Rate, in seconds, at which subscription callbacks occur
UpdateRate
specifies the rate, in seconds, at which
subscription callbacks occur. Therefore, UpdateRate
determines
how often the cached data can be updated and how often data change events can occur.
Consequently, UpdateRate
also controls the rate at which data is
logged. You start logging data change events with the start
function.
Data change events can occur only for active items in an active group. Additionally, subscription must be enabled for the group.
Note that servers can select an update rate that differs from the requested value.
If this occurs, UpdateRate
is automatically updated with the
returned value. By specifying an update rate of 0
, updates will
occur as soon as new information becomes available for the daitem
object. New information is considered to be a change in the Quality
property or a change in the data Value
that exceeds the DeadbandPercent
property value.
Access |
Read-only while logging |
Applies to |
|
Data type |
double |
Values |
Any value greater than or equal to |