points in the Field Device.
NOTE: The WITS standard refers to alarm and event inhibits as 'action inhibits'.
To inhibit an individual point in the Field Device, you use the Inhibit Alarms/Events (WITS Point) action.
To inhibit the whole Field Device, you use the Inhibit Alarms/Events (WITS Outstation) action.
If a user applies an inhibit, this will affect the behavior of the Field Device. ClearSCADA will still raise alarms and log events (if they are configured) if a point changes state. However, an inhibit may prevent a point from changing state.
The Device Profile defines the types of event that the Field Device supports and therefore that users can inhibit ((see Display a WITS Device Profile)).
The attribute shows the combination of events and alarms that is currently inhibited (if any). The possible states are as follows:
- Alarms, events and logged events inhibited—The Field Device will not report any point changes (that is, state, DNP3 object flag or other changes).
- Alarms and events inhibited—The Field Device will treat as logged events any point actions that are configured as alarms or events.
- Alarms inhibited—Point actions configured as alarms will behave like events. That is, the Field Device will not initiate a connection to ClearSCADA when a point changes.
- None inhibited—The Field Device performs all point actions as configured. Neither the point nor the Field Device is inhibited.
The format for the state information is as follows:
If both the individual point and the whole Field Device are inhibited:
<state> for point and <state> for outstation.
If the whole Field Device is inhibited:
<state> for outstation.
If only the point is inhibited:
<state> for point.
The <state> can be either Alarms, events and logged events inhibited, Alarms and events inhibited or Alarms inhibited.
The ability to inhibit a point is useful when you know that a point may generate unnecessary events. For example, if a measuring instrument has developed a fault.
Users may be able to inhibit alarms and events locally at the Field Device. You will be able to see any such inhibits on your ClearSCADA Status display when the Field Device reports its status, or the point's status.
When you apply an inhibit, you may also be able to apply a timeout. This is device dependent – it is defined in the device profile ((see Display a WITS Device Profile)). If you do apply a timeout, the Field Device will remove the inhibit after the timeout period and then report the new point status to ClearSCADA.
Further Information