Health points
- Last UpdatedApr 03, 2023
- 2 minute read
Health points enable an interface to store its status information in Data Archive, providing a history of interface operation. Interface health points pertain to the operation of the interface in general.
Health point details
|
Health Point |
Extended Descriptor (exdesc) Keyword |
Data Type |
When Updated |
When Reset |
|---|---|---|---|---|
|
Device Status |
[UI_DEVSTAT] |
String |
On change |
N/A |
|
Heartbeat |
[UI_HEARTBEAT] |
Integer |
Variable |
N/A |
|
Interface Point Count |
[UI_POINTCOUNT] |
Integer |
On change |
N/A |
|
IO Rate |
[UI_IORATE] |
Integer |
Heartbeat |
Heartbeat |
|
Message Count |
[UI_MSGCOUNT] |
Integer |
60 seconds |
N/A |
|
Output Bad Value Rate |
[UI_OUTPUTBVRATE] |
Integer |
Heartbeat |
Performance summary period |
|
Output Rate |
[UI_OUTPUTRATE] |
Integer |
Heartbeat |
Performance summary period |
|
Scan Class Bad Value Rate |
[UI_SCBVRATE] |
Integer |
At scan |
At Scan |
|
Scan Class Device Scan Time |
[UI_SCINDEVSCANTIME] |
Integer |
At scan |
N/A |
|
Scan Class Information |
[UI_SCINFO] |
String |
Perf interval |
N/A |
|
Scan Class IO Rate |
[UI_SCIORATE] |
Integer |
At scan |
At Scan |
|
Scan Class Point Count |
[UI_SCPOINTCOUNT] |
Integer |
On change |
N/A |
|
Scan Class Scan Count |
[UI_SCSCANCOUNT] |
Integer |
At scan |
Performance summary period |
|
Scan Class Scan Time |
[UI_SCINSCANTIME] |
Integer |
At scan |
N/A |
|
Scan Class Scans Skipped |
[UI_SCSKIPPED] |
Integer |
On change |
Performance summary period |
|
Trigger Bad Value Rate |
[UI_TRIGGERBVRATE] |
Integer |
Heartbeat |
Performance summary period |
|
Trigger Rate |
[UI_TRIGGERRATE] |
Integer |
Heartbeat |
Performance summary period |
-
Health point heartbeats
The heartbeat point is the primary PI point used to determine if the interface is running. If the value of the heartbeat point is updating, then the interface is running but not necessarily connected to and collecting data from a data source. The default update interval is 1 second if there are no scan classes defined for the interface.
If the interface has defined scan classes, the update interval will be set to the highest frequency (lowest value) scan rate with the following limitations. If the scan rate is less than 1 second, the update interval will be set to 1 second. If the scan rate for the highest frequency scan class is greater than 1 minute, the update interval will be set to 60 seconds. The value written to the heartbeat point increments from a value starting at 1, increments to a value of 15 and then restarts at 1.
The heartbeat point will stop updating if the interface is shut down or if the interface is in a deadlock situation.
Health point heartbeats are updated in the following way:
-
If there are no scan classes defined, the heartbeat updates once per second.
-
If one or more scan classes are defined for the interface, the heartbeat updates at the rate of the most frequent scan class.
-
Non-scan class health points are updated when the heartbeat is updated.
-
All scan class health points are updated when the class is scanned.
Some health points keep a running total of events until they are reset to 0. Several points are zeroed at the reporting period, which is based on the performance summary interval (by default, 8 hours).
During normal shutdown, the interface writes the system digital state of Intf Shut to all health points loaded by the interface.