Point

When configured curVal automatically tracks changes to writeVal and curStatus is set to "ok". This tag is ignored if the current value is bound to connector.

Enables COV history collection of the curVal. The tag value must be Marker to collect on any change. Or if the point is Numeric, then the value may be a Number which indicates the tolerance a point must change before logged.

COV collection is rate throttled using a limit determined as follows:

• use hisCollectCovRateLimit if configured
• if a numeric with hisCollectInterval, then never collect faster than 1/10 of the interval or 1min (whichever is lower)
• if a numeric without hisCollectInterval then use 1min as rate limit
• fallback to 1sec rate limit for non-numerics

Also see hx.point.

Rate limits the frequency for hisCollectCov. When configured COV logging will never log any faster than this frequency. For example if set to 10sec, then the historian will log no faster than every 10sec even if the underlying data is changing every second.

Enables interval history collection of the curVal. The value must be a duration Number with a "sec", "min," or "hr" unit:

• if secondly, then must be divisible evenly into a 60sec minute
• if minutely, then must be evenly divisible into a 60min hour
• if hourly, then must be evenly divisible into a 24hr day

Also see hx.point.

Historize the NA value whenever the curVal is null or curStatus is not equal to "ok". If this marker is omitted, then no value is logged in this sitaution. This behavior may be changed on for the entire project by adding this tag as a point setting.

This tag configures how long to buffer collected history items in memory before flushing them to the historian. If this tag is missing, then collected items are immediately flushed to the historian and to disk. But when this tag is configured with a duration number, items are be buffered in memory and then written to the historian in batch. Batch writes enable more efficient compression of the history data and allows you to tune how often data is fsync'ed to disk.