Specifications

Configuring Alarms for Points
PlantScape Server and Client Configuration Guide 157
Alarms on Transition for Status Points
You can also configure alarms to be generated if the PV of a point changes from
one alarm state to another. For example, if you define both CLOSED and FAILED
as alarm states for a valve, the server generates an alarm when the valve fails, and
generates an additional alarm when the valve closes as a result of the failure.
Control Fail Alarms for Status Points
When a status point control is issued, the server tests for control failure as
follows:
• After an OP, MD, or a parameter control is issued, a demand scan on the
source address is performed by the server. If the scanned value does not
match the controlled value, a control fail alarm is generated.
• If a control timeout value has been defined on the Control property sheet, a
PV Fail Alarm will be generated when the PV fails to match the OP. (See the
description of “Control Timeout for Status Points” on page 150.)
External Change Alarms for Status Points
An external change is a change in the value of a parameter that is not caused
directly by an operator control issued through the server. An alarm is issued
when the value referenced by the parameter is changed in the field device.
For status points, you can enable alarms for external changes in PV, OP and MD.
Note The external change alarm setting applies only to the parameter being directly
controlled. For example:
• Point1 and Point2 are built with their OPs viewing the same field location
and with external change alarms enabled on their OPs. An operator control
to the OP of Point1 is an external change to the OP of Point2, so Point2
issues an external change alarm.
• Point3 is built with its PV and OP viewing the same field location and with
external change alarms enabled for the PV. An operator control to the OP is
an external change to the PV, so the point issues an external change alarm.
Specifying Addresses for Alarm Acknowledgments
For status points, you can use Quick Builder to specify an address (for example,
in a controller) to which the alarm acknowledgment can be written.
The address is shown on the Alarms tab of the Status Point Detail display, in the
Controller Destination Address field.
plscpcg.book Page 157 Monday, May 28, 2001 10:11 AM